altos/scheme: Add start/end args to vector->list

This is an r7rs extension which allows you to extract a subset of the
vector.

Signed-off-by: Keith Packard <keithp@keithp.com>

diff --git a/src/scheme/ao_scheme.h b/src/scheme/ao_scheme.h
index d4c9bc05051d15c3222c8ed9564ba71ccb177e68..428533b00222db2914952d6dab1a8ea791e689a5 100644 (file)
--- a/src/scheme/ao_scheme.h
+++ b/src/scheme/ao_scheme.h
@@ -808,7 +808,7 @@ struct ao_scheme_vector *
 ao_scheme_list_to_vector(struct ao_scheme_cons *cons);
 
 struct ao_scheme_cons *
-ao_scheme_vector_to_list(struct ao_scheme_vector *vector);
+ao_scheme_vector_to_list(struct ao_scheme_vector *vector, int start, int end);
 
 extern const struct ao_scheme_type     ao_scheme_vector_type;
 

diff --git a/src/scheme/ao_scheme_builtin.c b/src/scheme/ao_scheme_builtin.c
index e2532c98746a331ae248ace4f825ab41c4d1d874..0da68778eef7398164644e461d3bb3cbe93bd910 100644 (file)
--- a/src/scheme/ao_scheme_builtin.c
+++ b/src/scheme/ao_scheme_builtin.c
@@ -105,17 +105,23 @@ ao_scheme_check_argc(ao_poly name, struct ao_scheme_cons *cons, int min, int max
        return _ao_scheme_bool_true;
 }
 
-ao_poly
-ao_scheme_arg(struct ao_scheme_cons *cons, int argc)
+static ao_poly
+ao_scheme_opt_arg(struct ao_scheme_cons *cons, int argc, ao_poly def)
 {
-       if (!cons)
-               return AO_SCHEME_NIL;
-       while (argc--) {
+       for (;;) {
                if (!cons)
-                       return AO_SCHEME_NIL;
+                       return def;
+               if (argc == 0)
+                       return cons->car;
                cons = ao_scheme_cons_cdr(cons);
+               argc--;
        }
-       return cons->car;
+}
+
+ao_poly
+ao_scheme_arg(struct ao_scheme_cons *cons, int argc)
+{
+       return ao_scheme_opt_arg(cons, argc, AO_SCHEME_NIL);
 }
 
 ao_poly
@@ -140,6 +146,18 @@ ao_scheme_arg_int(ao_poly name, struct ao_scheme_cons *cons, int argc)
        return i;
 }
 
+static int32_t
+ao_scheme_opt_arg_int(ao_poly name, struct ao_scheme_cons *cons, int argc, int def)
+{
+       ao_poly         p = ao_scheme_opt_arg(cons, argc, ao_scheme_int_poly(def));
+       bool            fail = false;
+       int32_t         i = ao_scheme_poly_integer(p, &fail);
+
+       if (fail)
+               (void) ao_scheme_error(AO_SCHEME_INVALID, "%v: arg %d invalid type %v", name, argc, p);
+       return i;
+}
+
 ao_poly
 ao_scheme_do_car(struct ao_scheme_cons *cons)
 {
@@ -1120,11 +1138,21 @@ ao_scheme_do_list_to_vector(struct ao_scheme_cons *cons)
 ao_poly
 ao_scheme_do_vector_to_list(struct ao_scheme_cons *cons)
 {
-       if (!ao_scheme_check_argc(_ao_scheme_atom_vector2d3elist, cons, 1, 1))
+       int     start, end;
+
+       if (!ao_scheme_check_argc(_ao_scheme_atom_vector2d3elist, cons, 1, 3))
                return AO_SCHEME_NIL;
        if (!ao_scheme_check_argt(_ao_scheme_atom_vector2d3elist, cons, 0, AO_SCHEME_VECTOR, 0))
                return AO_SCHEME_NIL;
-       return ao_scheme_cons_poly(ao_scheme_vector_to_list(ao_scheme_poly_vector(ao_scheme_arg(cons, 0))));
+       start = ao_scheme_opt_arg_int(_ao_scheme_atom_vector2d3elist, cons, 1, ao_scheme_int_poly(0));
+       if (ao_scheme_exception)
+               return AO_SCHEME_NIL;
+       end = ao_scheme_opt_arg_int(_ao_scheme_atom_vector2d3elist, cons, 2, ao_scheme_int_poly(-1));
+       if (ao_scheme_exception)
+               return AO_SCHEME_NIL;
+       return ao_scheme_cons_poly(ao_scheme_vector_to_list(ao_scheme_poly_vector(ao_scheme_arg(cons, 0)),
+                                                           start,
+                                                           end));
 }
 
 ao_poly

diff --git a/src/scheme/ao_scheme_vector.c b/src/scheme/ao_scheme_vector.c
index afdc89a86e880087f98fd2842d3c29bf7d307019..083823f3097a1a6318ce267c9bf7dc82b8aa0e08 100644 (file)
--- a/src/scheme/ao_scheme_vector.c
+++ b/src/scheme/ao_scheme_vector.c
@@ -159,13 +159,19 @@ ao_scheme_list_to_vector(struct ao_scheme_cons *cons)
 }
 
 struct ao_scheme_cons *
-ao_scheme_vector_to_list(struct ao_scheme_vector *vector)
+ao_scheme_vector_to_list(struct ao_scheme_vector *vector, int start, int end)
 {
-       unsigned int            i;
+       int                     i;
        uint16_t                length = vector->length;
        struct ao_scheme_cons   *cons = NULL;
 
-       for (i = length; i-- > 0;) {
+       if (end == -1)
+               end = length;
+       if (start < 0)
+               start = 0;
+       if (end > length)
+               end = length;
+       for (i = end; i-- > start;) {
                ao_scheme_vector_stash(vector);
                cons = ao_scheme_cons_cons(vector->vals[i], ao_scheme_cons_poly(cons));
                vector = ao_scheme_vector_fetch();