parse.y.bak

6个不同的词法语法分析程序源代码

/****************************************************/
/* File: tiny.y                                     */
/* The TINY Yacc/Bison specification file           */
/* Compiler Construction: Principles and Practice   */
/* Kenneth C. Louden                                */
/****************************************************/
%{
#define YYPARSER /* distinguishes Yacc output from other code files */

#include "globals.h"
#include "util.h"
#include "scan.h"
#include "parse.h"
#include <stdlib.h>

#define YYSTYPE TreeNode *
static char * savedName; /* for use in assignments */
static int savedLineNo; /* ditto */
static int savedLength;
static int savedIndex;
static TreeNode * savedTree; /* stores syntax tree for later return */

%}

%token IF ELSE WHILE DO MAIN FOR GOTO CONTINUE BREAK RINT RFLOAT   
%token ID FLOAT INT 
%token ASSIGN EQ NE LT MT LE ME PLUS MINUS TIMES OVER AND OR NOT LP RP LB RB LS RS SEMI COMMA
%token ERROR 

%% /* Grammar for TINY */

program     : MAIN LP RP LB stmt_seq RB      { savedTree = $5;} 
            ;
stmt_seq    : stmt_seq SEMI stmt
                 { YYSTYPE t = $1;
                   if (t != NULL)
                   { while (t->sibling != NULL)
                        t = t->sibling;
                     t->sibling = $3;
                     $$ = $1; }
                     else $$ = $3;
                 }
            | stmt  { $$ = $1; }
            ;
stmt        : if_stmt { $$ = $1; }
            | while_stmt { $$ = $1; }
            | assign_stmt { $$ = $1; }
            | decl_stmt { $$ = $1; }
            | error  { $$ = NULL; }
            ;
if_stmt     : IF LP exp RP LB stmt_seq RB 
                 { $$ = newStmtNode(IfK);
                   $$->child[0] = $3;
                   $$->child[1] = $6;
                 }
            | IF LP exp RP LB stmt_seq RB  ELSE LB stmt_seq RB 
                 { $$ = newStmtNode(IfK);
                   $$->child[0] = $3;
                   $$->child[1] = $6;
                   $$->child[2] = $10;
                 }
            ;
while_stmt  : WHILE LP exp RP LB stmt_seq RB
                 { $$ = newStmtNode(WhileK);
                   $$->child[0] = $3;
                   $$->child[1] = $6;
                 }
            ;
assign_stmt : ID { savedName = copyString(tokenString);
                   savedLineNo = lineno; 
                 }

              ASSIGN exp
                 { $$ = newStmtNode(AssignK);
                   $$->child[0] = newExpNode(IdK);
                   $$->child[0]->attr.name =savedName;
                   $$->child[1] = $4;
                   $$->attr.name = savedName;
                   $$->lineno = savedLineNo;
                 }
            | ID { savedName = copyString(tokenString);
                   savedLineNo = lineno; }
              LS INT
                 { savedIndex = atoi(tokenString);
                  }
              RS ASSIGN exp
                 { $$ = newStmtNode(AssignK);
                   $$->child[0] = newExpNode(ArrK);
                   $$->child[0]->attr.name = savedName;
                   $$->child[0]->attr.index = savedIndex;
                   $$->child[0]->attr.length = 0;
                   
                   $$->attr.name = savedName;
                   $$->lineno = savedLineNo;
                   $$->child[1] = $8;
                 } 
            ;
decl_stmt   : type var_list 
			     { $$ = newStmtNode(DeclK);
			       $$->child[0] = $1;
			       $$->child[1] = $2;
			     }
			;
type        : RINT
				{  $$ = newTypeNode(IntK);
				} 
			| RFLOAT
			    {  $$ = newTypeNode(FloatK);
				} 
			;
var_list    : var_list COMMA var
                { YYSTYPE t = $1;
                   if (t != NULL)
                   { while (t->sibling != NULL)
                        t = t->sibling;
                     t->sibling = $3;
                     $$ = $1; }
                     else $$ = $3;
                 } 
			| var 
                {  $$ = $1;
                }
			;
var         : ID
                {  $$ = newExpNode(IdK); 
                   $$->attr.name =
                        copyString(tokenString);}	
            | ID 
            	{  savedName=
                         copyString(tokenString);
                }
              LS INT 
                {  savedLength = atoi(tokenString);
                }
              RS
                {  $$ = newExpNode(ArrK);
            	   $$->attr.name =savedName;
                   $$->attr.length = savedLength;
                }
            ;
exp         : comp_exp AND comp_exp
                 { $$ = newExpNode(OpK);
                   $$->child[0] = $1;
                   $$->child[1] = $3;
                   $$->attr.op = AND;
                  }
             |comp_exp OR comp_exp
                 { $$ = newExpNode(OpK);
                   $$->child[0] = $1;
                   $$->child[1] = $3;
                   $$->attr.op = OR;
                  }
             |NOT comp_exp
                 { $$ = newExpNode(OpK);
                   $$->child[0] = $1;
                   $$->attr.op = NOT;
                  }
            ;
comp_exp    : simple_exp LT simple_exp 
                 { $$ = newExpNode(OpK);
                   $$->child[0] = $1;
                   $$->child[1] = $3;
                   $$->attr.op = LT;
                 }
            | simple_exp MT simple_exp
                 { $$ = newExpNode(OpK);
                   $$->child[0] = $1;
                   $$->child[1] = $3;
                   $$->attr.op = MT;
                 }
            | simple_exp LE simple_exp
                 { $$ = newExpNode(OpK);
                   $$->child[0] = $1;
                   $$->child[1] = $3;
                   $$->attr.op = LE;
                 }
            | simple_exp ME simple_exp
                 { $$ = newExpNode(OpK);
                   $$->child[0] = $1;
                   $$->child[1] = $3;
                   $$->attr.op = ME;
                 }
            | simple_exp EQ simple_exp
                 { $$ = newExpNode(OpK);
                   $$->child[0] = $1;
                   $$->child[1] = $3;
                   $$->attr.op = EQ;
                 }
            | simple_exp NE simple_exp
                 { $$ = newExpNode(OpK);
                   $$->child[0] = $1;
                   $$->child[1] = $3;
                   $$->attr.op = NE;
                 }
            | simple_exp { $$ = $1; }
            ;
simple_exp  : simple_exp PLUS term 
                 { $$ = newExpNode(OpK);
                   $$->child[0] = $1;
                   $$->child[1] = $3;
                   $$->attr.op = PLUS;
                 }
            | simple_exp MINUS term
                 { $$ = newExpNode(OpK);
                   $$->child[0] = $1;
                   $$->child[1] = $3;
                   $$->attr.op = MINUS;
                 } 
            | term { $$ = $1; }
            ;
term        : term TIMES factor 
                 { $$ = newExpNode(OpK);
                   $$->child[0] = $1;
                   $$->child[1] = $3;
                   $$->attr.op = TIMES;
                 }
            | term OVER factor
                 { $$ = newExpNode(OpK);
                   $$->child[0] = $1;
                   $$->child[1] = $3;
                   $$->attr.op = OVER;
                 }
            | factor { $$ = $1; }
            ;
factor      : LP exp RP
                 { $$ = $2; }
            | INT
                 { $$ = newExpNode(IK);
                   $$->attr.val.i = atoi(tokenString);
                 }
              FLOAT
                 { $$ = newExpNode(FK);
                   $$->attr.val.f = atof(tokenString);
                 }
            | ID { $$ = newExpNode(IdK);
                   $$->attr.name =
                         copyString(tokenString);
                 }
            | ID { savedName=
                         copyString(tokenString);
                 }
              LS INT 
                 { savedIndex= atoi(tokenString); 
                 }
              RS { $$ = newExpNode(ArrK);
                   $$->attr.name = savedName;
                   $$->attr.index = savedIndex;
                 } 
              
            | error { $$ = NULL; }
            ;

%%

/*static int yyerror(char * message)
{ fprintf(listing,"Syntax error at line %d: %s\n",lineno,message);
  fprintf(listing,"Current token: ");
  printToken(yychar,tokenString);
  Error = TRUE;
  return 0;
}*/

/* yylex calls getToken to make Yacc/Bison output
 * compatible with ealier versions of the TINY scanner
 */
int yylex(void)
{ return getToken(); }

TreeNode * parse(void)
{ yyparse();
  return savedTree;
}