demo3-lex.lpp

/* vim: set filetype=lex: */
%option noyywrap
%option prefix="demo3"
%option reentrant
%option warn nodefault
%option stack
%option bison-bridge bison-locations

%x STRING_ESCAPE

%top {
typedef union YYSTYPE YYSTYPE;
typedef struct YYLTYPE YYLTYPE;
}
%{
#include "demo3-parse.hpp"
%}

/* options to get rid of compiler warnings */
%option noinput nounput noyy_top_state noyyalloc noyyrealloc noyyfree

%{
    #include <cstdlib>

    // Hack to get rid of a compiler warning in yy_fatal_error
    // since %option noyy_fatal_error doesn't (and can't) work.
    #define fprintf yyscanner, fprintf

    // These are, relatively speaking, not a hack.
    void *yyalloc(size_t size, yyscan_t yyscanner)
    {
        (void) yyscanner;
        return malloc(size);
    }

    void *yyrealloc(void *ptr, size_t size, yyscan_t yyscanner)
    {
        (void) yyscanner;
        return realloc(ptr, size);
    }

    void yyfree(void *ptr, yyscan_t yyscanner)
    {
        (void) yyscanner;
        free(ptr);
    }
%}

%%

\n          { return NEWLINE; }
\\          { yy_push_state(STRING_ESCAPE, yyscanner); }
.           { yylval->c = yytext[0]; return CHAR; }
<STRING_ESCAPE>{
    \\      { yy_pop_state(yyscanner); yylval->c = '\\'; return CHAR; }
    \n      { yy_pop_state(yyscanner); yylval->c = '\n'; return CHAR; }
    .       { abort(); }
}

%%
/* empty 3rd section */