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>
#include <string.h>
#include "tree.h"
#include "c-tree.h"

%}
%start program

%union {
      long itype;
      union tree_node * ttype;
      enum tree_code code;
      char * filename;
      int lineno;
}

%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 <code> '='
%left <code> OR_OP
%left <code> AND_OP
%left <code> '>' '<' EQ_OP NE_OP LE_OP GE_OP
%left <code> '+' '-'
%left <code> '*' '/' '%'
%right <code> UNARY
%left <code> '.' '(' '['

%type <code> unop
%type <ttype> IDENTIFIER primary CONSTANT expr expr_no_commas

%%

program
      : decls fndefs
      ;

fndefs
      : fndef
      | fndefs fndef;

fndef
      : typed_declspecs declarator compstmt

unop
      : '-'
        {
            $$ = NEGATE_EXPR;
        }
      | '+'
        {
            $$ = CONVERT_EXPR;
        }
      | '~'
        {
            $$ = ADDR_EXPR;
        }
      | '!'
        {
            $$ = TRUTH_NOT_EXPR;
        }

expr
      : nonnull_exprlist
      ;

exprlist
      : /* empty */
      | nonnull_exprlist
      ;

nonnull_exprlist
      : expr_no_commas
      | nonnull_exprlist ',' expr_no_commas
      ;

unary_expr
      : primary 
      | unop cast_expr %prec UNARY 
      ;

cast_expr
      : unary_expr 
      ;

expr_no_commas
      : cast_expr
      | expr_no_commas '+' expr_no_commas
      | expr_no_commas '-' expr_no_commas
      | expr_no_commas '*' expr_no_commas
      | expr_no_commas '/' expr_no_commas
      | expr_no_commas '%' expr_no_commas
      | expr_no_commas '=' expr_no_commas
      | expr_no_commas '<' expr_no_commas
      | expr_no_commas '>' expr_no_commas
      | expr_no_commas EQ_OP expr_no_commas
      | expr_no_commas NE_OP expr_no_commas
      | expr_no_commas LE_OP expr_no_commas
      | expr_no_commas GE_OP expr_no_commas
      | expr_no_commas AND_OP expr_no_commas
      | expr_no_commas OR_OP expr_no_commas

primary
      : IDENTIFIER 
        {
            $$ = $1; 
            printf("identifier:%s\n",$1->identifier.name);
        }
      | CONSTANT 
        {
            $$ = $1;
            if (TREE_CODE($1) == REAL_CST)
                  printf("real:%f\n",$1->real_cst.value);
            else if (TREE_CODE($1) == INTEGER_CST)
                  printf("int:%d\n",$1->int_cst.value);
        } 
      | '(' expr ')'
        {
            $$ = $2;
        }
      | primary '[' expr ']'
      | primary '(' exprlist ')'
      ;

lineno_decl
      :decl
      ;

decls
      : lineno_decl
      | decls lineno_decl
      ;

decl
      : typed_declspecs initdecls ';'
      ;

typed_declspecs
      : typespec
      ;

typespec
      : INT
      | REAL
      ;

initdecls
      : initdcl
      | initdecls ',' initdcl
      ;

initdcl
      : declarator '=' init
      | declarator
      ;

init
      : expr_no_commas
      | '{' '}'
      | '{' initlist '}'
      | '{' initlist ',' '}'

initlist
      : init
      | initlist ',' init
      ;

declarator
      : notype_declarator
      ;

notype_declarator
      : IDENTIFIER
      | notype_declarator '[' expr ']'
      | notype_declarator '[' ']'
      | notype_declarator '(' parmlist_or_identifiers
      | '(' notype_declarator ')'
      ;

stmts
      : lineno_stmt_or_label
      | stmts lineno_stmt_or_label
      ;

lineno_stmt_or_label
      : save_filename save_lineno stmt_or_label
      ;

stmt_or_label
      : stmt
      | label
      ;

label
      : IDENTIFIER ':'
      ;

xstmts
      : 
      | stmts
      ;

compstmt
      : '{' decls xstmts '}'
      | '{' xstmts '}'
      ;

simple_if
      : if_prefix lineno_labeled_stmt
      ;

if_prefix
      : IF '(' expr ')'
      ;

save_filename
      :
      ;

save_lineno
      :
      ;

lineno_labeled_stmt
      : save_filename save_lineno stmt
      ;

stmt
      : compstmt                                
      | expr ';'                                
      | simple_if ELSE lineno_labeled_stmt      
      | simple_if %prec IF                      
      | WHILE '(' expr ')' lineno_labeled_stmt  
      | WRITE '(' expr ')' ';'                 
      | READ '(' identifiers ')' ';'          

parmlist_or_identifiers
      : parms ')'
      | identifiers ')'
      | ')'
      ;

parms
      : parm
      | parms ',' parm
      ;

parm
      : typed_declspecs notype_declarator
      ;

identifiers
      : IDENTIFIER
      | identifiers ',' IDENTIFIER
      ;
%%

int main () {
      yyparse();
}