词法分析示例程序（C语言编写，针对PL/0语言）
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2009-05-16
13:31:41
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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define NORW 13 /* of reserved words */
#define TXMAX 100 /* length of identifier table */
#define NMAX 14 /* max number of digits in numbers */
#define AL 10 /* length of identifiers */
#define AMAX 2047 /* maxinum address */
#define LEVMAX 3 /* max depth of block nesting */
#define CXMAX 200 /* size of code array */
#define STACKSIZE 500
char *symbol[32]= {"nul","ident","number","plus","minus","times","slash","oddsym",
"eql","neq","lss","leq","gtr","geq","lparen","rparen","comma",
"semicolon","period","becomes","beginsym","endsym","ifsym",
"thensym","whilesym","writesym","readsym","dosym","callsym",
"constsym","varsym","procsym"}; /* type of symbols */
char *word[NORW]={"begin","call","const","do","end","if","odd","procedure",
"read","then","var","while","write"}; /* table of reserved words */
char *wsym[NORW]={ "beginsym","callsym","constsym","dosym","endsym","ifsym",
"oddsym","procsym","readsym","thensym","varsym","whilesym","writesym"};
char *mnemonic[8]= {"lit","opr","lod","sto","cal","ini","jmp","jpc"};
char ch; /* last char read */
char id[AL+1]; /*last identifier read */
char sym[10]; /* last symbol read */
char line[81];
char a[AL+1],fname[AL+1];
enum object{constant,variable,procedur};
enum object kind;
enum fct{lit,opr,lod,sto,cal,ini,jmp,jpc};
enum listswitcher{false,true}; /*true set list object code */
enum listswitcher listswitch;
FILE *fa;
FILE *fa1, *fa2;
FILE *fin, *fout;
int num; /* last number read */
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