Flex, Bison, C++ all in Xcode - c++

Question

I'm working through Problems with reentrant Flex and Bison. It compiles and runs just fine on my machine. What I want to do though is make use of C++ STL. Anytime I try to include a CPP header, it says it can't be found. There are only a handful of questions about this on Goog. Does anyone have a working example of this sort of setup, or a solution I might implement?
Any help would be greatly appreciated.
Thanks!
EDIT So for one reason or another, I have to add the include path of any headers in the build settings. Must be due to the custom makefile of this person's example. It's above my pay-grade. Anyway, I can now use STL libraries inside of main.
WHAT I REALLY WANT TO DO IS USE FLEX/BISON WITH CPP, AND IF I TRY TO INCLUDE STL HEADERS ANYWHERE BUT MAIN, I GET ERROR "HEADER NOT FOUND".
I can include C-headers just fine, though.

Answer 1

Here's answer from the author of another answer in the linked topic.
I have adapted that my example to work with C++.
The key points are:
I am using recent Flex / Bison: brew install flex and brew install bison. Not sure if the same will work with default OSX/Xcode's flex/bison.
Generated flex/bison files should have C++ extensions (lexer.[hpp|mm], parser.[hpp|mm]) for Xcode to pick up the C++ code.
There is a Xcode's Build Phase that runs Make.
All the relevant files follow below but I recommend you to check out the example project.
main.mm's code is
#include "parser.hpp"
#include "lexer.hpp"
extern YY_BUFFER_STATE yy_scan_string(const char * str);
extern void yy_delete_buffer(YY_BUFFER_STATE buffer);
ParserConsumer *parserConsumer = [ParserConsumer new];
char input[] = "RAINBOW UNICORN 1234 UNICORN";
YY_BUFFER_STATE state = yy_scan_string(input);
yyparse(parserConsumer);
yy_delete_buffer(state);
Lexer.lm:
%{
#include "ParserConsumer.h"
#include "parser.hpp"
#include <iostream>
#include <cstdio>
int yylex(void);
void yyerror(id <ParserConsumer> consumer, const char *msg);
%}
%option header-file = "./Parser/Generated Code/lexer.hpp"
%option outfile = "./Parser/Generated Code/lexer.mm"
%option noyywrap
NUMBER [0-9]+
STRING [A-Z]+
SPACE \x20
%%
{NUMBER} {
yylval.numericValue = (int)strtoul(yytext, NULL, 10);
std::cout << "Lexer says: Hello from C++\n";
printf("[Lexer, number] %s\n", yytext);
return Token_Number;
}
{STRING} {
yylval.stringValue = strdup(yytext);
printf("[Lexer, string] %s\n", yytext);
return Token_String;
}
{SPACE} {
// Do nothing
}
<<EOF>> {
printf("<<EOF>>\n");
return 0;
}
%%
void yyerror (id <ParserConsumer> consumer, const char *msg) {
printf("%s\n", msg);
abort();
}
Parser.ym:
%{
#include <iostream>
#include <cstdio>
#include "ParserConsumer.h"
#include "parser.hpp"
#include "lexer.hpp"
int yylex();
void yyerror(id <ParserConsumer> consumer, const char *msg);
%}
%output "Parser/Generated Code/parser.mm"
%defines "Parser/Generated Code/parser.hpp"
//%define api.pure full
%define parse.error verbose
%parse-param { id <ParserConsumer> consumer }
%union {
char *stringValue;
int numericValue;
}
%token <stringValue> Token_String
%token <numericValue> Token_Number
%%
/* http://www.tldp.org/HOWTO/Lex-YACC-HOWTO-6.html 6.2 Recursion: 'right is wrong' */
tokens: /* empty */
| tokens token
token:
Token_String {
std::cout << "Parser says: Hello from C++\n";
printf("[Parser, string] %s\n", $1);
[consumer parserDidParseString:$1];
free($1);
}
| Token_Number {
printf("[Parser, number]\n");
[consumer parserDidParseNumber:$1];
}
%%
Makefile:
generate-parser: clean flex bison
clean:
rm -rf './Parser/Generated Code'
mkdir -p './Parser/Generated Code'
flex:
# brew install flex
/usr/local/bin/flex ./Parser/Lexer.lm
bison:
# brew install bison
/usr/local/bin/bison -d ./Parser/Parser.ym