[Ecls-list] ecl_read_from_cstring() and ecl_read_from_cstring_safe() don't work

[Kamil Shakirov]

On Tue, 2009-08-18 at 12:00 +0200, Juan Jose Garcia-Ripoll wrote:
> On Tue, Aug 18, 2009 at 11:25 AM, Kamil Shakirov<kamils80 at gmail.com> wrote:
> > In the latest ECL 9.8.x the function c_string_to_object(s) was replaced
> > with ecl_read_from_cstring(S) and ecl_read_from_cstring_safe(S, V)
> > macros.
> 
> Yes, the intention is that there is the possibility to signal errors
> and not just ignore them.
> 
> > I tested my app with the latest CVS HEAD and found that with the correct
> > input expression, ecl_read_from_cstring(S) returns a cl_object that
> > can't be evaluated with si_safe_eval() and ecl_read_from_cstring_safe(S,
> > V) always return V. c_string_to_object(S) works as expected in 9.7.x.
> 
> I would say that is impossible because c_string_to_object is just an
> alias for ecl_read_from_string. From ecl/src/h/external.h
> 
> #define ecl_read_from_cstring(s)
> si_string_to_object(1,make_constant_base_string(s))
> #define ecl_read_from_cstring_safe(s,v)
> si_string_to_object(2,make_constant_base_string(s),(v))
> #define c_string_to_object ecl_read_from_cstring
> 

Yes, I first checked external.h before submitting this issue. After
c_string_to_object()/ecl_read_from_string() had failed I tried to use
ecl_read_from_cstring_safe() that also failed returning the second
parameter even if the input expression is correct.

I used this simple app to evaluate expressions:

/* ecl_test.c */

#include <ecl/ecl.h>
#include <stdio.h>
#include <string.h>

int main(int argc, char *argv[])
{
    char line[256];
    cl_object read_error, eval_error, form;

    cl_boot(argc, argv);
    read_error = cl_gensym(0);
    eval_error = cl_gensym(0);

    while(1) {
        printf("\nREPL> ");
        if(!fgets(line, sizeof(line), stdin)) {
            break;
        }
        line[strlen(line)-1] = '\0';

        form = ecl_read_from_cstring(line);
        /* form = ecl_read_from_cstring_safe(line, read_error); */
        if(form == read_error) {
            printf("failed to read: %s\n", line);
        }
        else {
            cl_object obj = cl_safe_eval(form, Cnil, eval_error);
            if(obj == eval_error) {
                printf("failed to evaluate: %s\n", line);
            }
            else {
                cl_object out = cl_princ_to_string(1, obj);
                printf("%s\n", (const char*)out->base_string.self);
            }
        }
    }

    cl_shutdown();
    return 0;
}

> Could you print the output of ecl_read_from_cstring() ?

If I evaluate form with ecl_read_from_cstring() I get:

REPL> (list 1 2 3)     
failed to evaluate: (list 1 2 3)

If I use ecl_read_from_cstring_safe() I get:

REPL> (list 1 2 3)
failed to read: (list 1 2 3)

In both cases it doesn't enter debugger.

>  Does
> si_string_to_object get called when you use c_string_to_object() ?

Yes, it gets called by ecl_read_from_cstring() macro.

> Juanjo
> 
-- 
--wbr.