altos/scheme: add make-string builtin

[fw/altos] / src / scheme / ao_scheme_builtin.c

diff --git a/src/scheme/ao_scheme_builtin.c b/src/scheme/ao_scheme_builtin.c
index 0da68778eef7398164644e461d3bb3cbe93bd910..0b84a89a2b366bdb67f2cf337fa4dc2a34eac24f 100644 (file)
--- a/src/scheme/ao_scheme_builtin.c
+++ b/src/scheme/ao_scheme_builtin.c
@@ -762,17 +762,39 @@ ao_scheme_do_string_set(struct ao_scheme_cons *cons)
        val = ao_scheme_arg_int(_ao_scheme_atom_string2dset21, cons, 2);
        if (ao_scheme_exception)
                return AO_SCHEME_NIL;
+       if (!val)
+               goto fail;
        while (*string && ref) {
                ++string;
                --ref;
        }
        if (!*string)
-               return ao_scheme_error(AO_SCHEME_INVALID, "%v: string %v ref %v invalid",
-                                      _ao_scheme_atom_string2dset21,
-                                      ao_scheme_arg(cons, 0),
-                                      ao_scheme_arg(cons, 1));
+               goto fail;
        *string = val;
        return ao_scheme_int_poly(*string);
+fail:
+       return ao_scheme_error(AO_SCHEME_INVALID, "%v: %v[%v] = %v invalid",
+                              _ao_scheme_atom_string2dset21,
+                              ao_scheme_arg(cons, 0),
+                              ao_scheme_arg(cons, 1),
+                              ao_scheme_arg(cons, 2));
+}
+
+ao_poly
+ao_scheme_do_make_string(struct ao_scheme_cons *cons)
+{
+       int32_t len;
+       char    fill;
+
+       if (!ao_scheme_check_argc(_ao_scheme_atom_make2dstring, cons, 1, 2))
+               return AO_SCHEME_NIL;
+       len = ao_scheme_arg_int(_ao_scheme_atom_make2dstring, cons, 0);
+       if (ao_scheme_exception)
+               return AO_SCHEME_NIL;
+       fill = ao_scheme_opt_arg_int(_ao_scheme_atom_make2dstring, cons, 1, ' ');
+       if (ao_scheme_exception)
+               return AO_SCHEME_NIL;
+       return ao_scheme_string_poly(ao_scheme_make_string(len, fill));
 }
 
 ao_poly