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parser-bottom-up.c

     
 //! @file parser-bottom-up.c
 //! @author J. Marcel van der Veer
 //!
 //! @section Copyright
 //!
 //! This file is part of Algol68G - an Algol 68 compiler-interpreter.
 //! Copyright 2001-2023 J. Marcel van der Veer [algol68g@xs4all.nl].
 //!
 //! @section License
 //!
 //! This program is free software; you can redistribute it and/or modify it 
 //! under the terms of the GNU General Public License as published by the 
 //! Free Software Foundation; either version 3 of the License, or 
 //! (at your option) any later version.
 //!
 //! This program is distributed in the hope that it will be useful, but 
 //! WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
 //! or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 
 //! more details. You should have received a copy of the GNU General Public 
 //! License along with this program. If not, see [http://www.gnu.org/licenses/].
 
 //! @section Synopsis 
 //!
 //! Hand-coded bottom-up parser for Algol 68.
 
 // This code constitutes an effective "Algol 68 VW parser"; a pragmatic
 // approach was chosen since in the early days of Algol 68, many "ab initio" 
 // implementations failed.
 // 
 // This is a Mailloux-type parser, in the sense that it scans a "phrase" for
 // definitions needed for parsing, and therefore allows for tags to be used
 // before they are defined, which gives some freedom in top-down programming.
 // 
 //    B. J. Mailloux. On the implementation of Algol 68.
 //    Thesis, Universiteit van Amsterdam (Mathematisch Centrum) [1968].
 // 
 // Technically, Mailloux's approach renders the two-level grammar LALR.
 // 
 // This is the bottom-up parser that resolves the structure of the program.
 
 #include "a68g.h"
 #include "a68g-parser.h"
 #include "a68g-prelude.h"
 
 // Bottom-up parser, reduces all constructs.
 
 //! @brief Whether a series is serial or collateral.
 
 int serial_or_collateral (NODE_T * p)
 {
   NODE_T *q;
   int semis = 0, commas = 0, exits = 0;
   for (q = p; q != NO_NODE; FORWARD (q)) {
     if (IS (q, COMMA_SYMBOL)) {
       commas++;
     } else if (IS (q, SEMI_SYMBOL)) {
       semis++;
     } else if (IS (q, EXIT_SYMBOL)) {
       exits++;
     }
   }
   if (semis == 0 && exits == 0 && commas > 0) {
     return COLLATERAL_CLAUSE;
   } else if ((semis > 0 || exits > 0) && commas == 0) {
     return SERIAL_CLAUSE;
   } else if (semis == 0 && exits == 0 && commas == 0) {
     return SERIAL_CLAUSE;
   } else {
 // Heuristic guess to give intelligible error message.
     return (semis + exits) >= (commas ? SERIAL_CLAUSE : COLLATERAL_CLAUSE);
   }
 }
 
 //! @brief Insert a node with attribute "a" after "p".
 
 void pad_node (NODE_T * p, int a)
 {
 // This is used to fill information that Algol 68 does not require to be present.
 // Filling in gives one format for such construct; this helps later passes.
   NODE_T *z = new_node ();
   *z = *p;
   if (GINFO (p) != NO_GINFO) {
     GINFO (z) = new_genie_info ();
   }
   PREVIOUS (z) = p;
   SUB (z) = NO_NODE;
   ATTRIBUTE (z) = a;
   MOID (z) = NO_MOID;
   if (NEXT (z) != NO_NODE) {
     PREVIOUS (NEXT (z)) = z;
   }
   NEXT (p) = z;
 }
 
 //! @brief Diagnose extensions.
 
 void a68_extension (NODE_T * p)
 {
   if (OPTION_PORTCHECK (&A68_JOB)) {
     diagnostic (A68_WARNING | A68_FORCE_DIAGNOSTICS, p, WARNING_EXTENSION);
   } else {
     diagnostic (A68_WARNING, p, WARNING_EXTENSION);
   }
 }
 
 //! @brief Diagnose for clauses not yielding a value.
 
 void empty_clause (NODE_T * p)
 {
   diagnostic (A68_SYNTAX_ERROR, p, ERROR_CLAUSE_WITHOUT_VALUE);
 }
 
 #if !defined (BUILD_PARALLEL_CLAUSE)
 
 //! @brief Diagnose for parallel clause.
 
 void par_clause (NODE_T * p)
 {
   diagnostic (A68_SYNTAX_ERROR, p, ERROR_NO_PARALLEL_CLAUSE);
 }
 
 #endif
 
 //! @brief Diagnose for missing symbol.
 
 void strange_tokens (NODE_T * p)
 {
   NODE_T *q = ((p != NO_NODE && NEXT (p) != NO_NODE) ? NEXT (p) : p);
   diagnostic (A68_SYNTAX_ERROR, q, ERROR_SYNTAX_STRANGE_TOKENS);
 }
 
 //! @brief Diagnose for strange separator.
 
 void strange_separator (NODE_T * p)
 {
   NODE_T *q = ((p != NO_NODE && NEXT (p) != NO_NODE) ? NEXT (p) : p);
   diagnostic (A68_SYNTAX_ERROR, q, ERROR_SYNTAX_STRANGE_SEPARATOR);
 }
 
 //! @brief If match then reduce a sentence, the core BU parser routine.
 
 void reduce (NODE_T * p, void (*a) (NODE_T *), BOOL_T * z, ...)
 {
   va_list list;
   int result, expect;
   NODE_T *head = p, *tail = NO_NODE;
   va_start (list, z);
   result = va_arg (list, int);
   while ((expect = va_arg (list, int)) != STOP)
   {
     BOOL_T keep_matching;
     if (p == NO_NODE) {
       keep_matching = A68_FALSE;
     } else if (expect == WILDCARD) {
 // WILDCARD matches any Algol68G non terminal, but no keyword.
       keep_matching = (BOOL_T) (non_terminal_string (A68 (edit_line), ATTRIBUTE (p)) != NO_TEXT);
     } else {
       if (expect == SKIP) {
 // Stray "~" matches expected SKIP.
         if (IS (p, OPERATOR) && IS_LITERALLY (p, "~")) {
           ATTRIBUTE (p) = SKIP;
         }
       }
       if (expect >= 0) {
         keep_matching = (BOOL_T) (expect == ATTRIBUTE (p));
       } else {
         keep_matching = (BOOL_T) (expect != ATTRIBUTE (p));
       }
     }
     if (keep_matching) {
       tail = p;
       FORWARD (p);
     } else {
       va_end (list);
       return;
     }
   }
 // Print parser reductions.
   if (head != NO_NODE && OPTION_REDUCTIONS (&A68_JOB) && LINE_NUMBER (head) > 0) {
     NODE_T *q;
     int count = 0;
     A68_PARSER (reductions)++;
     WIS (head);
     ASSERT (snprintf (A68 (output_line), SNPRINTF_SIZE, "\nReduction %d: %s<-", A68_PARSER (reductions), non_terminal_string (A68 (edit_line), result)) >= 0);
     WRITE (STDOUT_FILENO, A68 (output_line));
     for (q = head; q != NO_NODE && tail != NO_NODE && q != NEXT (tail); FORWARD (q), count++) {
       int gatt = ATTRIBUTE (q);
       char *str = non_terminal_string (A68 (input_line), gatt);
       if (count > 0) {
         WRITE (STDOUT_FILENO, ", ");
       }
       if (str != NO_TEXT) {
         WRITE (STDOUT_FILENO, str);
         if (gatt == IDENTIFIER || gatt == OPERATOR || gatt == DENOTATION || gatt == INDICANT) {
           ASSERT (snprintf (A68 (output_line), SNPRINTF_SIZE, " \"%s\"", NSYMBOL (q)) >= 0);
           WRITE (STDOUT_FILENO, A68 (output_line));
         }
       } else {
         WRITE (STDOUT_FILENO, NSYMBOL (q));
       }
     }
   }
 // Make reduction.
   if (a != NO_NOTE) {
     a (head);
   }
   make_sub (head, tail, result);
   va_end (list);
   if (z != NO_TICK) {
     *z = A68_TRUE;
   }
 }
 
 //! @brief Graciously ignore extra semicolons.
 
 void ignore_superfluous_semicolons (NODE_T * p)
 {
 // This routine relaxes the parser a bit with respect to superfluous semicolons,
 // for instance "FI; OD". These provoke only a warning.
   for (; p != NO_NODE; FORWARD (p)) {
     ignore_superfluous_semicolons (SUB (p));
     if (NEXT (p) != NO_NODE && IS (NEXT (p), SEMI_SYMBOL) && NEXT_NEXT (p) == NO_NODE) {
       diagnostic (A68_WARNING | A68_FORCE_DIAGNOSTICS, NEXT (p), WARNING_SKIPPED_SUPERFLUOUS, ATTRIBUTE (NEXT (p)));
       NEXT (p) = NO_NODE;
     } else if (IS (p, SEMI_SYMBOL) && is_semicolon_less (NEXT (p))) {
       diagnostic (A68_WARNING | A68_FORCE_DIAGNOSTICS, p, WARNING_SKIPPED_SUPERFLUOUS, ATTRIBUTE (p));
       if (PREVIOUS (p) != NO_NODE) {
         NEXT (PREVIOUS (p)) = NEXT (p);
       }
       PREVIOUS (NEXT (p)) = PREVIOUS (p);
     }
   }
 }
 
 //! @brief Driver for the bottom-up parser.
 
 void bottom_up_parser (NODE_T * p)
 {
   if (p != NO_NODE) {
     if (!setjmp (A68_PARSER (bottom_up_crash_exit))) {
       NODE_T *q;
       int error_count_0 = ERROR_COUNT (&A68_JOB);
       ignore_superfluous_semicolons (p);
 // A program is "label sequence; particular program".
       extract_labels (p, SERIAL_CLAUSE);
 // Parse the program itself.
       for (q = p; q != NO_NODE; FORWARD (q)) {
         BOOL_T siga = A68_TRUE;
         if (SUB (q) != NO_NODE) {
           reduce_branch (q, SOME_CLAUSE);
         }
         while (siga) {
           siga = A68_FALSE;
           reduce (q, NO_NOTE, &siga, LABEL, DEFINING_IDENTIFIER, COLON_SYMBOL, STOP);
           reduce (q, NO_NOTE, &siga, LABEL, LABEL, DEFINING_IDENTIFIER, COLON_SYMBOL, STOP);
         }
       }
 // Determine the encompassing enclosed clause.
       for (q = p; q != NO_NODE; FORWARD (q)) {
 #if defined (BUILD_PARALLEL_CLAUSE)
         reduce (q, NO_NOTE, NO_TICK, PARALLEL_CLAUSE, PAR_SYMBOL, COLLATERAL_CLAUSE, STOP);
 #else
         reduce (q, par_clause, NO_TICK, PARALLEL_CLAUSE, PAR_SYMBOL, COLLATERAL_CLAUSE, STOP);
 #endif
         reduce (q, NO_NOTE, NO_TICK, ENCLOSED_CLAUSE, PARALLEL_CLAUSE, STOP);
         reduce (q, NO_NOTE, NO_TICK, ENCLOSED_CLAUSE, CLOSED_CLAUSE, STOP);
         reduce (q, NO_NOTE, NO_TICK, ENCLOSED_CLAUSE, COLLATERAL_CLAUSE, STOP);
         reduce (q, NO_NOTE, NO_TICK, ENCLOSED_CLAUSE, CONDITIONAL_CLAUSE, STOP);
         reduce (q, NO_NOTE, NO_TICK, ENCLOSED_CLAUSE, CASE_CLAUSE, STOP);
         reduce (q, NO_NOTE, NO_TICK, ENCLOSED_CLAUSE, CONFORMITY_CLAUSE, STOP);
         reduce (q, NO_NOTE, NO_TICK, ENCLOSED_CLAUSE, LOOP_CLAUSE, STOP);
       }
 // Try reducing the particular program.
       q = p;
       reduce (q, NO_NOTE, NO_TICK, PARTICULAR_PROGRAM, LABEL, ENCLOSED_CLAUSE, STOP);
       reduce (q, NO_NOTE, NO_TICK, PARTICULAR_PROGRAM, ENCLOSED_CLAUSE, STOP);
       if (SUB (p) == NO_NODE || NEXT (p) != NO_NODE) {
         recover_from_error (p, PARTICULAR_PROGRAM, (BOOL_T) ((ERROR_COUNT (&A68_JOB) - error_count_0) > MAX_ERRORS));
       }
     }
   }
 }
 
 //! @brief Reduce code clause.
 
 void reduce_code_clause (NODE_T * p)
 {
   BOOL_T siga = A68_TRUE;
   while (siga) {
     NODE_T *u;
     siga = A68_FALSE;
     for (u = p; u != NO_NODE; FORWARD (u)) {
       reduce (u, NO_NOTE, &siga, CODE_LIST, CODE_SYMBOL, ROW_CHAR_DENOTATION, STOP);
       reduce (u, NO_NOTE, &siga, CODE_LIST, CODE_LIST, ROW_CHAR_DENOTATION, STOP);
       reduce (u, NO_NOTE, &siga, CODE_LIST, CODE_LIST, COMMA_SYMBOL, ROW_CHAR_DENOTATION, STOP);
       reduce (u, NO_NOTE, &siga, CODE_CLAUSE, CODE_LIST, EDOC_SYMBOL, STOP);
     }
   }
 }
 
 //! @brief Reduce the sub-phrase that starts one level down.
 
 void reduce_branch (NODE_T * q, int expect)
 {
 // If unsuccessful then the routine will at least copy the resulting attribute
 // as the parser can repair some faults. This gives less spurious diagnostics.
   if (q != NO_NODE && SUB (q) != NO_NODE) {
     NODE_T *p = SUB (q), *u = NO_NODE;
     int error_count_0 = ERROR_COUNT (&A68_JOB), error_count_02;
     BOOL_T declarer_pack = A68_FALSE, no_error;
     switch (expect) {
     case STRUCTURE_PACK:
     case PARAMETER_PACK:
     case FORMAL_DECLARERS:
     case UNION_PACK:
     case SPECIFIER:{
         declarer_pack = A68_TRUE;
       }
     default:{
         declarer_pack = A68_FALSE;
       }
     }
 // Sample all info needed to decide whether a bold tag is operator or indicant.
 // Find the meaning of bold tags and quit in case of extra errors.
     extract_indicants (p);
     if (!declarer_pack) {
       extract_priorities (p);
       extract_operators (p);
     }
     error_count_02 = ERROR_COUNT (&A68_JOB);
     elaborate_bold_tags (p);
     if ((ERROR_COUNT (&A68_JOB) - error_count_02) > 0) {
       longjmp (A68_PARSER (bottom_up_crash_exit), 1);
     }
 // Now we can reduce declarers, knowing which bold tags are indicants.
     reduce_declarers (p, expect);
 // Parse the phrase, as appropriate.
     if (expect == CODE_CLAUSE) {
       reduce_code_clause (p);
     } else if (declarer_pack == A68_FALSE) {
       error_count_02 = ERROR_COUNT (&A68_JOB);
       extract_declarations (p);
       if ((ERROR_COUNT (&A68_JOB) - error_count_02) > 0) {
         longjmp (A68_PARSER (bottom_up_crash_exit), 1);
       }
       extract_labels (p, expect);
       for (u = p; u != NO_NODE; FORWARD (u)) {
         if (SUB (u) != NO_NODE) {
           if (IS (u, FORMAT_DELIMITER_SYMBOL)) {
             reduce_branch (u, FORMAT_TEXT);
           } else if (IS (u, FORMAT_OPEN_SYMBOL)) {
             reduce_branch (u, FORMAT_TEXT);
           } else if (IS (u, OPEN_SYMBOL)) {
             if (NEXT (u) != NO_NODE && IS (NEXT (u), THEN_BAR_SYMBOL)) {
               reduce_branch (u, ENQUIRY_CLAUSE);
             } else if (PREVIOUS (u) != NO_NODE && IS (PREVIOUS (u), PAR_SYMBOL)) {
               reduce_branch (u, COLLATERAL_CLAUSE);
             }
           } else if (is_one_of (u, IF_SYMBOL, ELIF_SYMBOL, CASE_SYMBOL, OUSE_SYMBOL, WHILE_SYMBOL, UNTIL_SYMBOL, ELSE_BAR_SYMBOL, ACCO_SYMBOL, STOP)) {
             reduce_branch (u, ENQUIRY_CLAUSE);
           } else if (IS (u, BEGIN_SYMBOL)) {
             reduce_branch (u, SOME_CLAUSE);
           } else if (is_one_of (u, THEN_SYMBOL, ELSE_SYMBOL, OUT_SYMBOL, DO_SYMBOL, ALT_DO_SYMBOL, STOP)) {
             reduce_branch (u, SERIAL_CLAUSE);
           } else if (IS (u, IN_SYMBOL)) {
             reduce_branch (u, COLLATERAL_CLAUSE);
           } else if (IS (u, THEN_BAR_SYMBOL)) {
             reduce_branch (u, SOME_CLAUSE);
           } else if (IS (u, LOOP_CLAUSE)) {
             reduce_branch (u, ENCLOSED_CLAUSE);
           } else if (is_one_of (u, FOR_SYMBOL, FROM_SYMBOL, BY_SYMBOL, TO_SYMBOL, DOWNTO_SYMBOL, STOP)) {
             reduce_branch (u, UNIT);
           }
         }
       }
       reduce_primary_parts (p, expect);
       if (expect != ENCLOSED_CLAUSE) {
         reduce_primaries (p, expect);
         if (expect == FORMAT_TEXT) {
           reduce_format_texts (p);
         } else {
           reduce_secondaries (p);
           reduce_formulae (p);
           reduce_tertiaries (p);
         }
       }
       for (u = p; u != NO_NODE; FORWARD (u)) {
         if (SUB (u) != NO_NODE) {
           if (IS (u, CODE_SYMBOL)) {
             reduce_branch (u, CODE_CLAUSE);
           }
         }
       }
       reduce_right_to_left_constructs (p);
 // Reduce units and declarations.
       reduce_basic_declarations (p);
       reduce_units (p);
       reduce_erroneous_units (p);
       if (expect != UNIT) {
         if (expect == GENERIC_ARGUMENT) {
           reduce_generic_arguments (p);
         } else if (expect == BOUNDS) {
           reduce_bounds (p);
         } else {
           reduce_declaration_lists (p);
           if (expect != DECLARATION_LIST) {
             for (u = p; u != NO_NODE; FORWARD (u)) {
               reduce (u, NO_NOTE, NO_TICK, LABELED_UNIT, LABEL, UNIT, STOP);
               reduce (u, NO_NOTE, NO_TICK, SPECIFIED_UNIT, SPECIFIER, COLON_SYMBOL, UNIT, STOP);
             }
             if (expect == SOME_CLAUSE) {
               expect = serial_or_collateral (p);
             }
             if (expect == SERIAL_CLAUSE) {
               reduce_serial_clauses (p);
             } else if (expect == ENQUIRY_CLAUSE) {
               reduce_enquiry_clauses (p);
             } else if (expect == COLLATERAL_CLAUSE) {
               reduce_collateral_clauses (p);
             } else if (expect == ARGUMENT) {
               reduce_arguments (p);
             }
           }
         }
       }
       reduce_enclosed_clauses (p, expect);
     }
 // Do something if parsing failed.
     if (SUB (p) == NO_NODE || NEXT (p) != NO_NODE) {
       recover_from_error (p, expect, (BOOL_T) ((ERROR_COUNT (&A68_JOB) - error_count_0) > MAX_ERRORS));
       no_error = A68_FALSE;
     } else {
       no_error = A68_TRUE;
     }
     ATTRIBUTE (q) = ATTRIBUTE (p);
     if (no_error) {
       SUB (q) = SUB (p);
     }
   }
 }
 
 //! @brief Driver for reducing declarers.
 
 void reduce_declarers (NODE_T * p, int expect)
 {
   NODE_T *q;
   BOOL_T siga;
 // Reduce lengtheties.
   for (q = p; q != NO_NODE; FORWARD (q)) {
     siga = A68_TRUE;
     reduce (q, NO_NOTE, NO_TICK, LONGETY, LONG_SYMBOL, STOP);
     reduce (q, NO_NOTE, NO_TICK, SHORTETY, SHORT_SYMBOL, STOP);
     while (siga) {
       siga = A68_FALSE;
       reduce (q, NO_NOTE, &siga, LONGETY, LONGETY, LONG_SYMBOL, STOP);
       reduce (q, NO_NOTE, &siga, SHORTETY, SHORTETY, SHORT_SYMBOL, STOP);
     }
   }
 // Reduce indicants.
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, INDICANT, INT_SYMBOL, STOP);
     reduce (q, NO_NOTE, NO_TICK, INDICANT, REAL_SYMBOL, STOP);
     reduce (q, NO_NOTE, NO_TICK, INDICANT, BITS_SYMBOL, STOP);
     reduce (q, NO_NOTE, NO_TICK, INDICANT, BYTES_SYMBOL, STOP);
     reduce (q, NO_NOTE, NO_TICK, INDICANT, COMPLEX_SYMBOL, STOP);
     reduce (q, NO_NOTE, NO_TICK, INDICANT, COMPL_SYMBOL, STOP);
     reduce (q, NO_NOTE, NO_TICK, INDICANT, BOOL_SYMBOL, STOP);
     reduce (q, NO_NOTE, NO_TICK, INDICANT, CHAR_SYMBOL, STOP);
     reduce (q, NO_NOTE, NO_TICK, INDICANT, FORMAT_SYMBOL, STOP);
     reduce (q, NO_NOTE, NO_TICK, INDICANT, STRING_SYMBOL, STOP);
     reduce (q, NO_NOTE, NO_TICK, INDICANT, FILE_SYMBOL, STOP);
     reduce (q, NO_NOTE, NO_TICK, INDICANT, CHANNEL_SYMBOL, STOP);
     reduce (q, NO_NOTE, NO_TICK, INDICANT, SEMA_SYMBOL, STOP);
     reduce (q, NO_NOTE, NO_TICK, INDICANT, PIPE_SYMBOL, STOP);
     reduce (q, NO_NOTE, NO_TICK, INDICANT, SOUND_SYMBOL, STOP);
   }
 // Reduce standard stuff.
   for (q = p; q != NO_NODE; FORWARD (q)) {
     if (whether (q, LONGETY, INDICANT, STOP)) {
       int a;
       if (SUB_NEXT (q) == NO_NODE) {
         diagnostic (A68_SYNTAX_ERROR, NEXT (q), ERROR_EXPECTED, INFO_APPROPRIATE_DECLARER);
         reduce (q, NO_NOTE, NO_TICK, DECLARER, LONGETY, INDICANT, STOP);
       } else {
         a = ATTRIBUTE (SUB_NEXT (q));
         if (a == INT_SYMBOL || a == REAL_SYMBOL || a == BITS_SYMBOL || a == BYTES_SYMBOL || a == COMPLEX_SYMBOL || a == COMPL_SYMBOL) {
           reduce (q, NO_NOTE, NO_TICK, DECLARER, LONGETY, INDICANT, STOP);
         } else {
           diagnostic (A68_SYNTAX_ERROR, NEXT (q), ERROR_EXPECTED, INFO_APPROPRIATE_DECLARER);
           reduce (q, NO_NOTE, NO_TICK, DECLARER, LONGETY, INDICANT, STOP);
         }
       }
     } else if (whether (q, SHORTETY, INDICANT, STOP)) {
       int a;
       if (SUB_NEXT (q) == NO_NODE) {
         diagnostic (A68_SYNTAX_ERROR, NEXT (q), ERROR_EXPECTED, INFO_APPROPRIATE_DECLARER);
         reduce (q, NO_NOTE, NO_TICK, DECLARER, SHORTETY, INDICANT, STOP);
       } else {
         a = ATTRIBUTE (SUB_NEXT (q));
         if (a == INT_SYMBOL || a == REAL_SYMBOL || a == BITS_SYMBOL || a == BYTES_SYMBOL || a == COMPLEX_SYMBOL || a == COMPL_SYMBOL) {
           reduce (q, NO_NOTE, NO_TICK, DECLARER, SHORTETY, INDICANT, STOP);
         } else {
           diagnostic (A68_SYNTAX_ERROR, NEXT (q), ERROR_EXPECTED, INFO_APPROPRIATE_DECLARER);
           reduce (q, NO_NOTE, NO_TICK, DECLARER, LONGETY, INDICANT, STOP);
         }
       }
     }
   }
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, DECLARER, INDICANT, STOP);
   }
 // Reduce declarer lists.
   for (q = p; q != NO_NODE; FORWARD (q)) {
     if (NEXT (q) != NO_NODE && SUB_NEXT (q) != NO_NODE) {
       if (IS (q, STRUCT_SYMBOL)) {
         reduce_branch (NEXT (q), STRUCTURE_PACK);
         reduce (q, NO_NOTE, NO_TICK, DECLARER, STRUCT_SYMBOL, STRUCTURE_PACK, STOP);
       } else if (IS (q, UNION_SYMBOL)) {
         reduce_branch (NEXT (q), UNION_PACK);
         reduce (q, NO_NOTE, NO_TICK, DECLARER, UNION_SYMBOL, UNION_PACK, STOP);
       } else if (IS (q, PROC_SYMBOL)) {
         if (whether (q, PROC_SYMBOL, OPEN_SYMBOL, STOP)) {
           if (!is_formal_bounds (SUB_NEXT (q))) {
             reduce_branch (NEXT (q), FORMAL_DECLARERS);
           }
         }
       } else if (IS (q, OP_SYMBOL)) {
         if (whether (q, OP_SYMBOL, OPEN_SYMBOL, STOP)) {
           if (!is_formal_bounds (SUB_NEXT (q))) {
             reduce_branch (NEXT (q), FORMAL_DECLARERS);
           }
         }
       }
     }
   }
 // Reduce row, proc or op declarers.
   siga = A68_TRUE;
   while (siga) {
     siga = A68_FALSE;
     for (q = p; q != NO_NODE; FORWARD (q)) {
 // FLEX DECL.
       if (whether (q, FLEX_SYMBOL, DECLARER, STOP)) {
         reduce (q, NO_NOTE, &siga, DECLARER, FLEX_SYMBOL, DECLARER, STOP);
       }
 // FLEX [] DECL.
       if (whether (q, FLEX_SYMBOL, SUB_SYMBOL, DECLARER, STOP) && SUB_NEXT (q) != NO_NODE) {
         reduce_branch (NEXT (q), BOUNDS);
         reduce (q, NO_NOTE, &siga, DECLARER, FLEX_SYMBOL, BOUNDS, DECLARER, STOP);
         reduce (q, NO_NOTE, &siga, DECLARER, FLEX_SYMBOL, FORMAL_BOUNDS, DECLARER, STOP);
       }
 // FLEX () DECL.
       if (whether (q, FLEX_SYMBOL, OPEN_SYMBOL, DECLARER, STOP) && SUB_NEXT (q) != NO_NODE) {
         if (!whether (q, FLEX_SYMBOL, OPEN_SYMBOL, DECLARER, COLON_SYMBOL, STOP)) {
           reduce_branch (NEXT (q), BOUNDS);
           reduce (q, NO_NOTE, &siga, DECLARER, FLEX_SYMBOL, BOUNDS, DECLARER, STOP);
           reduce (q, NO_NOTE, &siga, DECLARER, FLEX_SYMBOL, FORMAL_BOUNDS, DECLARER, STOP);
         }
       }
 // [] DECL.
       if (whether (q, SUB_SYMBOL, DECLARER, STOP) && SUB (q) != NO_NODE) {
         reduce_branch (q, BOUNDS);
         reduce (q, NO_NOTE, &siga, DECLARER, BOUNDS, DECLARER, STOP);
         reduce (q, NO_NOTE, &siga, DECLARER, FORMAL_BOUNDS, DECLARER, STOP);
       }
 // () DECL.
       if (whether (q, OPEN_SYMBOL, DECLARER, STOP) && SUB (q) != NO_NODE) {
         if (whether (q, OPEN_SYMBOL, DECLARER, COLON_SYMBOL, STOP)) {
 // Catch e.g. (INT i) () INT:.
           if (is_formal_bounds (SUB (q))) {
             reduce_branch (q, BOUNDS);
             reduce (q, NO_NOTE, &siga, DECLARER, BOUNDS, DECLARER, STOP);
             reduce (q, NO_NOTE, &siga, DECLARER, FORMAL_BOUNDS, DECLARER, STOP);
           }
         } else {
           reduce_branch (q, BOUNDS);
           reduce (q, NO_NOTE, &siga, DECLARER, BOUNDS, DECLARER, STOP);
           reduce (q, NO_NOTE, &siga, DECLARER, FORMAL_BOUNDS, DECLARER, STOP);
         }
       }
     }
 // PROC DECL, PROC () DECL, OP () DECL.
     for (q = p; q != NO_NODE; FORWARD (q)) {
       int a = ATTRIBUTE (q);
       if (a == REF_SYMBOL) {
         reduce (q, NO_NOTE, &siga, DECLARER, REF_SYMBOL, DECLARER, STOP);
       } else if (a == PROC_SYMBOL) {
         reduce (q, NO_NOTE, &siga, DECLARER, PROC_SYMBOL, DECLARER, STOP);
         reduce (q, NO_NOTE, &siga, DECLARER, PROC_SYMBOL, FORMAL_DECLARERS, DECLARER, STOP);
         reduce (q, NO_NOTE, &siga, DECLARER, PROC_SYMBOL, VOID_SYMBOL, STOP);
         reduce (q, NO_NOTE, &siga, DECLARER, PROC_SYMBOL, FORMAL_DECLARERS, VOID_SYMBOL, STOP);
       } else if (a == OP_SYMBOL) {
         reduce (q, NO_NOTE, &siga, OPERATOR_PLAN, OP_SYMBOL, FORMAL_DECLARERS, DECLARER, STOP);
         reduce (q, NO_NOTE, &siga, OPERATOR_PLAN, OP_SYMBOL, FORMAL_DECLARERS, VOID_SYMBOL, STOP);
       }
     }
   }
 // Reduce packs etcetera.
   if (expect == STRUCTURE_PACK) {
     for (q = p; q != NO_NODE; FORWARD (q)) {
       siga = A68_TRUE;
       while (siga) {
         siga = A68_FALSE;
         reduce (q, NO_NOTE, &siga, STRUCTURED_FIELD, DECLARER, IDENTIFIER, STOP);
         reduce (q, NO_NOTE, &siga, STRUCTURED_FIELD, STRUCTURED_FIELD, COMMA_SYMBOL, IDENTIFIER, STOP);
       }
     }
     for (q = p; q != NO_NODE; FORWARD (q)) {
       siga = A68_TRUE;
       while (siga) {
         siga = A68_FALSE;
         reduce (q, NO_NOTE, &siga, STRUCTURED_FIELD_LIST, STRUCTURED_FIELD, STOP);
         reduce (q, NO_NOTE, &siga, STRUCTURED_FIELD_LIST, STRUCTURED_FIELD_LIST, COMMA_SYMBOL, STRUCTURED_FIELD, STOP);
         reduce (q, strange_separator, &siga, STRUCTURED_FIELD_LIST, STRUCTURED_FIELD_LIST, STRUCTURED_FIELD, STOP);
         reduce (q, strange_separator, &siga, STRUCTURED_FIELD_LIST, STRUCTURED_FIELD_LIST, SEMI_SYMBOL, STRUCTURED_FIELD, STOP);
       }
     }
     q = p;
     reduce (q, NO_NOTE, NO_TICK, STRUCTURE_PACK, OPEN_SYMBOL, STRUCTURED_FIELD_LIST, CLOSE_SYMBOL, STOP);
   } else if (expect == PARAMETER_PACK) {
     for (q = p; q != NO_NODE; FORWARD (q)) {
       siga = A68_TRUE;
       while (siga) {
         siga = A68_FALSE;
         reduce (q, NO_NOTE, &siga, PARAMETER, DECLARER, IDENTIFIER, STOP);
         reduce (q, NO_NOTE, &siga, PARAMETER, PARAMETER, COMMA_SYMBOL, IDENTIFIER, STOP);
       }
     }
     for (q = p; q != NO_NODE; FORWARD (q)) {
       siga = A68_TRUE;
       while (siga) {
         siga = A68_FALSE;
         reduce (q, NO_NOTE, &siga, PARAMETER_LIST, PARAMETER, STOP);
         reduce (q, NO_NOTE, &siga, PARAMETER_LIST, PARAMETER_LIST, COMMA_SYMBOL, PARAMETER, STOP);
       }
     }
     q = p;
     reduce (q, NO_NOTE, NO_TICK, PARAMETER_PACK, OPEN_SYMBOL, PARAMETER_LIST, CLOSE_SYMBOL, STOP);
   } else if (expect == FORMAL_DECLARERS) {
     for (q = p; q != NO_NODE; FORWARD (q)) {
       siga = A68_TRUE;
       while (siga) {
         siga = A68_FALSE;
         reduce (q, NO_NOTE, &siga, FORMAL_DECLARERS_LIST, DECLARER, STOP);
         reduce (q, NO_NOTE, &siga, FORMAL_DECLARERS_LIST, FORMAL_DECLARERS_LIST, COMMA_SYMBOL, DECLARER, STOP);
         reduce (q, strange_separator, &siga, FORMAL_DECLARERS_LIST, FORMAL_DECLARERS_LIST, SEMI_SYMBOL, DECLARER, STOP);
         reduce (q, strange_separator, &siga, FORMAL_DECLARERS_LIST, FORMAL_DECLARERS_LIST, DECLARER, STOP);
       }
     }
     q = p;
     reduce (q, NO_NOTE, NO_TICK, FORMAL_DECLARERS, OPEN_SYMBOL, FORMAL_DECLARERS_LIST, CLOSE_SYMBOL, STOP);
   } else if (expect == UNION_PACK) {
     for (q = p; q != NO_NODE; FORWARD (q)) {
       siga = A68_TRUE;
       while (siga) {
         siga = A68_FALSE;
         reduce (q, NO_NOTE, &siga, UNION_DECLARER_LIST, DECLARER, STOP);
         reduce (q, NO_NOTE, &siga, UNION_DECLARER_LIST, VOID_SYMBOL, STOP);
         reduce (q, NO_NOTE, &siga, UNION_DECLARER_LIST, UNION_DECLARER_LIST, COMMA_SYMBOL, DECLARER, STOP);
         reduce (q, NO_NOTE, &siga, UNION_DECLARER_LIST, UNION_DECLARER_LIST, COMMA_SYMBOL, VOID_SYMBOL, STOP);
         reduce (q, strange_separator, &siga, UNION_DECLARER_LIST, UNION_DECLARER_LIST, SEMI_SYMBOL, DECLARER, STOP);
         reduce (q, strange_separator, &siga, UNION_DECLARER_LIST, UNION_DECLARER_LIST, SEMI_SYMBOL, VOID_SYMBOL, STOP);
         reduce (q, strange_separator, &siga, UNION_DECLARER_LIST, UNION_DECLARER_LIST, DECLARER, STOP);
         reduce (q, strange_separator, &siga, UNION_DECLARER_LIST, UNION_DECLARER_LIST, VOID_SYMBOL, STOP);
       }
     }
     q = p;
     reduce (q, NO_NOTE, NO_TICK, UNION_PACK, OPEN_SYMBOL, UNION_DECLARER_LIST, CLOSE_SYMBOL, STOP);
   } else if (expect == SPECIFIER) {
     reduce (p, NO_NOTE, NO_TICK, SPECIFIER, OPEN_SYMBOL, DECLARER, IDENTIFIER, CLOSE_SYMBOL, STOP);
     reduce (p, NO_NOTE, NO_TICK, SPECIFIER, OPEN_SYMBOL, DECLARER, CLOSE_SYMBOL, STOP);
     reduce (p, NO_NOTE, NO_TICK, SPECIFIER, OPEN_SYMBOL, VOID_SYMBOL, CLOSE_SYMBOL, STOP);
   } else {
     for (q = p; q != NO_NODE; FORWARD (q)) {
       if (whether (q, OPEN_SYMBOL, COLON_SYMBOL, STOP) && !(expect == GENERIC_ARGUMENT || expect == BOUNDS)) {
         if (is_one_of (p, IN_SYMBOL, THEN_BAR_SYMBOL, STOP)) {
           reduce_branch (q, SPECIFIER);
         }
       }
       if (whether (q, OPEN_SYMBOL, DECLARER, COLON_SYMBOL, STOP)) {
         reduce_branch (q, PARAMETER_PACK);
       }
       if (whether (q, OPEN_SYMBOL, VOID_SYMBOL, COLON_SYMBOL, STOP)) {
         reduce_branch (q, PARAMETER_PACK);
       }
     }
   }
 }
 
 //! @brief Handle cases that need reducing from right-to-left.
 
 void reduce_right_to_left_constructs (NODE_T * p)
 {
 // Here are cases that need reducing from right-to-left whereas many things
 // can be reduced left-to-right. Assignations are a notable example; one could
 // discuss whether it would not be more natural to write 1 =: k in stead of
 // k := 1. The latter is said to be more natural, or it could be just computing
 // history. Meanwhile we use this routine.
   if (p != NO_NODE) {
     reduce_right_to_left_constructs (NEXT (p));
 // Assignations.
     if (IS (p, TERTIARY)) {
       reduce (p, NO_NOTE, NO_TICK, ASSIGNATION, TERTIARY, ASSIGN_SYMBOL, TERTIARY, STOP);
       reduce (p, NO_NOTE, NO_TICK, ASSIGNATION, TERTIARY, ASSIGN_SYMBOL, IDENTITY_RELATION, STOP);
       reduce (p, NO_NOTE, NO_TICK, ASSIGNATION, TERTIARY, ASSIGN_SYMBOL, AND_FUNCTION, STOP);
       reduce (p, NO_NOTE, NO_TICK, ASSIGNATION, TERTIARY, ASSIGN_SYMBOL, OR_FUNCTION, STOP);
       reduce (p, NO_NOTE, NO_TICK, ASSIGNATION, TERTIARY, ASSIGN_SYMBOL, ROUTINE_TEXT, STOP);
       reduce (p, NO_NOTE, NO_TICK, ASSIGNATION, TERTIARY, ASSIGN_SYMBOL, JUMP, STOP);
       reduce (p, NO_NOTE, NO_TICK, ASSIGNATION, TERTIARY, ASSIGN_SYMBOL, SKIP, STOP);
       reduce (p, NO_NOTE, NO_TICK, ASSIGNATION, TERTIARY, ASSIGN_SYMBOL, ASSIGNATION, STOP);
       reduce (p, NO_NOTE, NO_TICK, ASSIGNATION, TERTIARY, ASSIGN_SYMBOL, CODE_CLAUSE, STOP);
     }
 // Routine texts with parameter pack.
     else if (IS (p, PARAMETER_PACK)) {
       reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, PARAMETER_PACK, DECLARER, COLON_SYMBOL, ASSIGNATION, STOP);
       reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, PARAMETER_PACK, DECLARER, COLON_SYMBOL, IDENTITY_RELATION, STOP);
       reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, PARAMETER_PACK, DECLARER, COLON_SYMBOL, AND_FUNCTION, STOP);
       reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, PARAMETER_PACK, DECLARER, COLON_SYMBOL, OR_FUNCTION, STOP);
       reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, PARAMETER_PACK, DECLARER, COLON_SYMBOL, JUMP, STOP);
       reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, PARAMETER_PACK, DECLARER, COLON_SYMBOL, SKIP, STOP);
       reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, PARAMETER_PACK, DECLARER, COLON_SYMBOL, TERTIARY, STOP);
       reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, PARAMETER_PACK, DECLARER, COLON_SYMBOL, ROUTINE_TEXT, STOP);
       reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, PARAMETER_PACK, DECLARER, COLON_SYMBOL, CODE_CLAUSE, STOP);
       reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, PARAMETER_PACK, VOID_SYMBOL, COLON_SYMBOL, ASSIGNATION, STOP);
       reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, PARAMETER_PACK, VOID_SYMBOL, COLON_SYMBOL, IDENTITY_RELATION, STOP);
       reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, PARAMETER_PACK, VOID_SYMBOL, COLON_SYMBOL, AND_FUNCTION, STOP);
       reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, PARAMETER_PACK, VOID_SYMBOL, COLON_SYMBOL, OR_FUNCTION, STOP);
       reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, PARAMETER_PACK, VOID_SYMBOL, COLON_SYMBOL, JUMP, STOP);
       reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, PARAMETER_PACK, VOID_SYMBOL, COLON_SYMBOL, SKIP, STOP);
       reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, PARAMETER_PACK, VOID_SYMBOL, COLON_SYMBOL, TERTIARY, STOP);
       reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, PARAMETER_PACK, VOID_SYMBOL, COLON_SYMBOL, ROUTINE_TEXT, STOP);
       reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, PARAMETER_PACK, VOID_SYMBOL, COLON_SYMBOL, CODE_CLAUSE, STOP);
     }
 // Routine texts without parameter pack.
     else if (IS (p, DECLARER)) {
       if (!(PREVIOUS (p) != NO_NODE && IS (PREVIOUS (p), PARAMETER_PACK))) {
         reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, DECLARER, COLON_SYMBOL, ASSIGNATION, STOP);
         reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, DECLARER, COLON_SYMBOL, IDENTITY_RELATION, STOP);
         reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, DECLARER, COLON_SYMBOL, AND_FUNCTION, STOP);
         reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, DECLARER, COLON_SYMBOL, OR_FUNCTION, STOP);
         reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, DECLARER, COLON_SYMBOL, JUMP, STOP);
         reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, DECLARER, COLON_SYMBOL, SKIP, STOP);
         reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, DECLARER, COLON_SYMBOL, TERTIARY, STOP);
         reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, DECLARER, COLON_SYMBOL, ROUTINE_TEXT, STOP);
         reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, DECLARER, COLON_SYMBOL, CODE_CLAUSE, STOP);
       }
     } else if (IS (p, VOID_SYMBOL)) {
       if (!(PREVIOUS (p) != NO_NODE && IS (PREVIOUS (p), PARAMETER_PACK))) {
         reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, VOID_SYMBOL, COLON_SYMBOL, ASSIGNATION, STOP);
         reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, VOID_SYMBOL, COLON_SYMBOL, IDENTITY_RELATION, STOP);
         reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, VOID_SYMBOL, COLON_SYMBOL, AND_FUNCTION, STOP);
         reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, VOID_SYMBOL, COLON_SYMBOL, OR_FUNCTION, STOP);
         reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, VOID_SYMBOL, COLON_SYMBOL, JUMP, STOP);
         reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, VOID_SYMBOL, COLON_SYMBOL, SKIP, STOP);
         reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, VOID_SYMBOL, COLON_SYMBOL, TERTIARY, STOP);
         reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, VOID_SYMBOL, COLON_SYMBOL, ROUTINE_TEXT, STOP);
         reduce (p, NO_NOTE, NO_TICK, ROUTINE_TEXT, VOID_SYMBOL, COLON_SYMBOL, CODE_CLAUSE, STOP);
       }
     }
   }
 }
 
 //! @brief Reduce primary elements.
 
 void reduce_primary_parts (NODE_T * p, int expect)
 {
   NODE_T *q = p;
   for (; q != NO_NODE; FORWARD (q)) {
     if (whether (q, IDENTIFIER, OF_SYMBOL, STOP)) {
       ATTRIBUTE (q) = FIELD_IDENTIFIER;
     }
     reduce (q, NO_NOTE, NO_TICK, ENVIRON_NAME, ENVIRON_SYMBOL, ROW_CHAR_DENOTATION, STOP);
     reduce (q, NO_NOTE, NO_TICK, NIHIL, NIL_SYMBOL, STOP);
     reduce (q, NO_NOTE, NO_TICK, SKIP, SKIP_SYMBOL, STOP);
     reduce (q, NO_NOTE, NO_TICK, SELECTOR, FIELD_IDENTIFIER, OF_SYMBOL, STOP);
 // JUMPs without GOTO are resolved later.
     reduce (q, NO_NOTE, NO_TICK, JUMP, GOTO_SYMBOL, IDENTIFIER, STOP);
     reduce (q, NO_NOTE, NO_TICK, DENOTATION, LONGETY, INT_DENOTATION, STOP);
     reduce (q, NO_NOTE, NO_TICK, DENOTATION, LONGETY, REAL_DENOTATION, STOP);
     reduce (q, NO_NOTE, NO_TICK, DENOTATION, LONGETY, BITS_DENOTATION, STOP);
     reduce (q, NO_NOTE, NO_TICK, DENOTATION, SHORTETY, INT_DENOTATION, STOP);
     reduce (q, NO_NOTE, NO_TICK, DENOTATION, SHORTETY, REAL_DENOTATION, STOP);
     reduce (q, NO_NOTE, NO_TICK, DENOTATION, SHORTETY, BITS_DENOTATION, STOP);
     reduce (q, NO_NOTE, NO_TICK, DENOTATION, INT_DENOTATION, STOP);
     reduce (q, NO_NOTE, NO_TICK, DENOTATION, REAL_DENOTATION, STOP);
     reduce (q, NO_NOTE, NO_TICK, DENOTATION, BITS_DENOTATION, STOP);
     reduce (q, NO_NOTE, NO_TICK, DENOTATION, ROW_CHAR_DENOTATION, STOP);
     reduce (q, NO_NOTE, NO_TICK, DENOTATION, TRUE_SYMBOL, STOP);
     reduce (q, NO_NOTE, NO_TICK, DENOTATION, FALSE_SYMBOL, STOP);
     reduce (q, NO_NOTE, NO_TICK, DENOTATION, EMPTY_SYMBOL, STOP);
     if (expect == SERIAL_CLAUSE || expect == ENQUIRY_CLAUSE || expect == SOME_CLAUSE) {
       BOOL_T siga = A68_TRUE;
       while (siga) {
         siga = A68_FALSE;
         reduce (q, NO_NOTE, &siga, LABEL, DEFINING_IDENTIFIER, COLON_SYMBOL, STOP);
         reduce (q, NO_NOTE, &siga, LABEL, LABEL, DEFINING_IDENTIFIER, COLON_SYMBOL, STOP);
       }
     }
   }
   for (q = p; q != NO_NODE; FORWARD (q)) {
 #if defined (BUILD_PARALLEL_CLAUSE)
     reduce (q, NO_NOTE, NO_TICK, PARALLEL_CLAUSE, PAR_SYMBOL, COLLATERAL_CLAUSE, STOP);
 #else
     reduce (q, par_clause, NO_TICK, PARALLEL_CLAUSE, PAR_SYMBOL, COLLATERAL_CLAUSE, STOP);
 #endif
     reduce (q, NO_NOTE, NO_TICK, ENCLOSED_CLAUSE, PARALLEL_CLAUSE, STOP);
     reduce (q, NO_NOTE, NO_TICK, ENCLOSED_CLAUSE, CLOSED_CLAUSE, STOP);
     reduce (q, NO_NOTE, NO_TICK, ENCLOSED_CLAUSE, COLLATERAL_CLAUSE, STOP);
     reduce (q, NO_NOTE, NO_TICK, ENCLOSED_CLAUSE, CONDITIONAL_CLAUSE, STOP);
     reduce (q, NO_NOTE, NO_TICK, ENCLOSED_CLAUSE, CASE_CLAUSE, STOP);
     reduce (q, NO_NOTE, NO_TICK, ENCLOSED_CLAUSE, CONFORMITY_CLAUSE, STOP);
     reduce (q, NO_NOTE, NO_TICK, ENCLOSED_CLAUSE, LOOP_CLAUSE, STOP);
   }
 }
 
 //! @brief Reduce primaries completely.
 
 void reduce_primaries (NODE_T * p, int expect)
 {
   NODE_T *q = p;
   while (q != NO_NODE) {
     BOOL_T fwd = A68_TRUE, siga;
 // Primaries excepts call and slice.
     reduce (q, NO_NOTE, NO_TICK, PRIMARY, IDENTIFIER, STOP);
     reduce (q, NO_NOTE, NO_TICK, PRIMARY, DENOTATION, STOP);
     reduce (q, NO_NOTE, NO_TICK, CAST, DECLARER, ENCLOSED_CLAUSE, STOP);
     reduce (q, NO_NOTE, NO_TICK, CAST, VOID_SYMBOL, ENCLOSED_CLAUSE, STOP);
     reduce (q, NO_NOTE, NO_TICK, ASSERTION, ASSERT_SYMBOL, ENCLOSED_CLAUSE, STOP);
     reduce (q, NO_NOTE, NO_TICK, PRIMARY, CAST, STOP);
     reduce (q, NO_NOTE, NO_TICK, PRIMARY, ENCLOSED_CLAUSE, STOP);
     reduce (q, NO_NOTE, NO_TICK, PRIMARY, FORMAT_TEXT, STOP);
 // Call and slice.
     siga = A68_TRUE;
     while (siga) {
       NODE_T *x = NEXT (q);
       siga = A68_FALSE;
       if (IS (q, PRIMARY) && x != NO_NODE) {
         if (IS (x, OPEN_SYMBOL)) {
           reduce_branch (NEXT (q), GENERIC_ARGUMENT);
           reduce (q, NO_NOTE, &siga, SPECIFICATION, PRIMARY, GENERIC_ARGUMENT, STOP);
           reduce (q, NO_NOTE, &siga, PRIMARY, SPECIFICATION, STOP);
         } else if (IS (x, SUB_SYMBOL)) {
           reduce_branch (NEXT (q), GENERIC_ARGUMENT);
           reduce (q, NO_NOTE, &siga, SPECIFICATION, PRIMARY, GENERIC_ARGUMENT, STOP);
           reduce (q, NO_NOTE, &siga, PRIMARY, SPECIFICATION, STOP);
         }
       }
     }
 // Now that call and slice are known, reduce remaining ( .. ).
     if (IS (q, OPEN_SYMBOL) && SUB (q) != NO_NODE) {
       reduce_branch (q, SOME_CLAUSE);
       reduce (q, NO_NOTE, NO_TICK, ENCLOSED_CLAUSE, CLOSED_CLAUSE, STOP);
       reduce (q, NO_NOTE, NO_TICK, ENCLOSED_CLAUSE, COLLATERAL_CLAUSE, STOP);
       reduce (q, NO_NOTE, NO_TICK, ENCLOSED_CLAUSE, CONDITIONAL_CLAUSE, STOP);
       reduce (q, NO_NOTE, NO_TICK, ENCLOSED_CLAUSE, CASE_CLAUSE, STOP);
       reduce (q, NO_NOTE, NO_TICK, ENCLOSED_CLAUSE, CONFORMITY_CLAUSE, STOP);
       if (PREVIOUS (q) != NO_NODE) {
         BACKWARD (q);
         fwd = A68_FALSE;
       }
     }
 // Format text items.
     if (expect == FORMAT_TEXT) {
       NODE_T *r;
       for (r = p; r != NO_NODE; FORWARD (r)) {
         reduce (r, NO_NOTE, NO_TICK, DYNAMIC_REPLICATOR, FORMAT_ITEM_N, ENCLOSED_CLAUSE, STOP);
         reduce (r, NO_NOTE, NO_TICK, GENERAL_PATTERN, FORMAT_ITEM_G, ENCLOSED_CLAUSE, STOP);
         reduce (r, NO_NOTE, NO_TICK, GENERAL_PATTERN, FORMAT_ITEM_H, ENCLOSED_CLAUSE, STOP);
         reduce (r, NO_NOTE, NO_TICK, FORMAT_PATTERN, FORMAT_ITEM_F, ENCLOSED_CLAUSE, STOP);
       }
     }
     if (fwd) {
       FORWARD (q);
     }
   }
 }
 
 //! @brief Enforce that ambiguous patterns are separated by commas.
 
 void ambiguous_patterns (NODE_T * p)
 {
 // Example: printf (($+d.2d +d.2d$, 1, 2)) can produce either "+1.00 +2.00" or
 // "+1+002.00". A comma must be supplied to resolve the ambiguity.
 // 
 // The obvious thing would be to weave this into the syntax, letting the BU parser
 // sort it out. But the C-style patterns do not suffer from Algol 68 pattern
 // ambiguity, so by solving it this way we maximise freedom in writing the patterns
 // as we want without introducing two "kinds" of patterns, and so we have shorter
 // routines for implementing formatted transput. This is a pragmatic system.
   NODE_T *q, *last_pat = NO_NODE;
   for (q = p; q != NO_NODE; FORWARD (q)) {
     switch (ATTRIBUTE (q)) {
     case INTEGRAL_PATTERN:     // These are the potentially ambiguous patterns
     case REAL_PATTERN:
     case COMPLEX_PATTERN:
     case BITS_PATTERN:
       {
         if (last_pat != NO_NODE) {
           diagnostic (A68_SYNTAX_ERROR, q, ERROR_COMMA_MUST_SEPARATE, ATTRIBUTE (last_pat), ATTRIBUTE (q));
         }
         last_pat = q;
         break;
       }
     case COMMA_SYMBOL:
       {
         last_pat = NO_NODE;
         break;
       }
     }
   }
 }
 
 //! @brief Reduce format texts completely.
 
 void reduce_c_pattern (NODE_T * p, int pr, int let)
 {
   NODE_T *q;
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, pr, FORMAT_ITEM_ESCAPE, let, STOP);
     reduce (q, NO_NOTE, NO_TICK, pr, FORMAT_ITEM_ESCAPE, FORMAT_ITEM_POINT, REPLICATOR, let, STOP);
     reduce (q, NO_NOTE, NO_TICK, pr, FORMAT_ITEM_ESCAPE, REPLICATOR, let, STOP);
     reduce (q, NO_NOTE, NO_TICK, pr, FORMAT_ITEM_ESCAPE, REPLICATOR, FORMAT_ITEM_POINT, REPLICATOR, let, STOP);
     reduce (q, NO_NOTE, NO_TICK, pr, FORMAT_ITEM_ESCAPE, FORMAT_ITEM_PLUS, let, STOP);
     reduce (q, NO_NOTE, NO_TICK, pr, FORMAT_ITEM_ESCAPE, FORMAT_ITEM_PLUS, FORMAT_ITEM_POINT, REPLICATOR, let, STOP);
     reduce (q, NO_NOTE, NO_TICK, pr, FORMAT_ITEM_ESCAPE, FORMAT_ITEM_PLUS, REPLICATOR, let, STOP);
     reduce (q, NO_NOTE, NO_TICK, pr, FORMAT_ITEM_ESCAPE, FORMAT_ITEM_PLUS, REPLICATOR, FORMAT_ITEM_POINT, REPLICATOR, let, STOP);
     reduce (q, NO_NOTE, NO_TICK, pr, FORMAT_ITEM_ESCAPE, FORMAT_ITEM_MINUS, let, STOP);
     reduce (q, NO_NOTE, NO_TICK, pr, FORMAT_ITEM_ESCAPE, FORMAT_ITEM_MINUS, FORMAT_ITEM_POINT, REPLICATOR, let, STOP);
     reduce (q, NO_NOTE, NO_TICK, pr, FORMAT_ITEM_ESCAPE, FORMAT_ITEM_MINUS, REPLICATOR, let, STOP);
     reduce (q, NO_NOTE, NO_TICK, pr, FORMAT_ITEM_ESCAPE, FORMAT_ITEM_MINUS, REPLICATOR, FORMAT_ITEM_POINT, REPLICATOR, let, STOP);
     reduce (q, NO_NOTE, NO_TICK, pr, FORMAT_ITEM_ESCAPE, FORMAT_ITEM_MINUS, FORMAT_ITEM_PLUS, let, STOP);
     reduce (q, NO_NOTE, NO_TICK, pr, FORMAT_ITEM_ESCAPE, FORMAT_ITEM_MINUS, FORMAT_ITEM_PLUS, FORMAT_ITEM_POINT, REPLICATOR, let, STOP);
     reduce (q, NO_NOTE, NO_TICK, pr, FORMAT_ITEM_ESCAPE, FORMAT_ITEM_MINUS, FORMAT_ITEM_PLUS, REPLICATOR, let, STOP);
     reduce (q, NO_NOTE, NO_TICK, pr, FORMAT_ITEM_ESCAPE, FORMAT_ITEM_MINUS, FORMAT_ITEM_PLUS, REPLICATOR, FORMAT_ITEM_POINT, REPLICATOR, let, STOP);
   }
 }
 
 //! @brief Reduce format texts completely.
 
 void reduce_format_texts (NODE_T * p)
 {
   NODE_T *q;
 // Replicators.
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, REPLICATOR, STATIC_REPLICATOR, STOP);
     reduce (q, NO_NOTE, NO_TICK, REPLICATOR, DYNAMIC_REPLICATOR, STOP);
   }
 // "OTHER" patterns.
   reduce_c_pattern (p, BITS_C_PATTERN, FORMAT_ITEM_B);
   reduce_c_pattern (p, BITS_C_PATTERN, FORMAT_ITEM_O);
   reduce_c_pattern (p, BITS_C_PATTERN, FORMAT_ITEM_X);
   reduce_c_pattern (p, CHAR_C_PATTERN, FORMAT_ITEM_C);
   reduce_c_pattern (p, FIXED_C_PATTERN, FORMAT_ITEM_F);
   reduce_c_pattern (p, FLOAT_C_PATTERN, FORMAT_ITEM_E);
   reduce_c_pattern (p, GENERAL_C_PATTERN, FORMAT_ITEM_G);
   reduce_c_pattern (p, INTEGRAL_C_PATTERN, FORMAT_ITEM_D);
   reduce_c_pattern (p, INTEGRAL_C_PATTERN, FORMAT_ITEM_I);
   reduce_c_pattern (p, STRING_C_PATTERN, FORMAT_ITEM_S);
 // Radix frames.
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, RADIX_FRAME, REPLICATOR, FORMAT_ITEM_R, STOP);
   }
 // Insertions.
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, INSERTION, FORMAT_ITEM_X, STOP);
     reduce (q, NO_NOTE, NO_TICK, INSERTION, FORMAT_ITEM_Y, STOP);
     reduce (q, NO_NOTE, NO_TICK, INSERTION, FORMAT_ITEM_L, STOP);
     reduce (q, NO_NOTE, NO_TICK, INSERTION, FORMAT_ITEM_P, STOP);
     reduce (q, NO_NOTE, NO_TICK, INSERTION, FORMAT_ITEM_Q, STOP);
     reduce (q, NO_NOTE, NO_TICK, INSERTION, FORMAT_ITEM_K, STOP);
     reduce (q, NO_NOTE, NO_TICK, INSERTION, LITERAL, STOP);
   }
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, INSERTION, REPLICATOR, INSERTION, STOP);
   }
   for (q = p; q != NO_NODE; FORWARD (q)) {
     BOOL_T siga = A68_TRUE;
     while (siga) {
       siga = A68_FALSE;
       reduce (q, NO_NOTE, &siga, INSERTION, INSERTION, INSERTION, STOP);
     }
   }
 // Replicated suppressible frames.
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, FORMAT_A_FRAME, REPLICATOR, FORMAT_ITEM_S, FORMAT_ITEM_A, STOP);
     reduce (q, NO_NOTE, NO_TICK, FORMAT_Z_FRAME, REPLICATOR, FORMAT_ITEM_S, FORMAT_ITEM_Z, STOP);
     reduce (q, NO_NOTE, NO_TICK, FORMAT_D_FRAME, REPLICATOR, FORMAT_ITEM_S, FORMAT_ITEM_D, STOP);
   }
 // Suppressible frames.
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, FORMAT_A_FRAME, FORMAT_ITEM_S, FORMAT_ITEM_A, STOP);
     reduce (q, NO_NOTE, NO_TICK, FORMAT_Z_FRAME, FORMAT_ITEM_S, FORMAT_ITEM_Z, STOP);
     reduce (q, NO_NOTE, NO_TICK, FORMAT_D_FRAME, FORMAT_ITEM_S, FORMAT_ITEM_D, STOP);
     reduce (q, NO_NOTE, NO_TICK, FORMAT_E_FRAME, FORMAT_ITEM_S, FORMAT_ITEM_E, STOP);
     reduce (q, NO_NOTE, NO_TICK, FORMAT_POINT_FRAME, FORMAT_ITEM_S, FORMAT_ITEM_POINT, STOP);
     reduce (q, NO_NOTE, NO_TICK, FORMAT_I_FRAME, FORMAT_ITEM_S, FORMAT_ITEM_I, STOP);
   }
 // Replicated frames.
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, FORMAT_A_FRAME, REPLICATOR, FORMAT_ITEM_A, STOP);
     reduce (q, NO_NOTE, NO_TICK, FORMAT_Z_FRAME, REPLICATOR, FORMAT_ITEM_Z, STOP);
     reduce (q, NO_NOTE, NO_TICK, FORMAT_D_FRAME, REPLICATOR, FORMAT_ITEM_D, STOP);
   }
 // Frames.
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, FORMAT_A_FRAME, FORMAT_ITEM_A, STOP);
     reduce (q, NO_NOTE, NO_TICK, FORMAT_Z_FRAME, FORMAT_ITEM_Z, STOP);
     reduce (q, NO_NOTE, NO_TICK, FORMAT_D_FRAME, FORMAT_ITEM_D, STOP);
     reduce (q, NO_NOTE, NO_TICK, FORMAT_E_FRAME, FORMAT_ITEM_E, STOP);
     reduce (q, NO_NOTE, NO_TICK, FORMAT_POINT_FRAME, FORMAT_ITEM_POINT, STOP);
     reduce (q, NO_NOTE, NO_TICK, FORMAT_I_FRAME, FORMAT_ITEM_I, STOP);
   }
 // Frames with an insertion.
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, FORMAT_A_FRAME, INSERTION, FORMAT_A_FRAME, STOP);
     reduce (q, NO_NOTE, NO_TICK, FORMAT_Z_FRAME, INSERTION, FORMAT_Z_FRAME, STOP);
     reduce (q, NO_NOTE, NO_TICK, FORMAT_D_FRAME, INSERTION, FORMAT_D_FRAME, STOP);
     reduce (q, NO_NOTE, NO_TICK, FORMAT_E_FRAME, INSERTION, FORMAT_E_FRAME, STOP);
     reduce (q, NO_NOTE, NO_TICK, FORMAT_POINT_FRAME, INSERTION, FORMAT_POINT_FRAME, STOP);
     reduce (q, NO_NOTE, NO_TICK, FORMAT_I_FRAME, INSERTION, FORMAT_I_FRAME, STOP);
   }
 // String patterns.
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, STRING_PATTERN, REPLICATOR, FORMAT_A_FRAME, STOP);
   }
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, STRING_PATTERN, FORMAT_A_FRAME, STOP);
   }
   for (q = p; q != NO_NODE; FORWARD (q)) {
     BOOL_T siga = A68_TRUE;
     while (siga) {
       siga = A68_FALSE;
       reduce (q, NO_NOTE, &siga, STRING_PATTERN, STRING_PATTERN, STRING_PATTERN, STOP);
       reduce (q, NO_NOTE, &siga, STRING_PATTERN, STRING_PATTERN, INSERTION, STRING_PATTERN, STOP);
     }
   }
 // Integral moulds.
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, INTEGRAL_MOULD, FORMAT_Z_FRAME, STOP);
     reduce (q, NO_NOTE, NO_TICK, INTEGRAL_MOULD, FORMAT_D_FRAME, STOP);
   }
   for (q = p; q != NO_NODE; FORWARD (q)) {
     BOOL_T siga = A68_TRUE;
     while (siga) {
       siga = A68_FALSE;
       reduce (q, NO_NOTE, &siga, INTEGRAL_MOULD, INTEGRAL_MOULD, INTEGRAL_MOULD, STOP);
       reduce (q, NO_NOTE, &siga, INTEGRAL_MOULD, INTEGRAL_MOULD, INSERTION, STOP);
     }
   }
 // Sign moulds.
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, SIGN_MOULD, INTEGRAL_MOULD, FORMAT_ITEM_PLUS, STOP);
     reduce (q, NO_NOTE, NO_TICK, SIGN_MOULD, INTEGRAL_MOULD, FORMAT_ITEM_MINUS, STOP);
   }
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, SIGN_MOULD, FORMAT_ITEM_PLUS, STOP);
     reduce (q, NO_NOTE, NO_TICK, SIGN_MOULD, FORMAT_ITEM_MINUS, STOP);
   }
 // Exponent frames.
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, EXPONENT_FRAME, FORMAT_E_FRAME, SIGN_MOULD, INTEGRAL_MOULD, STOP);
     reduce (q, NO_NOTE, NO_TICK, EXPONENT_FRAME, FORMAT_E_FRAME, INTEGRAL_MOULD, STOP);
   }
 // Real patterns.
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, REAL_PATTERN, SIGN_MOULD, INTEGRAL_MOULD, FORMAT_POINT_FRAME, INTEGRAL_MOULD, EXPONENT_FRAME, STOP);
     reduce (q, NO_NOTE, NO_TICK, REAL_PATTERN, SIGN_MOULD, INTEGRAL_MOULD, FORMAT_POINT_FRAME, INTEGRAL_MOULD, STOP);
     reduce (q, NO_NOTE, NO_TICK, REAL_PATTERN, SIGN_MOULD, INTEGRAL_MOULD, FORMAT_POINT_FRAME, EXPONENT_FRAME, STOP);
     reduce (q, NO_NOTE, NO_TICK, REAL_PATTERN, SIGN_MOULD, INTEGRAL_MOULD, FORMAT_POINT_FRAME, STOP);
   }
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, REAL_PATTERN, SIGN_MOULD, FORMAT_POINT_FRAME, INTEGRAL_MOULD, EXPONENT_FRAME, STOP);
     reduce (q, NO_NOTE, NO_TICK, REAL_PATTERN, SIGN_MOULD, FORMAT_POINT_FRAME, INTEGRAL_MOULD, STOP);
     reduce (q, NO_NOTE, NO_TICK, REAL_PATTERN, SIGN_MOULD, FORMAT_POINT_FRAME, EXPONENT_FRAME, STOP);
     reduce (q, NO_NOTE, NO_TICK, REAL_PATTERN, SIGN_MOULD, FORMAT_POINT_FRAME, STOP);
   }
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, REAL_PATTERN, INTEGRAL_MOULD, FORMAT_POINT_FRAME, INTEGRAL_MOULD, EXPONENT_FRAME, STOP);
     reduce (q, NO_NOTE, NO_TICK, REAL_PATTERN, INTEGRAL_MOULD, FORMAT_POINT_FRAME, INTEGRAL_MOULD, STOP);
     reduce (q, NO_NOTE, NO_TICK, REAL_PATTERN, INTEGRAL_MOULD, FORMAT_POINT_FRAME, EXPONENT_FRAME, STOP);
     reduce (q, NO_NOTE, NO_TICK, REAL_PATTERN, INTEGRAL_MOULD, FORMAT_POINT_FRAME, STOP);
     reduce (q, NO_NOTE, NO_TICK, REAL_PATTERN, FORMAT_POINT_FRAME, INTEGRAL_MOULD, EXPONENT_FRAME, STOP);
     reduce (q, NO_NOTE, NO_TICK, REAL_PATTERN, FORMAT_POINT_FRAME, INTEGRAL_MOULD, STOP);
   }
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, REAL_PATTERN, SIGN_MOULD, INTEGRAL_MOULD, EXPONENT_FRAME, STOP);
     reduce (q, NO_NOTE, NO_TICK, REAL_PATTERN, INTEGRAL_MOULD, EXPONENT_FRAME, STOP);
   }
 // Complex patterns.
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, COMPLEX_PATTERN, REAL_PATTERN, FORMAT_I_FRAME, REAL_PATTERN, STOP);
   }
 // Bits patterns.
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, BITS_PATTERN, RADIX_FRAME, INTEGRAL_MOULD, STOP);
   }
 // Integral patterns.
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, INTEGRAL_PATTERN, SIGN_MOULD, INTEGRAL_MOULD, STOP);
     reduce (q, NO_NOTE, NO_TICK, INTEGRAL_PATTERN, INTEGRAL_MOULD, STOP);
   }
 // Patterns.
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, BOOLEAN_PATTERN, FORMAT_ITEM_B, COLLECTION, STOP);
     reduce (q, NO_NOTE, NO_TICK, CHOICE_PATTERN, FORMAT_ITEM_C, COLLECTION, STOP);
   }
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, BOOLEAN_PATTERN, FORMAT_ITEM_B, STOP);
     reduce (q, NO_NOTE, NO_TICK, GENERAL_PATTERN, FORMAT_ITEM_G, STOP);
     reduce (q, NO_NOTE, NO_TICK, GENERAL_PATTERN, FORMAT_ITEM_H, STOP);
   }
   ambiguous_patterns (p);
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, a68_extension, NO_TICK, A68_PATTERN, BITS_C_PATTERN, STOP);
     reduce (q, a68_extension, NO_TICK, A68_PATTERN, CHAR_C_PATTERN, STOP);
     reduce (q, a68_extension, NO_TICK, A68_PATTERN, FIXED_C_PATTERN, STOP);
     reduce (q, a68_extension, NO_TICK, A68_PATTERN, FLOAT_C_PATTERN, STOP);
     reduce (q, a68_extension, NO_TICK, A68_PATTERN, GENERAL_C_PATTERN, STOP);
     reduce (q, a68_extension, NO_TICK, A68_PATTERN, INTEGRAL_C_PATTERN, STOP);
     reduce (q, a68_extension, NO_TICK, A68_PATTERN, STRING_C_PATTERN, STOP);
     reduce (q, NO_NOTE, NO_TICK, A68_PATTERN, BITS_PATTERN, STOP);
     reduce (q, NO_NOTE, NO_TICK, A68_PATTERN, BOOLEAN_PATTERN, STOP);
     reduce (q, NO_NOTE, NO_TICK, A68_PATTERN, CHOICE_PATTERN, STOP);
     reduce (q, NO_NOTE, NO_TICK, A68_PATTERN, COMPLEX_PATTERN, STOP);
     reduce (q, NO_NOTE, NO_TICK, A68_PATTERN, FORMAT_PATTERN, STOP);
     reduce (q, NO_NOTE, NO_TICK, A68_PATTERN, GENERAL_PATTERN, STOP);
     reduce (q, NO_NOTE, NO_TICK, A68_PATTERN, INTEGRAL_PATTERN, STOP);
     reduce (q, NO_NOTE, NO_TICK, A68_PATTERN, REAL_PATTERN, STOP);
     reduce (q, NO_NOTE, NO_TICK, A68_PATTERN, STRING_PATTERN, STOP);
   }
 // Pictures.
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, PICTURE, INSERTION, STOP);
     reduce (q, NO_NOTE, NO_TICK, PICTURE, A68_PATTERN, STOP);
     reduce (q, NO_NOTE, NO_TICK, PICTURE, COLLECTION, STOP);
     reduce (q, NO_NOTE, NO_TICK, PICTURE, REPLICATOR, COLLECTION, STOP);
   }
 // Picture lists.
   for (q = p; q != NO_NODE; FORWARD (q)) {
     if (IS (q, PICTURE)) {
       BOOL_T siga = A68_TRUE;
       reduce (q, NO_NOTE, NO_TICK, PICTURE_LIST, PICTURE, STOP);
       while (siga) {
         siga = A68_FALSE;
         reduce (q, NO_NOTE, &siga, PICTURE_LIST, PICTURE_LIST, COMMA_SYMBOL, PICTURE, STOP);
 // We filtered ambiguous patterns, so commas may be omitted 
         reduce (q, NO_NOTE, &siga, PICTURE_LIST, PICTURE_LIST, PICTURE, STOP);
       }
     }
   }
 }
 
 //! @brief Reduce secondaries completely.
 
 void reduce_secondaries (NODE_T * p)
 {
   NODE_T *q;
   BOOL_T siga;
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, SECONDARY, PRIMARY, STOP);
     reduce (q, NO_NOTE, NO_TICK, GENERATOR, LOC_SYMBOL, DECLARER, STOP);
     reduce (q, NO_NOTE, NO_TICK, GENERATOR, HEAP_SYMBOL, DECLARER, STOP);
     reduce (q, NO_NOTE, NO_TICK, GENERATOR, NEW_SYMBOL, DECLARER, STOP);
     reduce (q, NO_NOTE, NO_TICK, SECONDARY, GENERATOR, STOP);
   }
   siga = A68_TRUE;
   while (siga) {
     siga = A68_FALSE;
     for (q = p; NEXT (q) != NO_NODE; FORWARD (q)) {
       ;
     }
     for (; q != NO_NODE; BACKWARD (q)) {
       reduce (q, NO_NOTE, &siga, SELECTION, SELECTOR, SECONDARY, STOP);
       reduce (q, NO_NOTE, &siga, SECONDARY, SELECTION, STOP);
     }
   }
 }
 
 //! @brief Whether "q" is an operator with priority "k".
 
 int operator_with_priority (NODE_T * q, int k)
 {
   return NEXT (q) != NO_NODE && ATTRIBUTE (NEXT (q)) == OPERATOR && PRIO (INFO (NEXT (q))) == k;
 }
 
 //! @brief Reduce formulae.
 
 void reduce_formulae (NODE_T * p)
 {
   NODE_T *q = p;
   int priority;
   while (q != NO_NODE) {
     if (is_one_of (q, OPERATOR, SECONDARY, STOP)) {
       q = reduce_dyadic (q, STOP);
     } else {
       FORWARD (q);
     }
   }
 // Reduce the expression.
   for (priority = MAX_PRIORITY; priority >= 0; priority--) {
     for (q = p; q != NO_NODE; FORWARD (q)) {
       if (operator_with_priority (q, priority)) {
         BOOL_T siga = A68_FALSE;
         NODE_T *op = NEXT (q);
         if (IS (q, SECONDARY)) {
           reduce (q, NO_NOTE, &siga, FORMULA, SECONDARY, OPERATOR, SECONDARY, STOP);
           reduce (q, NO_NOTE, &siga, FORMULA, SECONDARY, OPERATOR, MONADIC_FORMULA, STOP);
           reduce (q, NO_NOTE, &siga, FORMULA, SECONDARY, OPERATOR, FORMULA, STOP);
         } else if (IS (q, MONADIC_FORMULA)) {
           reduce (q, NO_NOTE, &siga, FORMULA, MONADIC_FORMULA, OPERATOR, SECONDARY, STOP);
           reduce (q, NO_NOTE, &siga, FORMULA, MONADIC_FORMULA, OPERATOR, MONADIC_FORMULA, STOP);
           reduce (q, NO_NOTE, &siga, FORMULA, MONADIC_FORMULA, OPERATOR, FORMULA, STOP);
         }
         if (priority == 0 && siga) {
           diagnostic (A68_SYNTAX_ERROR, op, ERROR_NO_PRIORITY);
         }
         siga = A68_TRUE;
         while (siga) {
           NODE_T *op2 = NEXT (q);
           siga = A68_FALSE;
           if (operator_with_priority (q, priority)) {
             reduce (q, NO_NOTE, &siga, FORMULA, FORMULA, OPERATOR, SECONDARY, STOP);
           }
           if (operator_with_priority (q, priority)) {
             reduce (q, NO_NOTE, &siga, FORMULA, FORMULA, OPERATOR, MONADIC_FORMULA, STOP);
           }
           if (operator_with_priority (q, priority)) {
             reduce (q, NO_NOTE, &siga, FORMULA, FORMULA, OPERATOR, FORMULA, STOP);
           }
           if (priority == 0 && siga) {
             diagnostic (A68_SYNTAX_ERROR, op2, ERROR_NO_PRIORITY);
           }
         }
       }
     }
   }
 }
 
 //! @brief Reduce dyadic expressions.
 
 NODE_T *reduce_dyadic (NODE_T * p, int u)
 {
 // We work inside out - higher priority expressions get reduced first.
   if (u > MAX_PRIORITY) {
     if (p == NO_NODE) {
       return NO_NODE;
     } else if (IS (p, OPERATOR)) {
 // Reduce monadic formulas.
       NODE_T *q = p;
       BOOL_T siga;
       do {
         PRIO (INFO (q)) = 10;
         siga = (BOOL_T) ((NEXT (q) != NO_NODE) && (IS (NEXT (q), OPERATOR)));
         if (siga) {
           FORWARD (q);
         }
       } while (siga);
       reduce (q, NO_NOTE, NO_TICK, MONADIC_FORMULA, OPERATOR, SECONDARY, STOP);
       while (q != p) {
         BACKWARD (q);
         reduce (q, NO_NOTE, NO_TICK, MONADIC_FORMULA, OPERATOR, MONADIC_FORMULA, STOP);
       }
     }
     FORWARD (p);
   } else {
     p = reduce_dyadic (p, u + 1);
     while (p != NO_NODE && IS (p, OPERATOR) && PRIO (INFO (p)) == u) {
       FORWARD (p);
       p = reduce_dyadic (p, u + 1);
     }
   }
   return p;
 }
 
 //! @brief Reduce tertiaries completely.
 
 void reduce_tertiaries (NODE_T * p)
 {
   NODE_T *q;
   BOOL_T siga;
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, TERTIARY, NIHIL, STOP);
     reduce (q, NO_NOTE, NO_TICK, FORMULA, MONADIC_FORMULA, STOP);
     reduce (q, NO_NOTE, NO_TICK, TERTIARY, FORMULA, STOP);
     reduce (q, NO_NOTE, NO_TICK, TERTIARY, SECONDARY, STOP);
   }
   siga = A68_TRUE;
   while (siga) {
     siga = A68_FALSE;
     for (q = p; q != NO_NODE; FORWARD (q)) {
       reduce (q, NO_NOTE, &siga, TRANSPOSE_FUNCTION, TRANSPOSE_SYMBOL, TERTIARY, STOP);
       reduce (q, NO_NOTE, &siga, DIAGONAL_FUNCTION, TERTIARY, DIAGONAL_SYMBOL, TERTIARY, STOP);
       reduce (q, NO_NOTE, &siga, DIAGONAL_FUNCTION, DIAGONAL_SYMBOL, TERTIARY, STOP);
       reduce (q, NO_NOTE, &siga, COLUMN_FUNCTION, TERTIARY, COLUMN_SYMBOL, TERTIARY, STOP);
       reduce (q, NO_NOTE, &siga, COLUMN_FUNCTION, COLUMN_SYMBOL, TERTIARY, STOP);
       reduce (q, NO_NOTE, &siga, ROW_FUNCTION, TERTIARY, ROW_SYMBOL, TERTIARY, STOP);
       reduce (q, NO_NOTE, &siga, ROW_FUNCTION, ROW_SYMBOL, TERTIARY, STOP);
     }
     for (q = p; q != NO_NODE; FORWARD (q)) {
       reduce (q, a68_extension, &siga, TERTIARY, TRANSPOSE_FUNCTION, STOP);
       reduce (q, a68_extension, &siga, TERTIARY, DIAGONAL_FUNCTION, STOP);
       reduce (q, a68_extension, &siga, TERTIARY, COLUMN_FUNCTION, STOP);
       reduce (q, a68_extension, &siga, TERTIARY, ROW_FUNCTION, STOP);
     }
   }
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, IDENTITY_RELATION, TERTIARY, IS_SYMBOL, TERTIARY, STOP);
     reduce (q, NO_NOTE, NO_TICK, IDENTITY_RELATION, TERTIARY, ISNT_SYMBOL, TERTIARY, STOP);
   }
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, AND_FUNCTION, TERTIARY, ANDF_SYMBOL, TERTIARY, STOP);
     reduce (q, NO_NOTE, NO_TICK, OR_FUNCTION, TERTIARY, ORF_SYMBOL, TERTIARY, STOP);
   }
 }
 
 //! @brief Reduce units.
 
 void reduce_units (NODE_T * p)
 {
   NODE_T *q;
 // Stray ~ is a SKIP.
   for (q = p; q != NO_NODE; FORWARD (q)) {
     if (IS (q, OPERATOR) && IS_LITERALLY (q, "~")) {
       ATTRIBUTE (q) = SKIP;
     }
   }
 // Reduce units.
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, UNIT, ASSIGNATION, STOP);
     reduce (q, NO_NOTE, NO_TICK, UNIT, IDENTITY_RELATION, STOP);
     reduce (q, a68_extension, NO_TICK, UNIT, AND_FUNCTION, STOP);
     reduce (q, a68_extension, NO_TICK, UNIT, OR_FUNCTION, STOP);
     reduce (q, NO_NOTE, NO_TICK, UNIT, ROUTINE_TEXT, STOP);
     reduce (q, NO_NOTE, NO_TICK, UNIT, JUMP, STOP);
     reduce (q, NO_NOTE, NO_TICK, UNIT, SKIP, STOP);
     reduce (q, NO_NOTE, NO_TICK, UNIT, TERTIARY, STOP);
     reduce (q, NO_NOTE, NO_TICK, UNIT, ASSERTION, STOP);
     reduce (q, NO_NOTE, NO_TICK, UNIT, CODE_CLAUSE, STOP);
   }
 }
 
 //! @brief Reduce_generic arguments.
 
 void reduce_generic_arguments (NODE_T * p)
 {
   NODE_T *q;
   BOOL_T siga;
   for (q = p; q != NO_NODE; FORWARD (q)) {
     if (IS (q, UNIT)) {
       reduce (q, NO_NOTE, NO_TICK, TRIMMER, UNIT, COLON_SYMBOL, UNIT, AT_SYMBOL, UNIT, STOP);
       reduce (q, NO_NOTE, NO_TICK, TRIMMER, UNIT, COLON_SYMBOL, UNIT, STOP);
       reduce (q, NO_NOTE, NO_TICK, TRIMMER, UNIT, COLON_SYMBOL, AT_SYMBOL, UNIT, STOP);
       reduce (q, NO_NOTE, NO_TICK, TRIMMER, UNIT, COLON_SYMBOL, STOP);
       reduce (q, NO_NOTE, NO_TICK, TRIMMER, UNIT, DOTDOT_SYMBOL, UNIT, AT_SYMBOL, UNIT, STOP);
       reduce (q, NO_NOTE, NO_TICK, TRIMMER, UNIT, DOTDOT_SYMBOL, UNIT, STOP);
       reduce (q, NO_NOTE, NO_TICK, TRIMMER, UNIT, DOTDOT_SYMBOL, AT_SYMBOL, UNIT, STOP);
       reduce (q, NO_NOTE, NO_TICK, TRIMMER, UNIT, DOTDOT_SYMBOL, STOP);
     } else if (IS (q, COLON_SYMBOL)) {
       reduce (q, NO_NOTE, NO_TICK, TRIMMER, COLON_SYMBOL, UNIT, AT_SYMBOL, UNIT, STOP);
       reduce (q, NO_NOTE, NO_TICK, TRIMMER, COLON_SYMBOL, UNIT, STOP);
       reduce (q, NO_NOTE, NO_TICK, TRIMMER, COLON_SYMBOL, AT_SYMBOL, UNIT, STOP);
       reduce (q, NO_NOTE, NO_TICK, TRIMMER, COLON_SYMBOL, STOP);
     } else if (IS (q, DOTDOT_SYMBOL)) {
       reduce (q, NO_NOTE, NO_TICK, TRIMMER, DOTDOT_SYMBOL, UNIT, AT_SYMBOL, UNIT, STOP);
       reduce (q, NO_NOTE, NO_TICK, TRIMMER, DOTDOT_SYMBOL, UNIT, STOP);
       reduce (q, NO_NOTE, NO_TICK, TRIMMER, DOTDOT_SYMBOL, AT_SYMBOL, UNIT, STOP);
       reduce (q, NO_NOTE, NO_TICK, TRIMMER, DOTDOT_SYMBOL, STOP);
     }
   }
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, TRIMMER, UNIT, AT_SYMBOL, UNIT, STOP);
   }
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, TRIMMER, AT_SYMBOL, UNIT, STOP);
   }
   for (q = p; q && NEXT (q); FORWARD (q)) {
     if (IS (q, COMMA_SYMBOL)) {
       if (!(ATTRIBUTE (NEXT (q)) == UNIT || ATTRIBUTE (NEXT (q)) == TRIMMER)) {
         pad_node (q, TRIMMER);
       }
     } else {
       if (IS (NEXT (q), COMMA_SYMBOL)) {
         if (!IS (q, UNIT) && !IS (q, TRIMMER)) {
           pad_node (q, TRIMMER);
         }
       }
     }
   }
   q = NEXT (p);
   ABEND (q == NO_NODE, ERROR_INTERNAL_CONSISTENCY, __func__);
   reduce (q, NO_NOTE, NO_TICK, GENERIC_ARGUMENT_LIST, UNIT, STOP);
   reduce (q, NO_NOTE, NO_TICK, GENERIC_ARGUMENT_LIST, TRIMMER, STOP);
   do {
     siga = A68_FALSE;
     reduce (q, NO_NOTE, &siga, GENERIC_ARGUMENT_LIST, GENERIC_ARGUMENT_LIST, COMMA_SYMBOL, UNIT, STOP);
     reduce (q, NO_NOTE, &siga, GENERIC_ARGUMENT_LIST, GENERIC_ARGUMENT_LIST, COMMA_SYMBOL, TRIMMER, STOP);
     reduce (q, strange_separator, &siga, GENERIC_ARGUMENT_LIST, GENERIC_ARGUMENT_LIST, UNIT, STOP);
     reduce (q, strange_separator, &siga, GENERIC_ARGUMENT_LIST, GENERIC_ARGUMENT_LIST, TRIMMER, STOP);
   } while (siga);
 }
 
 //! @brief Reduce bounds.
 
 void reduce_bounds (NODE_T * p)
 {
   NODE_T *q;
   BOOL_T siga;
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, BOUND, UNIT, COLON_SYMBOL, UNIT, STOP);
     reduce (q, NO_NOTE, NO_TICK, BOUND, UNIT, DOTDOT_SYMBOL, UNIT, STOP);
     reduce (q, NO_NOTE, NO_TICK, BOUND, UNIT, STOP);
   }
   q = NEXT (p);
   reduce (q, NO_NOTE, NO_TICK, BOUNDS_LIST, BOUND, STOP);
   reduce (q, NO_NOTE, NO_TICK, FORMAL_BOUNDS_LIST, COMMA_SYMBOL, STOP);
   reduce (q, NO_NOTE, NO_TICK, ALT_FORMAL_BOUNDS_LIST, COLON_SYMBOL, STOP);
   reduce (q, NO_NOTE, NO_TICK, ALT_FORMAL_BOUNDS_LIST, DOTDOT_SYMBOL, STOP);
   do {
     siga = A68_FALSE;
     reduce (q, NO_NOTE, &siga, BOUNDS_LIST, BOUNDS_LIST, COMMA_SYMBOL, BOUND, STOP);
     reduce (q, NO_NOTE, &siga, FORMAL_BOUNDS_LIST, FORMAL_BOUNDS_LIST, COMMA_SYMBOL, STOP);
     reduce (q, NO_NOTE, &siga, ALT_FORMAL_BOUNDS_LIST, FORMAL_BOUNDS_LIST, COLON_SYMBOL, STOP);
     reduce (q, NO_NOTE, &siga, ALT_FORMAL_BOUNDS_LIST, FORMAL_BOUNDS_LIST, DOTDOT_SYMBOL, STOP);
     reduce (q, NO_NOTE, &siga, FORMAL_BOUNDS_LIST, ALT_FORMAL_BOUNDS_LIST, COMMA_SYMBOL, STOP);
     reduce (q, strange_separator, &siga, BOUNDS_LIST, BOUNDS_LIST, BOUND, STOP);
   } while (siga);
 }
 
 //! @brief Reduce argument packs.
 
 void reduce_arguments (NODE_T * p)
 {
   if (NEXT (p) != NO_NODE) {
     NODE_T *q = NEXT (p);
     BOOL_T siga;
     reduce (q, NO_NOTE, NO_TICK, ARGUMENT_LIST, UNIT, STOP);
     do {
       siga = A68_FALSE;
       reduce (q, NO_NOTE, &siga, ARGUMENT_LIST, ARGUMENT_LIST, COMMA_SYMBOL, UNIT, STOP);
       reduce (q, strange_separator, &siga, ARGUMENT_LIST, ARGUMENT_LIST, UNIT, STOP);
     } while (siga);
   }
 }
 
 //! @brief Reduce declarations.
 
 void reduce_basic_declarations (NODE_T * p)
 {
   NODE_T *q;
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, ENVIRON_NAME, ENVIRON_SYMBOL, ROW_CHAR_DENOTATION, STOP);
     reduce (q, NO_NOTE, NO_TICK, PRIORITY_DECLARATION, PRIO_SYMBOL, DEFINING_OPERATOR, EQUALS_SYMBOL, PRIORITY, STOP);
     reduce (q, NO_NOTE, NO_TICK, MODE_DECLARATION, MODE_SYMBOL, DEFINING_INDICANT, EQUALS_SYMBOL, DECLARER, STOP);
     reduce (q, NO_NOTE, NO_TICK, MODE_DECLARATION, MODE_SYMBOL, DEFINING_INDICANT, EQUALS_SYMBOL, VOID_SYMBOL, STOP);
     reduce (q, NO_NOTE, NO_TICK, PROCEDURE_DECLARATION, PROC_SYMBOL, DEFINING_IDENTIFIER, EQUALS_SYMBOL, ROUTINE_TEXT, STOP);
     reduce (q, NO_NOTE, NO_TICK, PROCEDURE_VARIABLE_DECLARATION, PROC_SYMBOL, DEFINING_IDENTIFIER, ASSIGN_SYMBOL, ROUTINE_TEXT, STOP);
     reduce (q, NO_NOTE, NO_TICK, PROCEDURE_VARIABLE_DECLARATION, QUALIFIER, PROC_SYMBOL, DEFINING_IDENTIFIER, ASSIGN_SYMBOL, ROUTINE_TEXT, STOP);
     reduce (q, NO_NOTE, NO_TICK, BRIEF_OPERATOR_DECLARATION, OP_SYMBOL, DEFINING_OPERATOR, EQUALS_SYMBOL, ROUTINE_TEXT, STOP);
 // Errors.
     reduce (q, strange_tokens, NO_TICK, PRIORITY_DECLARATION, PRIO_SYMBOL, -DEFINING_OPERATOR, -EQUALS_SYMBOL, -PRIORITY, STOP);
     reduce (q, strange_tokens, NO_TICK, MODE_DECLARATION, MODE_SYMBOL, DEFINING_INDICANT, EQUALS_SYMBOL, -DECLARER, STOP);
     reduce (q, strange_tokens, NO_TICK, PROCEDURE_DECLARATION, PROC_SYMBOL, DEFINING_IDENTIFIER, EQUALS_SYMBOL, -ROUTINE_TEXT, STOP);
     reduce (q, strange_tokens, NO_TICK, PROCEDURE_VARIABLE_DECLARATION, PROC_SYMBOL, DEFINING_IDENTIFIER, ASSIGN_SYMBOL, -ROUTINE_TEXT, STOP);
     reduce (q, strange_tokens, NO_TICK, PROCEDURE_VARIABLE_DECLARATION, QUALIFIER, PROC_SYMBOL, DEFINING_IDENTIFIER, ASSIGN_SYMBOL, -ROUTINE_TEXT, STOP);
     reduce (q, strange_tokens, NO_TICK, BRIEF_OPERATOR_DECLARATION, OP_SYMBOL, DEFINING_OPERATOR, EQUALS_SYMBOL, -ROUTINE_TEXT, STOP);
 // Errors. WILDCARD catches TERTIARY which catches IDENTIFIER.
     reduce (q, strange_tokens, NO_TICK, PROCEDURE_DECLARATION, PROC_SYMBOL, WILDCARD, ROUTINE_TEXT, STOP);
   }
   for (q = p; q != NO_NODE; FORWARD (q)) {
     BOOL_T siga;
     do {
       siga = A68_FALSE;
       reduce (q, NO_NOTE, &siga, ENVIRON_NAME, ENVIRON_NAME, COMMA_SYMBOL, ROW_CHAR_DENOTATION, STOP);
       reduce (q, NO_NOTE, &siga, PRIORITY_DECLARATION, PRIORITY_DECLARATION, COMMA_SYMBOL, DEFINING_OPERATOR, EQUALS_SYMBOL, PRIORITY, STOP);
       reduce (q, NO_NOTE, &siga, MODE_DECLARATION, MODE_DECLARATION, COMMA_SYMBOL, DEFINING_INDICANT, EQUALS_SYMBOL, DECLARER, STOP);
       reduce (q, NO_NOTE, &siga, MODE_DECLARATION, MODE_DECLARATION, COMMA_SYMBOL, DEFINING_INDICANT, EQUALS_SYMBOL, VOID_SYMBOL, STOP);
       reduce (q, NO_NOTE, &siga, PROCEDURE_DECLARATION, PROCEDURE_DECLARATION, COMMA_SYMBOL, DEFINING_IDENTIFIER, EQUALS_SYMBOL, ROUTINE_TEXT, STOP);
       reduce (q, NO_NOTE, &siga, PROCEDURE_VARIABLE_DECLARATION, PROCEDURE_VARIABLE_DECLARATION, COMMA_SYMBOL, DEFINING_IDENTIFIER, ASSIGN_SYMBOL, ROUTINE_TEXT, STOP);
       reduce (q, NO_NOTE, &siga, BRIEF_OPERATOR_DECLARATION, BRIEF_OPERATOR_DECLARATION, COMMA_SYMBOL, DEFINING_OPERATOR, EQUALS_SYMBOL, ROUTINE_TEXT, STOP);
 // Errors. WILDCARD catches TERTIARY which catches IDENTIFIER.
       reduce (q, strange_tokens, &siga, PROCEDURE_DECLARATION, PROCEDURE_DECLARATION, COMMA_SYMBOL, WILDCARD, ROUTINE_TEXT, STOP);
     } while (siga);
   }
 }
 
 //! @brief Reduce declaration lists.
 
 void reduce_declaration_lists (NODE_T * p)
 {
   NODE_T *q;
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, IDENTITY_DECLARATION, DECLARER, DEFINING_IDENTIFIER, EQUALS_SYMBOL, UNIT, STOP);
     reduce (q, NO_NOTE, NO_TICK, VARIABLE_DECLARATION, QUALIFIER, DECLARER, DEFINING_IDENTIFIER, ASSIGN_SYMBOL, UNIT, STOP);
     reduce (q, NO_NOTE, NO_TICK, VARIABLE_DECLARATION, QUALIFIER, DECLARER, DEFINING_IDENTIFIER, STOP);
     reduce (q, NO_NOTE, NO_TICK, VARIABLE_DECLARATION, DECLARER, DEFINING_IDENTIFIER, ASSIGN_SYMBOL, UNIT, STOP);
     reduce (q, NO_NOTE, NO_TICK, VARIABLE_DECLARATION, DECLARER, DEFINING_IDENTIFIER, STOP);
   }
   for (q = p; q != NO_NODE; FORWARD (q)) {
     BOOL_T siga;
     do {
       siga = A68_FALSE;
       reduce (q, NO_NOTE, &siga, IDENTITY_DECLARATION, IDENTITY_DECLARATION, COMMA_SYMBOL, DEFINING_IDENTIFIER, EQUALS_SYMBOL, UNIT, STOP);
       reduce (q, NO_NOTE, &siga, VARIABLE_DECLARATION, VARIABLE_DECLARATION, COMMA_SYMBOL, DEFINING_IDENTIFIER, ASSIGN_SYMBOL, UNIT, STOP);
       if (!whether (q, VARIABLE_DECLARATION, COMMA_SYMBOL, DEFINING_IDENTIFIER, ASSIGN_SYMBOL, UNIT, STOP)) {
         reduce (q, NO_NOTE, &siga, VARIABLE_DECLARATION, VARIABLE_DECLARATION, COMMA_SYMBOL, DEFINING_IDENTIFIER, STOP);
       }
     } while (siga);
   }
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, OPERATOR_DECLARATION, OPERATOR_PLAN, DEFINING_OPERATOR, EQUALS_SYMBOL, UNIT, STOP);
   }
   for (q = p; q != NO_NODE; FORWARD (q)) {
     BOOL_T siga;
     do {
       siga = A68_FALSE;
       reduce (q, NO_NOTE, &siga, OPERATOR_DECLARATION, OPERATOR_DECLARATION, COMMA_SYMBOL, DEFINING_OPERATOR, EQUALS_SYMBOL, UNIT, STOP);
     } while (siga);
   }
   for (q = p; q != NO_NODE; FORWARD (q)) {
     reduce (q, NO_NOTE, NO_TICK, DECLARATION_LIST, MODE_DECLARATION, STOP);
     reduce (q, NO_NOTE, NO_TICK, DECLARATION_LIST, PRIORITY_DECLARATION, STOP);
     reduce (q, NO_NOTE, NO_TICK, DECLARATION_LIST, BRIEF_OPERATOR_DECLARATION, STOP);
     reduce (q, NO_NOTE, NO_TICK, DECLARATION_LIST, OPERATOR_DECLARATION, STOP);
     reduce (q, NO_NOTE, NO_TICK, DECLARATION_LIST, IDENTITY_DECLARATION, STOP);
     reduce (q, NO_NOTE, NO_TICK, DECLARATION_LIST, PROCEDURE_DECLARATION, STOP);
     reduce (q, NO_NOTE, NO_TICK, DECLARATION_LIST, PROCEDURE_VARIABLE_DECLARATION, STOP);
     reduce (q, NO_NOTE, NO_TICK, DECLARATION_LIST, VARIABLE_DECLARATION, STOP);
     reduce (q, NO_NOTE, NO_TICK, DECLARATION_LIST, ENVIRON_NAME, STOP);
   }
   for (q = p; q != NO_NODE; FORWARD (q)) {
     BOOL_T siga;
     do {
       siga = A68_FALSE;
       reduce (q, NO_NOTE, &siga, DECLARATION_LIST, DECLARATION_LIST, COMMA_SYMBOL, DECLARATION_LIST, STOP);
     } while (siga);
   }
 }
 
 //! @brief Reduce serial clauses.
 
 void reduce_serial_clauses (NODE_T * p)
 {
   if (NEXT (p) != NO_NODE) {
     NODE_T *q = NEXT (p), *u;
     BOOL_T siga, label_seen;
 // Check wrong exits.
     for (u = q; u != NO_NODE; FORWARD (u)) {
       if (IS (u, EXIT_SYMBOL)) {
         if (NEXT (u) == NO_NODE || !IS (NEXT (u), LABELED_UNIT)) {
           diagnostic (A68_SYNTAX_ERROR, u, ERROR_LABELED_UNIT_MUST_FOLLOW);
         }
       }
     }
 // Check wrong jumps and declarations.
     for (u = q, label_seen = A68_FALSE; u != NO_NODE; FORWARD (u)) {
       if (IS (u, LABELED_UNIT)) {
         label_seen = A68_TRUE;
       } else if (IS (u, DECLARATION_LIST)) {
         if (label_seen) {
           diagnostic (A68_SYNTAX_ERROR, u, ERROR_LABEL_BEFORE_DECLARATION);
         }
       }
     }
 // Reduce serial clauses.
     reduce (q, NO_NOTE, NO_TICK, SERIAL_CLAUSE, LABELED_UNIT, STOP);
     reduce (q, NO_NOTE, NO_TICK, SERIAL_CLAUSE, UNIT, STOP);
     reduce (q, NO_NOTE, NO_TICK, INITIALISER_SERIES, DECLARATION_LIST, STOP);
     do {
       siga = A68_FALSE;
       if (IS (q, SERIAL_CLAUSE)) {
         reduce (q, NO_NOTE, &siga, SERIAL_CLAUSE, SERIAL_CLAUSE, SEMI_SYMBOL, UNIT, STOP);
         reduce (q, NO_NOTE, &siga, SERIAL_CLAUSE, SERIAL_CLAUSE, EXIT_SYMBOL, LABELED_UNIT, STOP);
         reduce (q, NO_NOTE, &siga, SERIAL_CLAUSE, SERIAL_CLAUSE, SEMI_SYMBOL, LABELED_UNIT, STOP);
         reduce (q, NO_NOTE, &siga, INITIALISER_SERIES, SERIAL_CLAUSE, SEMI_SYMBOL, DECLARATION_LIST, STOP);
 // Errors 
         reduce (q, strange_separator, &siga, SERIAL_CLAUSE, SERIAL_CLAUSE, COMMA_SYMBOL, UNIT, STOP);
         reduce (q, strange_separator, &siga, SERIAL_CLAUSE, SERIAL_CLAUSE, COMMA_SYMBOL, LABELED_UNIT, STOP);
         reduce (q, strange_separator, &siga, INITIALISER_SERIES, SERIAL_CLAUSE, COMMA_SYMBOL, DECLARATION_LIST, STOP);
         reduce (q, strange_separator, &siga, SERIAL_CLAUSE, SERIAL_CLAUSE, COLON_SYMBOL, UNIT, STOP);
         reduce (q, strange_separator, &siga, SERIAL_CLAUSE, SERIAL_CLAUSE, COLON_SYMBOL, LABELED_UNIT, STOP);
         reduce (q, strange_separator, &siga, INITIALISER_SERIES, SERIAL_CLAUSE, COLON_SYMBOL, DECLARATION_LIST, STOP);
         reduce (q, strange_separator, &siga, SERIAL_CLAUSE, SERIAL_CLAUSE, UNIT, STOP);
         reduce (q, strange_separator, &siga, SERIAL_CLAUSE, SERIAL_CLAUSE, LABELED_UNIT, STOP);
         reduce (q, strange_separator, &siga, INITIALISER_SERIES, SERIAL_CLAUSE, DECLARATION_LIST, STOP);
       } else if (IS (q, INITIALISER_SERIES)) {
         reduce (q, NO_NOTE, &siga, SERIAL_CLAUSE, INITIALISER_SERIES, SEMI_SYMBOL, UNIT, STOP);
         reduce (q, NO_NOTE, &siga, SERIAL_CLAUSE, INITIALISER_SERIES, SEMI_SYMBOL, LABELED_UNIT, STOP);
         reduce (q, NO_NOTE, &siga, INITIALISER_SERIES, INITIALISER_SERIES, SEMI_SYMBOL, DECLARATION_LIST, STOP);
 // Errors 
         reduce (q, strange_separator, &siga, SERIAL_CLAUSE, INITIALISER_SERIES, COMMA_SYMBOL, UNIT, STOP);
         reduce (q, strange_separator, &siga, SERIAL_CLAUSE, INITIALISER_SERIES, COMMA_SYMBOL, LABELED_UNIT, STOP);
         reduce (q, strange_separator, &siga, INITIALISER_SERIES, INITIALISER_SERIES, COMMA_SYMBOL, DECLARATION_LIST, STOP);
         reduce (q, strange_separator, &siga, SERIAL_CLAUSE, INITIALISER_SERIES, COLON_SYMBOL, UNIT, STOP);
         reduce (q, strange_separator, &siga, SERIAL_CLAUSE, INITIALISER_SERIES, COLON_SYMBOL, LABELED_UNIT, STOP);
         reduce (q, strange_separator, &siga, INITIALISER_SERIES, INITIALISER_SERIES, COLON_SYMBOL, DECLARATION_LIST, STOP);
         reduce (q, strange_separator, &siga, SERIAL_CLAUSE, INITIALISER_SERIES, UNIT, STOP);
         reduce (q, strange_separator, &siga, SERIAL_CLAUSE, INITIALISER_SERIES, LABELED_UNIT, STOP);
         reduce (q, strange_separator, &siga, INITIALISER_SERIES, INITIALISER_SERIES, DECLARATION_LIST, STOP);
       }
     }
     while (siga);
   }
 }
 
 //! @brief Reduce enquiry clauses.
 
 void reduce_enquiry_clauses (NODE_T * p)
 {
   if (NEXT (p) != NO_NODE) {
     NODE_T *q = NEXT (p);
     BOOL_T siga;
     reduce (q, NO_NOTE, NO_TICK, ENQUIRY_CLAUSE, UNIT, STOP);
     reduce (q, NO_NOTE, NO_TICK, INITIALISER_SERIES, DECLARATION_LIST, STOP);
     do {
       siga = A68_FALSE;
       if (IS (q, ENQUIRY_CLAUSE)) {
         reduce (q, NO_NOTE, &siga, ENQUIRY_CLAUSE, ENQUIRY_CLAUSE, SEMI_SYMBOL, UNIT, STOP);
         reduce (q, NO_NOTE, &siga, INITIALISER_SERIES, ENQUIRY_CLAUSE, SEMI_SYMBOL, DECLARATION_LIST, STOP);
         reduce (q, strange_separator, &siga, ENQUIRY_CLAUSE, ENQUIRY_CLAUSE, COMMA_SYMBOL, UNIT, STOP);
         reduce (q, strange_separator, &siga, INITIALISER_SERIES, ENQUIRY_CLAUSE, COMMA_SYMBOL, DECLARATION_LIST, STOP);
         reduce (q, strange_separator, &siga, ENQUIRY_CLAUSE, ENQUIRY_CLAUSE, COLON_SYMBOL, UNIT, STOP);
         reduce (q, strange_separator, &siga, INITIALISER_SERIES, ENQUIRY_CLAUSE, COLON_SYMBOL, DECLARATION_LIST, STOP);
         reduce (q, strange_separator, &siga, ENQUIRY_CLAUSE, ENQUIRY_CLAUSE, UNIT, STOP);
         reduce (q, strange_separator, &siga, INITIALISER_SERIES, ENQUIRY_CLAUSE, DECLARATION_LIST, STOP);
       } else if (IS (q, INITIALISER_SERIES)) {
         reduce (q, NO_NOTE, &siga, ENQUIRY_CLAUSE, INITIALISER_SERIES, SEMI_SYMBOL, UNIT, STOP);
         reduce (q, NO_NOTE, &siga, INITIALISER_SERIES, INITIALISER_SERIES, SEMI_SYMBOL, DECLARATION_LIST, STOP);
         reduce (q, strange_separator, &siga, ENQUIRY_CLAUSE, INITIALISER_SERIES, COMMA_SYMBOL, UNIT, STOP);
         reduce (q, strange_separator, &siga, INITIALISER_SERIES, INITIALISER_SERIES, COMMA_SYMBOL, DECLARATION_LIST, STOP);
         reduce (q, strange_separator, &siga, ENQUIRY_CLAUSE, INITIALISER_SERIES, COLON_SYMBOL, UNIT, STOP);
         reduce (q, strange_separator, &siga, INITIALISER_SERIES, INITIALISER_SERIES, COLON_SYMBOL, DECLARATION_LIST, STOP);
         reduce (q, strange_separator, &siga, ENQUIRY_CLAUSE, INITIALISER_SERIES, UNIT, STOP);
         reduce (q, strange_separator, &siga, INITIALISER_SERIES, INITIALISER_SERIES, DECLARATION_LIST, STOP);
       }
     }
     while (siga);
   }
 }
 
 //! @brief Reduce collateral clauses.
 
 void reduce_collateral_clauses (NODE_T * p)
 {
   if (NEXT (p) != NO_NODE) {
     NODE_T *q = NEXT (p);
     if (IS (q, UNIT)) {
       BOOL_T siga;
       reduce (q, NO_NOTE, NO_TICK, UNIT_LIST, UNIT, STOP);
       do {
         siga = A68_FALSE;
         reduce (q, NO_NOTE, &siga, UNIT_LIST, UNIT_LIST, COMMA_SYMBOL, UNIT, STOP);
         reduce (q, strange_separator, &siga, UNIT_LIST, UNIT_LIST, UNIT, STOP);
       } while (siga);
     } else if (IS (q, SPECIFIED_UNIT)) {
       BOOL_T siga;
       reduce (q, NO_NOTE, NO_TICK, SPECIFIED_UNIT_LIST, SPECIFIED_UNIT, STOP);
       do {
         siga = A68_FALSE;
         reduce (q, NO_NOTE, &siga, SPECIFIED_UNIT_LIST, SPECIFIED_UNIT_LIST, COMMA_SYMBOL, SPECIFIED_UNIT, STOP);
         reduce (q, strange_separator, &siga, SPECIFIED_UNIT_LIST, SPECIFIED_UNIT_LIST, SPECIFIED_UNIT, STOP);
       } while (siga);
     }
   }
 }
 
 //! @brief Reduces enclosed clauses.
 
 void reduce_enclosed_clauses (NODE_T * q, int expect)
 {
   NODE_T *p = q;
   if (SUB (p) == NO_NODE) {
     if (IS (p, FOR_SYMBOL)) {
       reduce (p, NO_NOTE, NO_TICK, FOR_PART, FOR_SYMBOL, DEFINING_IDENTIFIER, STOP);
     } else if (IS (p, OPEN_SYMBOL)) {
       if (expect == ENQUIRY_CLAUSE) {
         reduce (p, NO_NOTE, NO_TICK, OPEN_PART, OPEN_SYMBOL, ENQUIRY_CLAUSE, STOP);
       } else if (expect == ARGUMENT) {
         reduce (p, NO_NOTE, NO_TICK, ARGUMENT, OPEN_SYMBOL, CLOSE_SYMBOL, STOP);
         reduce (p, NO_NOTE, NO_TICK, ARGUMENT, OPEN_SYMBOL, ARGUMENT_LIST, CLOSE_SYMBOL, STOP);
         reduce (p, empty_clause, NO_TICK, ARGUMENT, OPEN_SYMBOL, INITIALISER_SERIES, CLOSE_SYMBOL, STOP);
       } else if (expect == GENERIC_ARGUMENT) {
         if (whether (p, OPEN_SYMBOL, CLOSE_SYMBOL, STOP)) {
           pad_node (p, TRIMMER);
           reduce (p, NO_NOTE, NO_TICK, GENERIC_ARGUMENT, OPEN_SYMBOL, TRIMMER, CLOSE_SYMBOL, STOP);
         }
         reduce (p, NO_NOTE, NO_TICK, GENERIC_ARGUMENT, OPEN_SYMBOL, GENERIC_ARGUMENT_LIST, CLOSE_SYMBOL, STOP);
       } else if (expect == BOUNDS) {
         reduce (p, NO_NOTE, NO_TICK, FORMAL_BOUNDS, OPEN_SYMBOL, CLOSE_SYMBOL, STOP);
         reduce (p, NO_NOTE, NO_TICK, BOUNDS, OPEN_SYMBOL, BOUNDS_LIST, CLOSE_SYMBOL, STOP);
         reduce (p, NO_NOTE, NO_TICK, FORMAL_BOUNDS, OPEN_SYMBOL, FORMAL_BOUNDS_LIST, CLOSE_SYMBOL, STOP);
         reduce (p, NO_NOTE, NO_TICK, FORMAL_BOUNDS, OPEN_SYMBOL, ALT_FORMAL_BOUNDS_LIST, CLOSE_SYMBOL, STOP);
       } else {
         reduce (p, NO_NOTE, NO_TICK, CLOSED_CLAUSE, OPEN_SYMBOL, SERIAL_CLAUSE, CLOSE_SYMBOL, STOP);
         reduce (p, NO_NOTE, NO_TICK, COLLATERAL_CLAUSE, OPEN_SYMBOL, UNIT_LIST, CLOSE_SYMBOL, STOP);
         reduce (p, NO_NOTE, NO_TICK, COLLATERAL_CLAUSE, OPEN_SYMBOL, CLOSE_SYMBOL, STOP);
         reduce (p, empty_clause, NO_TICK, CLOSED_CLAUSE, OPEN_SYMBOL, INITIALISER_SERIES, CLOSE_SYMBOL, STOP);
       }
     } else if (IS (p, SUB_SYMBOL)) {
       if (expect == GENERIC_ARGUMENT) {
         if (whether (p, SUB_SYMBOL, BUS_SYMBOL, STOP)) {
           pad_node (p, TRIMMER);
           reduce (p, NO_NOTE, NO_TICK, GENERIC_ARGUMENT, SUB_SYMBOL, TRIMMER, BUS_SYMBOL, STOP);
         }
         reduce (p, NO_NOTE, NO_TICK, GENERIC_ARGUMENT, SUB_SYMBOL, GENERIC_ARGUMENT_LIST, BUS_SYMBOL, STOP);
       } else if (expect == BOUNDS) {
         reduce (p, NO_NOTE, NO_TICK, FORMAL_BOUNDS, SUB_SYMBOL, BUS_SYMBOL, STOP);
         reduce (p, NO_NOTE, NO_TICK, BOUNDS, SUB_SYMBOL, BOUNDS_LIST, BUS_SYMBOL, STOP);
         reduce (p, NO_NOTE, NO_TICK, FORMAL_BOUNDS, SUB_SYMBOL, FORMAL_BOUNDS_LIST, BUS_SYMBOL, STOP);
         reduce (p, NO_NOTE, NO_TICK, FORMAL_BOUNDS, SUB_SYMBOL, ALT_FORMAL_BOUNDS_LIST, BUS_SYMBOL, STOP);
       }
     } else if (IS (p, BEGIN_SYMBOL)) {
       reduce (p, NO_NOTE, NO_TICK, COLLATERAL_CLAUSE, BEGIN_SYMBOL, UNIT_LIST, END_SYMBOL, STOP);
       reduce (p, NO_NOTE, NO_TICK, COLLATERAL_CLAUSE, BEGIN_SYMBOL, END_SYMBOL, STOP);
       reduce (p, NO_NOTE, NO_TICK, CLOSED_CLAUSE, BEGIN_SYMBOL, SERIAL_CLAUSE, END_SYMBOL, STOP);
       reduce (p, empty_clause, NO_TICK, CLOSED_CLAUSE, BEGIN_SYMBOL, INITIALISER_SERIES, END_SYMBOL, STOP);
     } else if (IS (p, FORMAT_DELIMITER_SYMBOL)) {
       reduce (p, NO_NOTE, NO_TICK, FORMAT_TEXT, FORMAT_DELIMITER_SYMBOL, PICTURE_LIST, FORMAT_DELIMITER_SYMBOL, STOP);
       reduce (p, NO_NOTE, NO_TICK, FORMAT_TEXT, FORMAT_DELIMITER_SYMBOL, FORMAT_DELIMITER_SYMBOL, STOP);
     } else if (IS (p, FORMAT_OPEN_SYMBOL)) {
       reduce (p, NO_NOTE, NO_TICK, COLLECTION, FORMAT_OPEN_SYMBOL, PICTURE_LIST, FORMAT_CLOSE_SYMBOL, STOP);
     } else if (IS (p, IF_SYMBOL)) {
       reduce (p, NO_NOTE, NO_TICK, IF_PART, IF_SYMBOL, ENQUIRY_CLAUSE, STOP);
       reduce (p, empty_clause, NO_TICK, IF_PART, IF_SYMBOL, INITIALISER_SERIES, STOP);
     } else if (IS (p, THEN_SYMBOL)) {
       reduce (p, NO_NOTE, NO_TICK, THEN_PART, THEN_SYMBOL, SERIAL_CLAUSE, STOP);
       reduce (p, empty_clause, NO_TICK, THEN_PART, THEN_SYMBOL, INITIALISER_SERIES, STOP);
     } else if (IS (p, ELSE_SYMBOL)) {
       reduce (p, NO_NOTE, NO_TICK, ELSE_PART, ELSE_SYMBOL, SERIAL_CLAUSE, STOP);
       reduce (p, empty_clause, NO_TICK, ELSE_PART, ELSE_SYMBOL, INITIALISER_SERIES, STOP);
     } else if (IS (p, ELIF_SYMBOL)) {
       reduce (p, NO_NOTE, NO_TICK, ELIF_IF_PART, ELIF_SYMBOL, ENQUIRY_CLAUSE, STOP);
     } else if (IS (p, CASE_SYMBOL)) {
       reduce (p, NO_NOTE, NO_TICK, CASE_PART, CASE_SYMBOL, ENQUIRY_CLAUSE, STOP);
       reduce (p, empty_clause, NO_TICK, CASE_PART, CASE_SYMBOL, INITIALISER_SERIES, STOP);
     } else if (IS (p, IN_SYMBOL)) {
       reduce (p, NO_NOTE, NO_TICK, CASE_IN_PART, IN_SYMBOL, UNIT_LIST, STOP);
       reduce (p, NO_NOTE, NO_TICK, CONFORMITY_IN_PART, IN_SYMBOL, SPECIFIED_UNIT_LIST, STOP);
     } else if (IS (p, OUT_SYMBOL)) {
       reduce (p, NO_NOTE, NO_TICK, OUT_PART, OUT_SYMBOL, SERIAL_CLAUSE, STOP);
       reduce (p, empty_clause, NO_TICK, OUT_PART, OUT_SYMBOL, INITIALISER_SERIES, STOP);
     } else if (IS (p, OUSE_SYMBOL)) {
       reduce (p, NO_NOTE, NO_TICK, OUSE_PART, OUSE_SYMBOL, ENQUIRY_CLAUSE, STOP);
     } else if (IS (p, THEN_BAR_SYMBOL)) {
       reduce (p, NO_NOTE, NO_TICK, CHOICE, THEN_BAR_SYMBOL, SERIAL_CLAUSE, STOP);
       reduce (p, NO_NOTE, NO_TICK, CASE_CHOICE_CLAUSE, THEN_BAR_SYMBOL, UNIT_LIST, STOP);
       reduce (p, NO_NOTE, NO_TICK, CONFORMITY_CHOICE, THEN_BAR_SYMBOL, SPECIFIED_UNIT_LIST, STOP);
       reduce (p, NO_NOTE, NO_TICK, CONFORMITY_CHOICE, THEN_BAR_SYMBOL, SPECIFIED_UNIT, STOP);
       reduce (p, empty_clause, NO_TICK, CHOICE, THEN_BAR_SYMBOL, INITIALISER_SERIES, STOP);
     } else if (IS (p, ELSE_BAR_SYMBOL)) {
       reduce (p, NO_NOTE, NO_TICK, ELSE_OPEN_PART, ELSE_BAR_SYMBOL, ENQUIRY_CLAUSE, STOP);
       reduce (p, empty_clause, NO_TICK, ELSE_OPEN_PART, ELSE_BAR_SYMBOL, INITIALISER_SERIES, STOP);
     } else if (IS (p, FROM_SYMBOL)) {
       reduce (p, NO_NOTE, NO_TICK, FROM_PART, FROM_SYMBOL, UNIT, STOP);
     } else if (IS (p, BY_SYMBOL)) {
       reduce (p, NO_NOTE, NO_TICK, BY_PART, BY_SYMBOL, UNIT, STOP);
     } else if (IS (p, TO_SYMBOL)) {
       reduce (p, NO_NOTE, NO_TICK, TO_PART, TO_SYMBOL, UNIT, STOP);
     } else if (IS (p, DOWNTO_SYMBOL)) {
       reduce (p, NO_NOTE, NO_TICK, TO_PART, DOWNTO_SYMBOL, UNIT, STOP);
     } else if (IS (p, WHILE_SYMBOL)) {
       reduce (p, NO_NOTE, NO_TICK, WHILE_PART, WHILE_SYMBOL, ENQUIRY_CLAUSE, STOP);
       reduce (p, empty_clause, NO_TICK, WHILE_PART, WHILE_SYMBOL, INITIALISER_SERIES, STOP);
     } else if (IS (p, UNTIL_SYMBOL)) {
       reduce (p, NO_NOTE, NO_TICK, UNTIL_PART, UNTIL_SYMBOL, ENQUIRY_CLAUSE, STOP);
       reduce (p, empty_clause, NO_TICK, UNTIL_PART, UNTIL_SYMBOL, INITIALISER_SERIES, STOP);
     } else if (IS (p, DO_SYMBOL)) {
       reduce (p, NO_NOTE, NO_TICK, DO_PART, DO_SYMBOL, SERIAL_CLAUSE, UNTIL_PART, OD_SYMBOL, STOP);
       reduce (p, NO_NOTE, NO_TICK, DO_PART, DO_SYMBOL, SERIAL_CLAUSE, OD_SYMBOL, STOP);
       reduce (p, NO_NOTE, NO_TICK, DO_PART, DO_SYMBOL, UNTIL_PART, OD_SYMBOL, STOP);
     } else if (IS (p, ALT_DO_SYMBOL)) {
       reduce (p, NO_NOTE, NO_TICK, ALT_DO_PART, ALT_DO_SYMBOL, SERIAL_CLAUSE, UNTIL_PART, OD_SYMBOL, STOP);
       reduce (p, NO_NOTE, NO_TICK, ALT_DO_PART, ALT_DO_SYMBOL, SERIAL_CLAUSE, OD_SYMBOL, STOP);
       reduce (p, NO_NOTE, NO_TICK, ALT_DO_PART, ALT_DO_SYMBOL, UNTIL_PART, OD_SYMBOL, STOP);
     }
   }
   p = q;
   if (SUB (p) != NO_NODE) {
     if (IS (p, OPEN_PART)) {
       reduce (p, NO_NOTE, NO_TICK, CONDITIONAL_CLAUSE, OPEN_PART, CHOICE, CHOICE, CLOSE_SYMBOL, STOP);
       reduce (p, NO_NOTE, NO_TICK, CONDITIONAL_CLAUSE, OPEN_PART, CHOICE, CLOSE_SYMBOL, STOP);
       reduce (p, NO_NOTE, NO_TICK, CONDITIONAL_CLAUSE, OPEN_PART, CHOICE, BRIEF_ELIF_PART, STOP);
       reduce (p, NO_NOTE, NO_TICK, CASE_CLAUSE, OPEN_PART, CASE_CHOICE_CLAUSE, CHOICE, CLOSE_SYMBOL, STOP);
       reduce (p, NO_NOTE, NO_TICK, CASE_CLAUSE, OPEN_PART, CASE_CHOICE_CLAUSE, CLOSE_SYMBOL, STOP);
       reduce (p, NO_NOTE, NO_TICK, CASE_CLAUSE, OPEN_PART, CASE_CHOICE_CLAUSE, BRIEF_OUSE_PART, STOP);
       reduce (p, NO_NOTE, NO_TICK, CONFORMITY_CLAUSE, OPEN_PART, CONFORMITY_CHOICE, CHOICE, CLOSE_SYMBOL, STOP);
       reduce (p, NO_NOTE, NO_TICK, CONFORMITY_CLAUSE, OPEN_PART, CONFORMITY_CHOICE, CLOSE_SYMBOL, STOP);
       reduce (p, NO_NOTE, NO_TICK, CONFORMITY_CLAUSE, OPEN_PART, CONFORMITY_CHOICE, BRIEF_CONFORMITY_OUSE_PART, STOP);
     } else if (IS (p, ELSE_OPEN_PART)) {
       reduce (p, NO_NOTE, NO_TICK, BRIEF_ELIF_PART, ELSE_OPEN_PART, CHOICE, CHOICE, CLOSE_SYMBOL, STOP);
       reduce (p, NO_NOTE, NO_TICK, BRIEF_ELIF_PART, ELSE_OPEN_PART, CHOICE, CLOSE_SYMBOL, STOP);
       reduce (p, NO_NOTE, NO_TICK, BRIEF_ELIF_PART, ELSE_OPEN_PART, CHOICE, BRIEF_ELIF_PART, STOP);
       reduce (p, NO_NOTE, NO_TICK, BRIEF_OUSE_PART, ELSE_OPEN_PART, CASE_CHOICE_CLAUSE, CHOICE, CLOSE_SYMBOL, STOP);
       reduce (p, NO_NOTE, NO_TICK, BRIEF_OUSE_PART, ELSE_OPEN_PART, CASE_CHOICE_CLAUSE, CLOSE_SYMBOL, STOP);
       reduce (p, NO_NOTE, NO_TICK, BRIEF_OUSE_PART, ELSE_OPEN_PART, CASE_CHOICE_CLAUSE, BRIEF_OUSE_PART, STOP);
       reduce (p, NO_NOTE, NO_TICK, BRIEF_CONFORMITY_OUSE_PART, ELSE_OPEN_PART, CONFORMITY_CHOICE, CHOICE, CLOSE_SYMBOL, STOP);
       reduce (p, NO_NOTE, NO_TICK, BRIEF_CONFORMITY_OUSE_PART, ELSE_OPEN_PART, CONFORMITY_CHOICE, CLOSE_SYMBOL, STOP);
       reduce (p, NO_NOTE, NO_TICK, BRIEF_CONFORMITY_OUSE_PART, ELSE_OPEN_PART, CONFORMITY_CHOICE, BRIEF_CONFORMITY_OUSE_PART, STOP);
     } else if (IS (p, IF_PART)) {
       reduce (p, NO_NOTE, NO_TICK, CONDITIONAL_CLAUSE, IF_PART, THEN_PART, ELSE_PART, FI_SYMBOL, STOP);
       reduce (p, NO_NOTE, NO_TICK, CONDITIONAL_CLAUSE, IF_PART, THEN_PART, ELIF_PART, STOP);
       reduce (p, NO_NOTE, NO_TICK, CONDITIONAL_CLAUSE, IF_PART, THEN_PART, FI_SYMBOL, STOP);
     } else if (IS (p, ELIF_IF_PART)) {
       reduce (p, NO_NOTE, NO_TICK, ELIF_PART, ELIF_IF_PART, THEN_PART, ELSE_PART, FI_SYMBOL, STOP);
       reduce (p, NO_NOTE, NO_TICK, ELIF_PART, ELIF_IF_PART, THEN_PART, FI_SYMBOL, STOP);
       reduce (p, NO_NOTE, NO_TICK, ELIF_PART, ELIF_IF_PART, THEN_PART, ELIF_PART, STOP);
     } else if (IS (p, CASE_PART)) {
       reduce (p, NO_NOTE, NO_TICK, CASE_CLAUSE, CASE_PART, CASE_IN_PART, OUT_PART, ESAC_SYMBOL, STOP);
       reduce (p, NO_NOTE, NO_TICK, CASE_CLAUSE, CASE_PART, CASE_IN_PART, ESAC_SYMBOL, STOP);
       reduce (p, NO_NOTE, NO_TICK, CASE_CLAUSE, CASE_PART, CASE_IN_PART, CASE_OUSE_PART, STOP);
       reduce (p, NO_NOTE, NO_TICK, CONFORMITY_CLAUSE, CASE_PART, CONFORMITY_IN_PART, OUT_PART, ESAC_SYMBOL, STOP);
       reduce (p, NO_NOTE, NO_TICK, CONFORMITY_CLAUSE, CASE_PART, CONFORMITY_IN_PART, ESAC_SYMBOL, STOP);
       reduce (p, NO_NOTE, NO_TICK, CONFORMITY_CLAUSE, CASE_PART, CONFORMITY_IN_PART, CONFORMITY_OUSE_PART, STOP);
     } else if (IS (p, OUSE_PART)) {
       reduce (p, NO_NOTE, NO_TICK, CASE_OUSE_PART, OUSE_PART, CASE_IN_PART, OUT_PART, ESAC_SYMBOL, STOP);
       reduce (p, NO_NOTE, NO_TICK, CASE_OUSE_PART, OUSE_PART, CASE_IN_PART, ESAC_SYMBOL, STOP);
       reduce (p, NO_NOTE, NO_TICK, CASE_OUSE_PART, OUSE_PART, CASE_IN_PART, CASE_OUSE_PART, STOP);
       reduce (p, NO_NOTE, NO_TICK, CONFORMITY_OUSE_PART, OUSE_PART, CONFORMITY_IN_PART, OUT_PART, ESAC_SYMBOL, STOP);
       reduce (p, NO_NOTE, NO_TICK, CONFORMITY_OUSE_PART, OUSE_PART, CONFORMITY_IN_PART, ESAC_SYMBOL, STOP);
       reduce (p, NO_NOTE, NO_TICK, CONFORMITY_OUSE_PART, OUSE_PART, CONFORMITY_IN_PART, CONFORMITY_OUSE_PART, STOP);
     } else if (IS (p, FOR_PART)) {
       reduce (p, NO_NOTE, NO_TICK, LOOP_CLAUSE, FOR_PART, FROM_PART, BY_PART, TO_PART, WHILE_PART, ALT_DO_PART, STOP);
       reduce (p, NO_NOTE, NO_TICK, LOOP_CLAUSE, FOR_PART, FROM_PART, BY_PART, WHILE_PART, ALT_DO_PART, STOP);
       reduce (p, NO_NOTE, NO_TICK, LOOP_CLAUSE, FOR_PART, FROM_PART, TO_PART, WHILE_PART, ALT_DO_PART, STOP);
       reduce (p, NO_NOTE, NO_TICK, LOOP_CLAUSE, FOR_PART, FROM_PART, WHILE_PART, ALT_DO_PART, STOP);
       reduce (p, NO_NOTE, NO_TICK, LOOP_CLAUSE, FOR_PART, BY_PART, TO_PART, WHILE_PART, ALT_DO_PART, STOP);
       reduce (p, NO_NOTE, NO_TICK, LOOP_CLAUSE, FOR_PART, BY_PART, WHILE_PART, ALT_DO_PART, STOP);
       reduce (p, NO_NOTE, NO_TICK, LOOP_CLAUSE, FOR_PART, TO_PART, WHILE_PART, ALT_DO_PART, STOP);
       reduce (p, NO_NOTE, NO_TICK, LOOP_CLAUSE, FOR_PART, WHILE_PART, ALT_DO_PART, STOP);
       reduce (p, NO_NOTE, NO_TICK, LOOP_CLAUSE, FOR_PART, FROM_PART, BY_PART, TO_PART, ALT_DO_PART, STOP);
       reduce (p, NO_NOTE, NO_TICK, LOOP_CLAUSE, FOR_PART, FROM_PART, BY_PART, ALT_DO_PART, STOP);
       reduce (p, NO_NOTE, NO_TICK, LOOP_CLAUSE, FOR_PART, FROM_PART, TO_PART, ALT_DO_PART, STOP);
       reduce (p, NO_NOTE, NO_TICK, LOOP_CLAUSE, FOR_PART, FROM_PART, ALT_DO_PART, STOP);
       reduce (p, NO_NOTE, NO_TICK, LOOP_CLAUSE, FOR_PART, BY_PART, TO_PART, ALT_DO_PART, STOP);
       reduce (p, NO_NOTE, NO_TICK, LOOP_CLAUSE, FOR_PART, BY_PART, ALT_DO_PART, STOP);
       reduce (p, NO_NOTE, NO_TICK, LOOP_CLAUSE, FOR_PART, TO_PART, ALT_DO_PART, STOP);
       reduce (p, NO_NOTE, NO_TICK, LOOP_CLAUSE, FOR_PART, ALT_DO_PART, STOP);
     } else if (IS (p, FROM_PART)) {
       reduce (p, NO_NOTE, NO_TICK, LOOP_CLAUSE, FROM_PART, BY_PART, TO_PART, WHILE_PART, ALT_DO_PART, STOP);
       reduce (p, NO_NOTE, NO_TICK, LOOP_CLAUSE, FROM_PART, BY_PART, WHILE_PART, ALT_DO_PART, STOP);
       reduce (p, NO_NOTE, NO_TICK, LOOP_CLAUSE, FROM_PART, TO_PART, WHILE_PART, ALT_DO_PART, STOP);
       reduce (p, NO_NOTE, NO_TICK, LOOP_CLAUSE, FROM_PART, WHILE_PART, ALT_DO_PART, STOP);
       reduce (p, NO_NOTE, NO_TICK, LOOP_CLAUSE, FROM_PART, BY_PART, TO_PART, ALT_DO_PART, STOP);
       reduce (p, NO_NOTE, NO_TICK, LOOP_CLAUSE, FROM_PART, BY_PART, ALT_DO_PART, STOP);
       reduce (p, NO_NOTE, NO_TICK, LOOP_CLAUSE, FROM_PART, TO_PART, ALT_DO_PART, STOP);
       reduce (p, NO_NOTE, NO_TICK, LOOP_CLAUSE, FROM_PART, ALT_DO_PART, STOP);
     } else if (IS (p, BY_PART)) {
       reduce (p, NO_NOTE, NO_TICK, LOOP_CLAUSE, BY_PART, TO_PART, WHILE_PART, ALT_DO_PART, STOP);
       reduce (p, NO_NOTE, NO_TICK, LOOP_CLAUSE, BY_PART, WHILE_PART, ALT_DO_PART, STOP);
       reduce (p, NO_NOTE, NO_TICK, LOOP_CLAUSE, BY_PART, TO_PART, ALT_DO_PART, STOP);
       reduce (p, NO_NOTE, NO_TICK, LOOP_CLAUSE, BY_PART, ALT_DO_PART, STOP);
     } else if (IS (p, TO_PART)) {
       reduce (p, NO_NOTE, NO_TICK, LOOP_CLAUSE, TO_PART, WHILE_PART, ALT_DO_PART, STOP);
       reduce (p, NO_NOTE, NO_TICK, LOOP_CLAUSE, TO_PART, ALT_DO_PART, STOP);
     } else if (IS (p, WHILE_PART)) {
       reduce (p, NO_NOTE, NO_TICK, LOOP_CLAUSE, WHILE_PART, ALT_DO_PART, STOP);
     } else if (IS (p, DO_PART)) {
       reduce (p, NO_NOTE, NO_TICK, LOOP_CLAUSE, DO_PART, STOP);
     }
   }
 }
 
 //! @brief Substitute reduction when a phrase could not be parsed.
 
 void recover_from_error (NODE_T * p, int expect, BOOL_T suppress)
 {
 // This routine does not do fancy things as that might introduce more errors.
   NODE_T *q = p;
   if (p == NO_NODE) {
     return;
   }
   if (expect == SOME_CLAUSE) {
     expect = serial_or_collateral (p);
   }
   if (!suppress) {
 // Give an error message.
     NODE_T *w = p;
     char *seq = phrase_to_text (p, &w);
     if (strlen (seq) == 0) {
       if (ERROR_COUNT (&A68_JOB) == 0) {
         diagnostic (A68_SYNTAX_ERROR, w, ERROR_SYNTAX_EXPECTED, expect);
       }
     } else {
       diagnostic (A68_SYNTAX_ERROR, w, ERROR_INVALID_SEQUENCE, seq, expect);
     }
     if (ERROR_COUNT (&A68_JOB) >= MAX_ERRORS) {
       longjmp (A68_PARSER (bottom_up_crash_exit), 1);
     }
   }
 // Try to prevent spurious diagnostics by guessing what was expected.
   while (NEXT (q) != NO_NODE) {
     FORWARD (q);
   }
   if (is_one_of (p, BEGIN_SYMBOL, OPEN_SYMBOL, STOP)) {
     if (expect == ARGUMENT || expect == COLLATERAL_CLAUSE || expect == PARAMETER_PACK || expect == STRUCTURE_PACK || expect == UNION_PACK) {
       make_sub (p, q, expect);
     } else if (expect == ENQUIRY_CLAUSE) {
       make_sub (p, q, OPEN_PART);
     } else if (expect == FORMAL_DECLARERS) {
       make_sub (p, q, FORMAL_DECLARERS);
     } else {
       make_sub (p, q, CLOSED_CLAUSE);
     }
   } else if (IS (p, FORMAT_DELIMITER_SYMBOL) && expect == FORMAT_TEXT) {
     make_sub (p, q, FORMAT_TEXT);
   } else if (IS (p, CODE_SYMBOL)) {
     make_sub (p, q, CODE_CLAUSE);
   } else if (is_one_of (p, THEN_BAR_SYMBOL, CHOICE, STOP)) {
     make_sub (p, q, CHOICE);
   } else if (is_one_of (p, IF_SYMBOL, IF_PART, STOP)) {
     make_sub (p, q, IF_PART);
   } else if (is_one_of (p, THEN_SYMBOL, THEN_PART, STOP)) {
     make_sub (p, q, THEN_PART);
   } else if (is_one_of (p, ELSE_SYMBOL, ELSE_PART, STOP)) {
     make_sub (p, q, ELSE_PART);
   } else if (is_one_of (p, ELIF_SYMBOL, ELIF_IF_PART, STOP)) {
     make_sub (p, q, ELIF_IF_PART);
   } else if (is_one_of (p, CASE_SYMBOL, CASE_PART, STOP)) {
     make_sub (p, q, CASE_PART);
   } else if (is_one_of (p, OUT_SYMBOL, OUT_PART, STOP)) {
     make_sub (p, q, OUT_PART);
   } else if (is_one_of (p, OUSE_SYMBOL, OUSE_PART, STOP)) {
     make_sub (p, q, OUSE_PART);
   } else if (is_one_of (p, FOR_SYMBOL, FOR_PART, STOP)) {
     make_sub (p, q, FOR_PART);
   } else if (is_one_of (p, FROM_SYMBOL, FROM_PART, STOP)) {
     make_sub (p, q, FROM_PART);
   } else if (is_one_of (p, BY_SYMBOL, BY_PART, STOP)) {
     make_sub (p, q, BY_PART);
   } else if (is_one_of (p, TO_SYMBOL, DOWNTO_SYMBOL, TO_PART, STOP)) {
     make_sub (p, q, TO_PART);
   } else if (is_one_of (p, WHILE_SYMBOL, WHILE_PART, STOP)) {
     make_sub (p, q, WHILE_PART);
   } else if (is_one_of (p, UNTIL_SYMBOL, UNTIL_PART, STOP)) {
     make_sub (p, q, UNTIL_PART);
   } else if (is_one_of (p, DO_SYMBOL, DO_PART, STOP)) {
     make_sub (p, q, DO_PART);
   } else if (is_one_of (p, ALT_DO_SYMBOL, ALT_DO_PART, STOP)) {
     make_sub (p, q, ALT_DO_PART);
   } else if (non_terminal_string (A68 (edit_line), expect) != NO_TEXT) {
     make_sub (p, q, expect);
   }
 }
 
 //! @brief Heuristic aid in pinpointing errors.
 
 void reduce_erroneous_units (NODE_T * p)
 {
 // Constructs are reduced to units in an attempt to limit spurious diagnostics.
   NODE_T *q;
   for (q = p; q != NO_NODE; FORWARD (q)) {
 // Some implementations allow selection from a tertiary, when there is no risk
 // of ambiguity. Algol68G follows RR, so some extra attention here to guide an
 // unsuspecting user.
     if (whether (q, SELECTOR, -SECONDARY, STOP)) {
       diagnostic (A68_SYNTAX_ERROR, NEXT (q), ERROR_SYNTAX_EXPECTED, SECONDARY);
       reduce (q, NO_NOTE, NO_TICK, UNIT, SELECTOR, WILDCARD, STOP);
     }
 // Attention for identity relations that require tertiaries.
     if (whether (q, -TERTIARY, IS_SYMBOL, TERTIARY, STOP) || whether (q, TERTIARY, IS_SYMBOL, -TERTIARY, STOP) || whether (q, -TERTIARY, IS_SYMBOL, -TERTIARY, STOP)) {
       diagnostic (A68_SYNTAX_ERROR, NEXT (q), ERROR_SYNTAX_EXPECTED, TERTIARY);
       reduce (q, NO_NOTE, NO_TICK, UNIT, WILDCARD, IS_SYMBOL, WILDCARD, STOP);
     } else if (whether (q, -TERTIARY, ISNT_SYMBOL, TERTIARY, STOP) || whether (q, TERTIARY, ISNT_SYMBOL, -TERTIARY, STOP) || whether (q, -TERTIARY, ISNT_SYMBOL, -TERTIARY, STOP)) {
       diagnostic (A68_SYNTAX_ERROR, NEXT (q), ERROR_SYNTAX_EXPECTED, TERTIARY);
       reduce (q, NO_NOTE, NO_TICK, UNIT, WILDCARD, ISNT_SYMBOL, WILDCARD, STOP);
     }
   }
 }
 
 // A posteriori checks of the syntax tree built by the BU parser.
 
 //! @brief Driver for a posteriori error checking.
 
 void bottom_up_error_check (NODE_T * p)
 {
   for (; p != NO_NODE; FORWARD (p)) {
     if (IS (p, BOOLEAN_PATTERN)) {
       int k = 0;
       count_pictures (SUB (p), &k);
       if (!(k == 0 || k == 2)) {
         diagnostic (A68_SYNTAX_ERROR, p, ERROR_FORMAT_PICTURE_NUMBER, ATTRIBUTE (p));
       }
     } else {
       bottom_up_error_check (SUB (p));
     }
   }
 }
 
 // Next part rearranges and checks the tree after the symbol tables are finished.
 
 //! @brief Transfer IDENTIFIER to JUMP where appropriate.
 
 void rearrange_goto_less_jumps (NODE_T * p)
 {
   for (; p != NO_NODE; FORWARD (p)) {
     if (IS (p, UNIT)) {
       NODE_T *q = SUB (p);
       if (IS (q, TERTIARY)) {
         NODE_T *tertiary = q;
         q = SUB (q);
         if (q != NO_NODE && IS (q, SECONDARY)) {
           q = SUB (q);
           if (q != NO_NODE && IS (q, PRIMARY)) {
             q = SUB (q);
             if (q != NO_NODE && IS (q, IDENTIFIER)) {
               if (is_identifier_or_label_global (TABLE (q), NSYMBOL (q)) == LABEL) {
                 ATTRIBUTE (tertiary) = JUMP;
                 SUB (tertiary) = q;
               }
             }
           }
         }
       }
     } else if (IS (p, TERTIARY)) {
       NODE_T *q = SUB (p);
       if (q != NO_NODE && IS (q, SECONDARY)) {
         NODE_T *secondary = q;
         q = SUB (q);
         if (q != NO_NODE && IS (q, PRIMARY)) {
           q = SUB (q);
           if (q != NO_NODE && IS (q, IDENTIFIER)) {
             if (is_identifier_or_label_global (TABLE (q), NSYMBOL (q)) == LABEL) {
               ATTRIBUTE (secondary) = JUMP;
               SUB (secondary) = q;
             }
           }
         }
       }
     } else if (IS (p, SECONDARY)) {
       NODE_T *q = SUB (p);
       if (q != NO_NODE && IS (q, PRIMARY)) {
         NODE_T *primary = q;
         q = SUB (q);
         if (q != NO_NODE && IS (q, IDENTIFIER)) {
           if (is_identifier_or_label_global (TABLE (q), NSYMBOL (q)) == LABEL) {
             ATTRIBUTE (primary) = JUMP;
             SUB (primary) = q;
           }
         }
       }
     } else if (IS (p, PRIMARY)) {
       NODE_T *q = SUB (p);
       if (q != NO_NODE && IS (q, IDENTIFIER)) {
         if (is_identifier_or_label_global (TABLE (q), NSYMBOL (q)) == LABEL) {
           make_sub (q, q, JUMP);
         }
       }
     }
     rearrange_goto_less_jumps (SUB (p));
   }
 }
     

© 2023 J.M. van der Veer

jmvdveer@xs4all.nl