Tiny語言編譯器開發之語法分析（利…

採用自底向上的LR分析方法，Yacc輸入文件yyparser.y如下：

%{
#define YYPARSER

#include "globals.h"
#include "util.h"
#include "scan.h"
#include "parse.h"

#define YYSTYPE TreeNode *
static char * savedName;
static int savedLineNo; 
static TreeNode * savedTree;

%}

%token IF THEN ELSE END REPEAT UNTIL READ WRITE
%token ID NUM
%token ASSIGN EQ LT PLUS MINUS TIMES OVER LPAREN RPAREN SEMI
%token ERROR

%%

program     : stmt_seq
                 { savedTree = $1;}
            ;
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; }
            | repeat_stmt { $$ = $1; }
            | assign_stmt { $$ = $1; }
            | read_stmt { $$ = $1; }