A.13 Grammar

Below is a recapitulation of the grammar that was given throughout the earlier part of this appendix. It has exactly the same content, but is in different order. The grammar has undefined terminal symbols integer-constant, character-constant, floating-constant, identifier, string, and enumeration-constant; the typewriter style words and symbols are terminals given literally. This grammar can be transformed mechanically into input acceptable for an automatic parser-generator. Besides adding whatever syntactic marking is used to indicate alternatives in productions, it is necessary to expand the ``one of'' constructions, and (depending on the rules of the parser-generator) to duplicate each production with an opt symbol, once with the symbol and once without. With one further change, namely deleting the production typedef-name: identifier and making typedef-name a terminal symbol, this grammar is acceptable to the YACC parser-generator. It has only one conflict, generated by the if-else ambiguity.     translation-unit:       external-declaration       translation-unit external-declaration     external-declaration:       function-definition       declaration     function-definition:       declaration-specifiersopt declarator declaration-listopt compound-statement     declaration:       declaration-specifiers init-declarator-listopt;     declaration-list:       declaration       declaration-list declaration     declaration-specifiers:       storage-class-specifier declaration-specifiersopt       type-specifier declaration-specifiersopt       type-qualifier declaration-specifiersopt     storage-class specifier: one of       auto register static extern typedef     type specifier: one of       void char short int long float double signed       unsigned struct-or-union-specifier enum-specifier typedef-name     type-qualifier: one of       const volatile     struct-or-union-specifier:       struct-or-union identifieropt { struct-declaration-list }       struct-or-union identifier     struct-or-union: one of       struct union     struct-declaration-list:       struct declaration       struct-declaration-list struct declaration     init-declarator-list:       init-declarator       init-declarator-list, init-declarator     init-declarator:       declarator       declarator = initializer     struct-declaration:       specifier-qualifier-list struct-declarator-list;     specifier-qualifier-list:       type-specifier specifier-qualifier-listopt       type-qualifier specifier-qualifier-listopt     struct-declarator-list:       struct-declarator       struct-declarator-list , struct-declarator     struct-declarator:       declarator       declaratoropt : constant-expression     enum-specifier:       enum identifieropt { enumerator-list }       enum identifier     enumerator-list:       enumerator       enumerator-list , enumerator     enumerator:       identifier       identifier = constant-expression     declarator:       pointeropt direct-declarator     direct-declarator:       identifier       (declarator)       direct-declarator [ constant-expressionopt ]       direct-declarator ( parameter-type-list )       direct-declarator ( identifier-listopt )     pointer:       * type-qualifier-listopt       * type-qualifier-listopt pointer     type-qualifier-list:       type-qualifier       type-qualifier-list type-qualifier     parameter-type-list:       parameter-list       parameter-list , ...     parameter-list:       parameter-declaration       parameter-list , parameter-declaration     parameter-declaration:       declaration-specifiers declarator       declaration-specifiers abstract-declaratoropt     identifier-list:       identifier       identifier-list , identifier     initializer:       assignment-expression       { initializer-list }       { initializer-list , }     initializer-list:       initializer       initializer-list , initializer     type-name:       specifier-qualifier-list abstract-declaratoropt     abstract-declarator:       pointer       pointeropt direct-abstract-declarator     direct-abstract-declarator:       ( abstract-declarator )       direct-abstract-declaratoropt [constant-expressionopt]       direct-abstract-declaratoropt (parameter-type-listopt)     typedef-name:       identifier     statement:       labeled-statement       expression-statement       compound-statement       selection-statement       iteration-statement       jump-statement     labeled-statement:       identifier : statement       case constant-expression : statement       default : statement     expression-statement:       expressionopt;     compound-statement:       { declaration-listopt statement-listopt }     statement-list:       statement       statement-list statement     selection-statement:       if (expression) statement       if (expression) statement else statement       switch (expression) statement     iteration-statement:       while (expression) statement       do statement while (expression);       for (expressionopt; expressionopt; expressionopt) statement     jump-statement:       goto identifier;       continue;       break;       return expressionopt;     expression:       assignment-expression       expression , assignment-expression     assignment-expression:       conditional-expression       unary-expression assignment-operator assignment-expression     assignment-operator: one of       = *= /= %= += -= <<= >>= &= ^= |=     conditional-expression:       logical-OR-expression       logical-OR-expression ? expression : conditional-expression     constant-expression:       conditional-expression     logical-OR-expression:       logical-AND-expression       logical-OR-expression || logical-AND-expression     logical-AND-expression:       inclusive-OR-expression       logical-AND-expression && inclusive-OR-expression     inclusive-OR-expression:       exclusive-OR-expression       inclusive-OR-expression | exclusive-OR-expression     exclusive-OR-expression:       AND-expression       exclusive-OR-expression ^ AND-expression     AND-expression:       equality-expression       AND-expression & equality-expression     equality-expression:       relational-expression       equality-expression == relational-expression       equality-expression != relational-expression     relational-expression:       shift-expression       relational-expression < shift-expression       relational-expression > shift-expression       relational-expression <= shift-expression       relational-expression >= shift-expression     shift-expression:       additive-expression       shift-expression << additive-expression       shift-expression >> additive-expression     additive-expression:       multiplicative-expression       additive-expression + multiplicative-expression       additive-expression - multiplicative-expression     multiplicative-expression:       multiplicative-expression * cast-expression       multiplicative-expression / cast-expression       multiplicative-expression % cast-expression     cast-expression:       unary expression       (type-name) cast-expression     unary-expression:       postfix expression       ++unary expression       --unary expression       unary-operator cast-expression       sizeof unary-expression       sizeof (type-name)     unary operator: one of       & * + - ~ !     postfix-expression:       primary-expression       postfix-expression[expression]       postfix-expression(argument-expression-listopt)       postfix-expression.identifier       postfix-expression->+identifier       postfix-expression++       postfix-expression--     primary-expression:       identifier       constant       string       (expression)     argument-expression-list:       assignment-expression       assignment-expression-list , assignment-expression     constant:       integer-constant       character-constant       floating-constant       enumeration-constant The following grammar for the preprocessor summarizes the structure of control lines, but is not suitable for mechanized parsing. It includes the symbol text, which means ordinary program text, non-conditional preprocessor control lines, or complete preprocessor conditional instructions.     control-line:       # define identifier token-sequence       # define identifier(identifier, ... , identifier) token-sequence       # undef identifier       # include <filename>       # include "filename"       # line constant "filename"       # line constant       # error token-sequenceopt       # pragma token-sequenceopt       #       preprocessor-conditional     preprocessor-conditional:       if-line text elif-parts else-partopt #endif     if-line:       # if constant-expression       # ifdef identifier       # ifndef identifier     elif-parts:       elif-line text       elif-partsopt     elif-line:       # elif constant-expression     else-part:       else-line text     else-line:       #else