myparser.y

编译原理课程设计之pp2语法分析程序

%{
/****************************************************************************
myparser.y
ParserWizard generated YACC file.

Date: 2006年4月25日
****************************************************************************/
#include <ctype.h>
#include <stdio.h>
#include "lex.h"
#define YYSTYPE double /* double type for YACC stack */
%}

/////////////////////////////////////////////////////////////////////////////
// declarations section

// place any declarations here
%token 
  PROGRAM BEGIN END CONST ARRAY IF THEN ELSE 
  WHILE DO REPEAT UNTIL FOR TO READ WRITE 
  
  INTEGER REAL BOOLEAN  
  
  ID
  
  INT_CONS REAL_CONS TRUE FALSE 
  
  PLUS MINUS TIMES DIVIDE 
  EQ NEQ LT LE GT GE AND OR NOT ASSIGN
  
  COMMA COLON SEMICOLON 
  LPAR RPAR LBRACK RBRACK LBRACE RBRACE 


//preferences
%nonassoc THEN
%nonassoc ELSE		//优先级的问题，then比else低，才不会产生冲突

%left AND OR
%right NOT
%nonassoc EQ NEQ LT LE GT GE
%left PLUS MINUS
%left TIMES DIVIDE
%right UMINUS

%start prog
%%

/////////////////////////////////////////////////////////////////////////////
// rules section

// place your YACC rules here (there must be at least one)

prog	:	PROGRAM ID SEMICOLON decl BEGIN sentStr END
		;

decl	:	CONST constDef SEMICOLON
		|	varDecl SEMICOLON
		|	funcDecl	//???, delete the SEMICOLON
		;

constDef	:	ID EQ cons
			|	constDef SEMICOLON ID EQ cons
			;

cons	:	INT_CONS
		|	REAL_CONS
		|	TRUE
		|	FALSE
		;


varDecl		:	type COLON idList
			|	type COLON arrayList
			|	varDecl SEMICOLON type COLON idList
			| 	varDecl SEMICOLON type COLON arrayList
			;

type	:	INTEGER		//???
		|	REAL
		|	BOOLEAN
		;

idList	:	ID
		|	idList COMMA ID
		;

arrayList	:	ARRAY ID LBRACK dimDecl RBRACK
			|	arrayList COMMA ARRAY ID LBRACK dimDecl RBRACK	
			;

dimDecl		:	INT_CONS		//???, undefined, right_recursion??, POS_INT_CONS is not needed??
			|	dimDecl COMMA INT_CONS
			;

funcDecl	:	type ID LPAR funcParam RPAR LBRACE sentStr RBRACE		//???
			|	funcDecl type ID LPAR funcParam RPAR LBRACE sentStr RBRACE
			;

//funcDecl	:	type ID LPAR funcParam RPAR LBRACE sentStr RBRACE;

funcParam	:	type COLON ID
			|	funcParam COMMA type COLON ID
			;

sentStr	:	sent
		|	sentStr SEMICOLON sent
		;

sent	:	ID ASSIGN expr		//??? var->ID
		|	IF expr THEN sent
		|	IF expr THEN sent ELSE sent
		|	WHILE expr DO sent
		|	REPEAT sent UNTIL expr	//??? sentStr->sent
		|	FOR ID ASSIGN expr TO expr DO sent
		|	BEGIN sentStr END 
		| 	READ idList
		|	WRITE exprList
		|	funcCall
		;

exprList	:	expr
			|	exprList COMMA expr
			;

expr	:	expr EQ expr
		|	expr NEQ expr
		|	expr LT expr
		|	expr LE expr
		|	expr GT expr
		|	expr GE expr
		|	expr AND expr
		|	expr OR expr
		| 	NOT expr
		|	expr PLUS expr
		|	expr MINUS expr
		|	expr TIMES expr
		|	expr DIVIDE expr	//delete MOD
		| 	LPAR expr RPAR	
		|	MINUS expr %prec UMINUS
		| 	INT_CONS
		| 	REAL_CONS
		|	TRUE
		|	FALSE
		|	ID
		|	funcCall
		;

funcCall	:	ID LPAR funcCall_Param RPAR
			;

funcCall_Param		:	cons
					|	ID
					|	funcCall_Param COMMA cons
					|	funcCall_Param COMMA ID
					;
%%

/////////////////////////////////////////////////////////////////////////////
// programs section

void yyerror(char *s)
{
	fprintf(stderr, "error:%s\n", s);
	return;
}

int yygettoken(void)
{
	int c;
	c = word();
	/*while ((c = getchar()) == ' ');
	if (c == '.' || isdigit(c)) {
		ungetc(c, stdin);
// place your token retrieving code here
		scanf("%lf", &yylval);
		return NUMBER;
	}*/
	if(c==REAL_CONS)
		yylval = realToken;
	if(c==INT_CONS)
		yylval = intToken;
	if(c==TRUE)
		yylval = 1;
	if(c==FALSE)
		yylval = 0;
	return c;
}

int main(void)
{
	char sourcefile[20], destfile[20];
	printf("输入源文件名。\n");
	scanf("%s", sourcefile);
	fp_r = fopen(sourcefile, "r");
	printf("输入目标文件名。\n");
	scanf("%s", destfile);
	fp_w = fopen(destfile, "w");
	if(!fp_r || !fp_w)
	{
		printf("IO operation failed.\n");
		return 0;
	}

	init();	//lex.h
	return yyparse();
}