old-ycmm.y

使用yacc和lex编写的cmm语言的词法分析和语法分析程序.

%{

#include <stdio.h>

%}
%union {
      int intvalue;
      double realvalue;
      char * str;
};

%token IDENTIFIER CONSTANT
%token GE_OP LE_OP EQ_OP NE_OP AND_OP OR_OP
%token INT REAL
%token WHILE WRITE READ IF ELSE

%nonassoc IF
%nonassoc ELSE
%right '='
%left '|'
%left '^'
%left '&'
%left '+' '-'
%left '*' '/'
%left UNARY
%left '.' '(' '['
%start program

%%

program
      : declaration_list statement_list
      ;
primary_expr
      : identifier
      | CONSTANT
      | '(' expr ')'
      ;

identifier
      : IDENTIFIER
      ;

postfix_expr
      : primary_expr
      | postfix_expr '[' expr ']'
      ;

unary_expr
      : postfix_expr
      | unary_operator cast_expr
      ;

unary_operator
      : '&'
      | '*'
      | '+'
      | '-'
      | '~'
      | '!'
      ;

cast_expr
      : unary_expr
      ;

multiplicative_expr
      : cast_expr
      | multiplicative_expr '*' multiplicative_expr
      | multiplicative_expr '/' multiplicative_expr
      ;

additive_expr
      : multiplicative_expr
      | additive_expr '+' additive_expr
      | additive_expr '-' additive_expr
      ;

shift_expr
      : additive_expr
      ;
relational_expr
      : shift_expr
      | relational_expr '<' shift_expr
      | relational_expr '>' shift_expr
      | relational_expr LE_OP shift_expr
      | relational_expr GE_OP shift_expr
      ;

equality_expr
      : relational_expr
      | equality_expr EQ_OP relational_expr
      | equality_expr NE_OP relational_expr
      ;

and_expr
      : equality_expr
      | and_expr '&' equality_expr
      ;

exclusive_or_expr
      : and_expr
      | exclusive_or_expr '^' and_expr
      ;

inclusive_or_expr
      : exclusive_or_expr
      | inclusive_or_expr '|' exclusive_or_expr
      ;

logical_and_expr
      : inclusive_or_expr
      | logical_and_expr AND_OP inclusive_or_expr
      ;

logical_or_expr
      : logical_and_expr
      | logical_or_expr OR_OP logical_and_expr
      ;

conditional_expr
      : logical_or_expr
      ;

assignment_expr
      : logical_or_expr
      | unary_expr assignment_operator assignment_expr
      ;

assignment_operator
      : '='
      ;

expr
      : assignment_expr
      | expr ',' assignment_expr
      ;

constant_expr
      : conditional_expr
      ;

declaration
      : declaration_specifiers ';'
      | declaration_specifiers init_declarator_list ';'
      ;

declaration_specifiers
      : type_specifier
      ;

init_declarator_list
      : init_declarator
      | init_declarator_list ',' init_declarator
      ;

init_declarator
      : declarator
      | declarator '=' initializer    
      ;

type_specifier
      : INT
      | REAL
      ;

declarator
      : declarator2
      ;

declarator2
      : identifier
      | declarator2 '[' ']'
      | declarator2 '[' constant_expr ']'
      ;

initializer
      : assignment_expr
      | '{' initializer_list '}'
      ;

initializer_list
      : initializer 
      | initializer_list ',' initializer 
      ;

statement
      : compound_statement
      | expression_statement
      | selection_statement
      | iteration_statement
      | io_statement
      ;

compound_statement
      : '{' '}'
      | '{' statement_list '}'
      ;

expression_statement
      : ';'
      | expr ';'
      ;

declaration_list
      : declaration
      | declaration_list declaration
      ;
statement_list
      : statement
      | statement_list statement
      ;

selection_statement
      : IF '(' expr ')' statement %prec IF
      | IF '(' expr ')' statement ELSE statement
      ;

iteration_statement
      : WHILE '(' expr ')' statement
      ;

io_statement
      : WRITE '(' expr ')' ';'
      | READ '(' identifier ')' ';'
%%

int main () {
      yyparse();
}