From: Basile STARYNKEVITCH <basile-news@...>
Date: 2003-09-02T19:31:33+09:00
Subject: suggestion: rb_eval_string_location

Dear All Ruby implementors,

Sometimes it is useful that if an error occur in an evaluated string,
the location of the error is displayed as something more meaningful
(and more specific) than "(eval)"

May I suggest to add the following functions to the Ruby C API - add
them into eval.c (FWIW I did want them & tested them in my Guis for
ruby - see http://starynkevitch.net/Basile/guisdoc_ruby_beta.html for
more)

I believe that a bit more stuff might need to be coded for this to
work really properly - but I really think that the C coder should be
offered the possibility to set the location information (displayed in
backtraces & error messages) of the evaluated string


################################################################
/***
  evaluate a string with an explicit location (name of the "file"
          displayed on error)
***/

VALUE
rb_eval_string_location(const char *str, const char* loc)
{
    VALUE v;
    NODE *oldsrc = ruby_current_node;
    ruby_current_node = 0;
    v = eval(ruby_top_self, rb_str_new2(str), Qnil, loc, 1);
    ruby_current_node = oldsrc;
    return v;
}

/*** evaluate with protection a string with explicit location ***/
VALUE
rb_eval_string_protect_location(const char *str, const char*loc, int *state)
{
    VALUE result;		/* OK */
    int status;
    char* oldfile = ruby_sourcefile;
    int oldline = ruby_sourceline;
    PUSH_TAG(PROT_NONE);
    if ((status = EXEC_TAG()) == 0) {
        ruby_sourcefile = loc;
        ruby_sourceline = 1;
	result = rb_eval_string_location(str, loc);
    }
    POP_TAG();
    if (state) {
	*state = status;
        ruby_sourcefile = oldfile;
        ruby_sourceline = oldline;
    }
    if (status != 0) {
	return Qnil;
    }
    return result;
}
################################################################
-- 

Basile STARYNKEVITCH         http://starynkevitch.net/Basile/ 
email: basile<at>starynkevitch<dot>net 
aliases: basile<at>tunes<dot>org = bstarynk<at>nerim<dot>net
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