parse.y:2589
NODE*
rb_compile_string(f, s, line)
    const char *f;
    VALUE s;
    int line;
{
    lex_gets = lex_get_str;
    lex_gets_ptr = 0;
    lex_input = s;
    lex_pbeg = lex_p = lex_pend = 0;
    ruby_sourceline = line - 1;
    compile_for_eval = ruby_in_eval;

    return yycompile(f, line);
}
