I have this flex file that gets tokens from a file. For some reason i get this strange warning whenever i compile my file. However the file still compiles and i dont get why do i even get this error if the line has nothing on it, am i missing something?
Sorry if the code is too long the code itself isnt really important the important thing is why line 166 gives a warning
error:
$ flex l22_scanner.l
l22_scanner.l:166: warning, rule cannot be matched
Program:
%option c++ prefix="l22_scanner_" outfile="l22_scanner.cpp"
%option stack noyywrap yylineno 8bit debug
%{
// make relevant includes before including the parser's tab file
#include <string>
#include <stack>
#include <cdk/ast/sequence_node.h>
#include <cdk/ast/expression_node.h>
#include <cdk/ast/lvalue_node.h>
#include "l22_parser.tab.h"
// don't change this
#define yyerror LexerError
long conv_long(const std::string &s, int base = 10) {
try {
long num = std::stol(s,NULL,base);
if(num != (int) std::stol(std::to_string(num).c_str(), NULL, 10))
std::cerr << "Overflow detected";
return num;
} catch (const std::invalid_argument &e) {
std::cerr << "invalid integer: " << s << std::endl;
exit(1);
} catch (const std::out_of_range &e) {
std::cerr << "integer out of range: " << s << std::endl;
exit(1);
}
}
double conv_double(const std::string &s) {
try {
return std::stod(s, NULL);
} catch (const std::invalid_argument &e) {
std::cerr << "invalid double: " << s << std::endl;
exit(1);
} catch (const std::out_of_range &e) {
std::cerr << "double out of range: " << s << std::endl;
exit(1);
}
}
std::vector<int> indents_at_index;
std::stack<char> indent;
bool termination = false;
int idents_counter(const char* str) {
int i, counter;
i = counter = 0;
while(str[i] != ' ' && str[i] == ' ') {
if(str[i] == ' ') {
counter++;
}
i++;
}
return counter;
}
%}
%x X_STRING X_COMMENT X_NOINDENT X_CLOSE X_ENDSTR
/*TYPE "int"|"double"|"text"|"void"*/
%%
yydebug=1; set_debug(1);
^.*$ {
if(indents_at_index.empty()) {
if(idents_counter(yytext) != 0){
yyerror("wrong indentation on 1st line");
}
indents_at_index.push_back(0);
yyless(0);
}
else{
int counter = idents_counter(yytext);
if(counter < indents_at_index.back()) {
while(counter != indents_at_index.back()) {
if(counter > indents_at_index.back()) {
yyerror("wrong identation");
} else if(counter < indents_at_index.back()) {
indents_at_index.pop_back();
indent.push('}');
}
}
yyless(0);
return ';';
} else if(counter == indents_at_index.back()) {
yyless(0);
} else if(counter > indents_at_index.back()) {
indents_at_index.push_back(counter);
yyless(0);
return '{';
}
}
}
"..."$ yy_push_state(X_NOINDENT);
<X_NOINDENT>^[ t]* yy_pop_state();
<X_NOINDENT>^. yy_pop_state(); yyless(0);
<X_NOINDENT>n ;
";".*$ ; /* ignore comments */
"int" return tTYPE_INT;
"text" return tTYPE_TEXT;
"double" return tTYPE_DOUBLE;
"void" return tTYPE_VOID;
[-+*/%~<>@?=] return *yytext;
">=" return tGE;
"<=" return tLE;
"==" return tEQ;
"!=" return tNE;
"not" return tNOT;
"and" return tAND;
"or" return tOR;
"->" return tLAMBDA;
"foreign" return tFOREIGN;
"use" return tUSE;
"public" return tPUBLIC;
"var" return tVAR;
"if" return tIF;
"then" return tTHEN;
"elif" return tELIF;
"else" return tELSE;
"while" return tWHILE;
"do" return tDO;
"stop" return tSTOP;
"again" return tAGAIN;
"write" return tWRITE;
"writeln" return tWRITELN;
"return" return tRETURN;
"begin" return tBEGIN;
"end" return tEND;
"sizeof" return tSIZEOF;
"input" return tINPUT;
"null" return tNULL;
[A-Za-z][A-Za-z0-9_]* yylval.s = new std::string(yytext); return tIDENTIFIER;
" yy_push_state(X_STRING); yylval.s = new std::string("");
<X_STRING>" yy_pop_state(); return tTEXT;
<X_STRING>\" *yylval.s += '"';
<X_STRING>\\ *yylval.s += '\';
<X_STRING>\n *yylval.s += 'n';
<X_STRING>\r *yylval.s += 'r';
<X_STRING>\t *yylval.s += 't';
<X_STRING>"" yy_push_state(X_STRING);
<X_STRING>\[0-6]{1,3} *yylval.s += (char) conv_long(yytext+1,7);
<X_STRING>\0 yy_push_state(X_ENDSTR);
<X_STRING> yyerror("nullchar in string");
<X_STRING>. *yylval.s += yytext;
<X_STRING>n yyerror("newline in string");
<X_ENDSTR> yyerror("null byte in string");
<X_ENDSTR>" yy_pop_state(); yy_pop_state(); return tTEXT;
<X_ENDSTR>.|n ; /* ignore everything after */
"(*" yy_push_state(X_COMMENT);
<X_COMMENT>"(*" yy_push_state(X_COMMENT);
<X_COMMENT>"*)" yy_pop_state();
<X_COMMENT>.|n ; /*ignore comments */
[0-6]+ yylval.i = conv_long(yytext,7); return tINTEGER;
[0-9]+ yylval.i = conv_long(yytext); return tINTEGER;
[0-9]+.[0-9]+([Ee][-+]?[0-9]+)? yylval.d = conv_double(yytext); return tDOUBLE;
[0-9]+([Ee][-+]?[0-9]+) yylval.d = conv_double(yytext); return tDOUBLE;
[-+*/%()<>={}.?[],@:=] return *yytext;
[ tn]+ ; /* ignore whitespace */
. yyerror("Unknown character");
<X_CLOSE><<EOF>> {
if(!indent.empty()) {
char return_value = indent.top();
indent.pop();
yy_pop_state();
yy_push_state(X_CLOSE);
return return_value;
}
else {
yy_pop_state();
termination = true;
}
}
<<EOF>> {
if(termination) {
return 0;
}
int counter = 0;
if(counter == indents_at_index.back()){
termination = true;
return ';';
}
if(counter < indents_at_index.back()) {
while(counter != indents_at_index.back()) {
if(counter < indents_at_index.back()) {
indents_at_index.pop_back();
indent.push('}');
}
else if(counter > indents_at_index.back()) {
yyerror("wrong indentation!");
}
}
indent.push(';');
}
yy_push_state(X_CLOSE);
}
%%