yufa.txt

一个语法词法分析器

www.pudn.com > 语法分析器.zip > 语法分析器.cpp



#include <iostream.h> 
#include <stdio.h> 
#include <string.h> 
#include <ctype.h> 
#include <iomanip.h> 
#define ID 256 
#define NUM 257 
#define ADDOP 258 
#define MULOP 259 
#define ASSIGNOP 260 
#define RELOP 261 
#define LSBRACKET 262 
#define RSBRACKET 263 
#define LMBRACKET 264 
#define RMBRACKET 265 
#define COMMA 266 
#define COLON 267 
#define DOT 268 
#define DDOT 269 
#define SEMICOLON 270 
#define IF 271 
#define ELSE 272 
#define THEN 273 
#define WHILE 274 
#define DO 275 
#define NOT 276 
#define PROGRAM 277 
#define PROCEDURE 278 
#define BEGIN 279 
#define END 280 
#define OF 281 
#define VAR 282 
#define INTEGER 283 
#define REAL 284 
#define ARRAY 285 
#define FUNCTION 286 
#define LE 288 
#define NE 289 
#define LT 290 
#define EQ 291 
#define GE 292 
#define GT 293 
#define match(name,l) doit(#name,name,l) 
struct token{ 
char label[20]; 
int id; 
int attribute; 
}; 
int next[10]; 
char num[100][20],string[20],c; 
int Line=1,length=0,len=0,index=0,sleft=0,mleft=0,lleft=0; 
char addop[3][3]={"+","-","or"}; 
char mulop[5][5]={"*","/","and","mod","div"}; 
char key[16][16]={"if","else","then","while","do","not","program","procedure","begin", 
"end","of","var","integer","real","array","function"}; 
char id[256][20]; 
FILE *fp; 
int state,start,havelooked=0; 
struct token Scanner(); 
void Loadkeyword(); 
token lookahead,looka; 
void simple_expression(); 
void expr(); 
void simple_expression(); 
void state_t(); 
void optional_statements(); 
void doit(char *s,int t,int l){ 
int i,tag,tok; 
if(lookahead.id==t){ 
if(havelooked==0) lookahead=Scanner(); 
else {lookahead=looka;havelooked=0;} 
} 
else { 
tag=0;tok=0; 
cout<<"line:"<<Line<<" syntax error:"; 
for(i=0;i<l;i++) 
if(lookahead.id==next[i]) {cout<<"possible lost "<<s<<endl;tag=1;tok=1;} 
if(tag==0){ 
looka=Scanner(); havelooked=1; 
if(t==looka.id) {cout<<"possible unwanted "<<lookahead.label<<endl;tok=1; 
lookahead=Scanner(); havelooked=0;} 
} 
if(tok==0&amt;&amt;tag==0){ 
cout<<"possible error "<<lookahead.label<<endl; 
if(havelooked==0) lookahead=Scanner(); 
else {lookahead=looka;havelooked=0;} 
} 
} 
} 
void identifier_table(){ 
if(lookahead.id==COMMA){ 
next[0]=ID; 
match(COMMA,1); 
next[0]=COMMA;next[1]=SEMICOLON; 
match(ID,2); 
identifier_table(); 
} 
else { 

} 
} 
void identifier_list(){ 
next[0]=COMMA;next[1]=SEMICOLON; 
match(ID,2); 
identifier_table(); 
} 
void standard_type(){ 
if(lookahead.id==REAL){ 
next[0]=COMMA;next[1]=SEMICOLON; 
match(REAL,2); 
} 
else { 
next[0]=COMMA;next[1]=SEMICOLON; 
match(INTEGER,2); 
} 
} 
void type(){ 
if(lookahead.id==ARRAY){ 
next[0]=LMBRACKET;match(ARRAY,1); next[0]=NUM;match(LMBRACKET,1); 
next[0]=DDOT;match(NUM,1); next[0]=NUM; match(DDOT,1); 
next[0]=RMBRACKET;match(NUM,1); next[0]=OF; match(RMBRACKET,1); 
next[0]=INTEGER;next[1]=REAL;match(OF,2); 
standard_type(); 
} 
else { 
standard_type(); 
} 
} 
void declaration(){ 
if(lookahead.id==VAR){ 
next[0]=ID; match(VAR,1); 
identifier_list(); 
next[0]=INTEGER;next[1]=REAL;next[2]=ARRAY; match(COLON,3); 
type(); 
next[0]=VAR;next[1]=FUNCTION;next[2]=PROCEDURE;next[3]=BEGIN; match(SEMICOLON,4); 
declaration(); 
} 
else { 
} 
} 
void declarations(){ 
declaration(); 
} 
void parameter_table(){ 
if(lookahead.id==SEMICOLON){ 
next[0]=ID; match(SEMICOLON,1); 
identifier_list(); 
next[0]=REAL;next[1]=INTEGER;next[2]=ARRAY; match(COLON,3); 
type(); 
parameter_table(); 
} 
else { 
} 
} 
void parameter_list(){ 
identifier_list(); 
next[0]=REAL;next[1]=INTEGER;next[2]=ARRAY; match(COLON,3); 
type(); 
parameter_table(); 
} 
void arguments(){ 
if(lookahead.id==LSBRACKET){ 
next[0]=ID;match(LSBRACKET,1); 
parameter_list(); 
next[0]=COLON;next[1]=SEMICOLON; match(RSBRACKET,2); 
} 
else { 
} 
} 
void subprogram_head(){ 
if(lookahead.id==FUNCTION){ 
next[0]=ID;match(FUNCTION,1); 
next[0]=COLON;next[1]=LSBRACKET;match(ID,2); 
arguments(); 
next[0]=INTEGER;next[1]=REAL;match(COLON,2); 
standard_type(); 
next[0]=VAR;next[1]=BEGIN; match(SEMICOLON,2); 
} 
else { 
next[0]=ID;match(PROCEDURE,1); 
next[0]=LSBRACKET;next[1]=SEMICOLON;match(ID,2); 
arguments(); 
} 
} 
void sign(){ 
} 
void expression(){ 
simple_expression(); 
expr(); 
} 
void expression_table(){ 
if(lookahead.id==COMMA){ 
next[0]=ID;next[1]=NUM;next[2]=LSBRACKET;next[3]=NOT;match(COMMA,4); 
expression(); 
expression_table(); 
} 
else{ 
} 
} 
void expression_list(){ 
expression(); 
expression_table(); 
} 
void factor_t(){ 
if(lookahead.id==LSBRACKET){ 
next[0]=ID;next[1]=NUM;next[2]=LSBRACKET;next[3]=NOT; match(LSBRACKET,4); 
expression_list(); 
next[0]=DO;next[1]=THEN;next[2]=RSBRACKET;next[3]=RELOP;next[4]=RMBRACKET; 
next[5]=COMMA; match(RSBRACKET,6); 
} 
else{ 
} 
} 
void factor(){ 
if(lookahead.id==ID){ 
next[0]=DO;next[1]=THEN;next[2]=RSBRACKET;next[3]=RELOP;next[4]=RMBRACKET; 
next[5]=COMMA; match(ID,6); 
factor_t(); 
} 
else if(lookahead.id==NUM){ 
next[0]=DO;next[1]=THEN;next[2]=RSBRACKET;next[3]=RELOP;next[4]=RMBRACKET; 
next[5]=COMMA; match(NUM,6); 
} 
else if(lookahead.id==LSBRACKET){ 
next[0]=ID;next[1]=NUM;next[2]=LSBRACKET;next[3]=NOT; match(LSBRACKET,4); 
expression(); 
next[0]=DO;next[1]=THEN;next[2]=RSBRACKET;next[3]=RELOP;next[4]=RMBRACKET; 
next[5]=COMMA;match(RSBRACKET,6); 
} 
else{ 
next[0]=ID;next[1]=NUM;next[2]=LSBRACKET;next[3]=NOT;match(NOT,4); 
factor(); 
} 
} 
void term_t(){ 
if(lookahead.id==MULOP){ 
next[0]=ID;next[1]=NUM;next[2]=LSBRACKET;next[3]=NOT;match(MULOP,4); 
factor(); 
term_t(); 
} 
else{ 
} 
} 
void term(){ 
factor(); 
term_t(); 
} 
void simple_expr(){ 
if(lookahead.id==ADDOP){ 
next[0]=ID;next[1]=NUM;next[2]=LSBRACKET;next[3]=NOT;match(ADDOP,4); 
term(); 
simple_expr(); 
} 
else { 
} 
} 
void simple_expression(){ 
if(lookahead.id==ID||lookahead.id==NUM||lookahead.id==LSBRACKET||lookahead.id==NOT){ 
term(); 
simple_expr(); 
} 
else { 
sign(); 
term(); 
simple_expr(); 
} 
} 
void expr(){ 
if(lookahead.id==RELOP){ 
next[0]=ID;next[1]=NUM;next[2]=LSBRACKET;next[3]=NOT;match(RELOP,4); 
simple_expression(); 
} 
else{ 
} 
} 
void procedure_state(){ 
if(lookahead.id==LSBRACKET){ 
next[0]=ID;next[1]=NUM;next[2]=LSBRACKET;next[3]=NOT;match(LSBRACKET,4); 
expression_list(); 
next[0]=ELSE;next[1]=SEMICOLON;match(RSBRACKET,2); 
} 
else{ 
} 
} 
void procedure_statement(){ 
next[0]=LSBRACKET;next[1]=ELSE;next[2]=SEMICOLON;match(ID,3); 
procedure_state(); 
} 
void variable_t(){ 
if(lookahead.id==LMBRACKET){ 
next[0]=ID;next[1]=NUM;next[2]=LSBRACKET;next[3]=NOT;match(LMBRACKET,4); 
expression(); 
next[0]=ASSIGNOP;match(RMBRACKET,1); 
} 
else{ 
} 
} 
void variable(){ 
next[0]=LMBRACKET;next[1]=ASSIGNOP;match(ID,2); 
variable_t(); 
} 
void state_t(){ 
if(lookahead.id==LMBRACKET||lookahead.id==ASSIGNOP){ 
variable_t(); 
next[0]=ID;next[1]=NUM;next[2]=LSBRACKET;next[3]=NOT;match(ASSIGNOP,4); 
expression(); 
} 
else { 
procedure_state(); 
} 
} 
void compound_statement(){ 
next[0]=ID;next[1]=END;next[2]=BEGIN;next[3]=IF;next[4]=WHILE;match(BEGIN,5); 
optional_statements(); 
next[0]=SEMICOLON;next[1]=DOT; match(END,2); 
} 
void statement(){ 
if(lookahead.id==ID){ 
next[0]=LSBRACKET;next[1]=LMBRACKET;next[2]=ASSIGNOP;next[3]=SEMICOLON; 
next[4]=END;match(ID,5); 
state_t(); 
} 
else if(lookahead.id==BEGIN){ 
compound_statement(); 
} 
else if(lookahead.id==IF){ 
next[0]=ID;next[1]=NUM;next[2]=LSBRACKET;next[3]=NOT;match(IF,4); 
expression(); 
next[0]=ID;next[1]=BEGIN;next[2]=IF;next[3]=WHILE;match(THEN,4); 
statement(); 
next[0]=ID;next[1]=BEGIN;next[2]=IF;next[3]=WHILE;match(ELSE,4); 
statement(); 
} 
else{ 
next[0]=ID;next[1]=NUM;next[2]=LSBRACKET;next[3]=NOT;match(WHILE,4); 
expression(); 
next[0]=ID;next[1]=BEGIN;next[2]=IF;next[3]=WHILE;match(DO,4); 
statement(); 
} 
} 
void statement_table(){ 
if(lookahead.id==SEMICOLON){ 
next[0]=ID;next[1]=BEGIN;next[2]=IF;next[3]=WHILE;match(SEMICOLON,4); 
statement(); 
statement_table(); 
} 
else{ 
} 
} 
void statement_list(){ 
statement(); 
statement_table(); 
} 
void optional_statements(){ 
if(lookahead.id==ID||lookahead.id==BEGIN||lookahead.id==IF||lookahead.id==WHILE){ 
statement_list(); 
} 
else{ 
} 
} 
void subprogram_declaration(){ 
subprogram_head(); 
declarations(); 
compound_statement(); 
} 
void sub_declarations(){ 
if(lookahead.id==FUNCTION||lookahead.id==PROCEDURE){ 
subprogram_declaration(); 
next[0]=FUNCTION;next[1]=PROCEDURE;next[2]=BEGIN;match(SEMICOLON,3); 
sub_declarations(); 
} 
else { 
} 
} 
void subprogram_declarations(){ 
sub_declarations();