lexer and parser

README.md

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+#Compiler Construction
+
+##Author:
+Jinglun Dong
+
+##Dependency:
+Lexer using flex
+Parser using bison
+
+##How to compile:
+$flex lexer.l
+$bison -d parser.y
+$gcc lex.yy.c parser.tab.c -o parser.out
+
+##How to run:
+$./parser.out < inputStream
+OR:
+$./parser.out inputFile.txt
+
+##Output:
+stdout for rules and symbo table goes to rule.out and symtable.out
+stderr for rules and symbo table goes to rule.err and symtable.err

README.md~

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+Lexer using flex
+Parser using bison
+
+How to compile:
+$flex lexer.l
+$bison -d parser.y
+$gcc lex.yy.c parser.tab.c -o parser.out
+
+How to run:
+$./parser.out < inputStream
+OR:
+$./parser.out inputFile.txt
+
+Output:
+stdout for rules and symbo table goes to rule.out and symtable.out
+stderr for rules and symbo table goes to rule.err and symtable.err

lexer.l

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+/*Assignment 1. Jinglun DONG*/
+%{
+#include "parser.tab.h"
+#include "parser.h"
+
+/*Symbol Table*/
+struct token entity[1000];
+
+int count = 0;     //number of tokens
+%}
+
+ID	{letter}({letter}|{digit}|_)*
+
+letter 	[A-Za-z]
+
+digit	[0-9]
+
+INT	{digit}+
+
+STR	\"[^\n"]+\"
+
+WS	[ \t\r\n]+  
+
+%%
+and 		{return(AND);}
+begin		{return(_BEGIN);}
+forward 	{return(FORWARD);}
+div       	{return(DIV);}
+do  		{return(DO);}
+else		{return(ELSE);}
+end		{return(END);}
+for		{return(FOR);}
+function	{return(FUNCTION);}
+if    	{return(IF);}
+array		{return(ARRAY);}
+mod	    {return(MOD);}
+not		{return(NOT);}
+of		{return(OF);}
+or		{return(OR);}
+procedure	{return(PROCEDURE);}
+program   {return(PROGRAM);}
+record	{return(RECORD);}
+then		{return(THEN);}
+to		{return(TO);}
+type		{return(TYPE);}
+var		{return(VAR);}
+while		{return(WHILE);}
+sym		{return(SYM);}
+
+{ID}		{yylval.num = (int)installID(); return(ID);}
+
+{INT}		{yylval.num = (int)installNum(); return(INT);}
+
+{STR}		{yylval.num = (int)installStr(); return(STR);}
+
+"."		    {yylval.num = DOT; return(DOT);}
+","     	{yylval.num = COMMA; return(COMMA);}
+":" 		{yylval.num = COLON; return(COLON);}
+";" 		{yylval.num = SEMIC; return(SEMIC);}
+":="    	{yylval.num = ASSIGN; return(ASSIGN);}
+".."    	{yylval.num = DOTDOT; return(DOTDOT);}
+"(" 		{yylval.num = LPAR; return(LPAR);}
+")" 		{yylval.num = RPAR; return(RPAR);}
+"["		    {yylval.num = LBRAC; return(LBRAC);}
+"]"		    {yylval.num = RBRAC; return(RBRAC);}
+
+
+"="         {yylval.num = EQUAL; return(EQUAL);}
+"<"         {yylval.num = LESS; return(LESS);}
+"<="        {yylval.num = LESSEQUAL; return(LESSEQUAL);}
+">"         {yylval.num = GREATER; return(GREATER);}
+">="        {yylval.num = GREATEREQUAL; return(GREATEREQUAL);}
+"<>"        {yylval.num = NOTEQUAL; return(NOTEQUAL);}
+
+"+"         {yylval.num = PLUS; return(PLUS);}
+"-"         {yylval.num = MINUS; return(MINUS);}
+"*"         {yylval.num = STAR; return(STAR);}
+
+{WS}	    {/* skip blanks and tabs */}
+
+"{"[^{}]*"}" 	{/* ignore comments */}
+
+{digit}{ID}	{return(UNKOWN);}
+
+.           {return(UNKOWN);}
+
+%%
+int yywrap(void){return 1;}
+
+int installID(){
+char* str = strdup(yytext);
+int i;
+ for(i=0;i<count;i++){
+  if(!strcmp(entity[i].value,str)){
+   return i;
+  }
+ }
+ int index = count;
+ entity[index].value = str;
+ entity[index].property = "ID";
+ count++;
+ return index;
+}
+
+int installNum(){
+ return 0;
+}
+
+int installStr(){
+ return 0;
+}
+
+/*
+int main( int argc, char **argv ){
+    ++argv, --argc;  
+    if ( argc > 0 )
+         yyin = fopen( argv[0], "r" );
+    else
+         yyin = stdin;
+    int tokenNum;
+    while(tokenNum = yylex()){
+        printf("%d\n",tokenNum);
+    }
+}
+*/
+

parser.h

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+#ifndef PARSER_H
+#define PARSER_H
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include <string.h>
+
+struct token{
+ char* property;
+ char* value;
+ char* type;
+};
+
+struct ids {
+  int index;
+  struct ids* next;
+  int depth;
+};
+
+struct ids* newid(int id, struct ids* next);
+#endif

parser.h~

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+#ifndef HEADER_H
+#define HEADER_H
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include <string.h>
+
+struct token{
+ char* property;
+ char* value;
+ char* type;
+};
+
+struct ids {
+  int index;
+  struct ids* next;
+  int depth;
+};
+
+struct ids* newid(int id, struct ids* next);
+#endif