--- /dev/null
+/*
+ * Copyright © 2016 Keith Packard <keithp@keithp.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#include "ao_scheme.h"
+
+int
+lambda_size(void *addr)
+{
+ (void) addr;
+ return sizeof (struct ao_scheme_lambda);
+}
+
+void
+lambda_mark(void *addr)
+{
+ struct ao_scheme_lambda *lambda = addr;
+
+ ao_scheme_poly_mark(lambda->code, 0);
+ ao_scheme_poly_mark(lambda->frame, 0);
+}
+
+void
+lambda_move(void *addr)
+{
+ struct ao_scheme_lambda *lambda = addr;
+
+ ao_scheme_poly_move(&lambda->code, 0);
+ ao_scheme_poly_move(&lambda->frame, 0);
+}
+
+const struct ao_scheme_type ao_scheme_lambda_type = {
+ .size = lambda_size,
+ .mark = lambda_mark,
+ .move = lambda_move,
+ .name = "lambda",
+};
+
+void
+ao_scheme_lambda_write(ao_poly poly)
+{
+ struct ao_scheme_lambda *lambda = ao_scheme_poly_lambda(poly);
+ struct ao_scheme_cons *cons = ao_scheme_poly_cons(lambda->code);
+
+ printf("(");
+ printf("%s", ao_scheme_args_name(lambda->args));
+ while (cons) {
+ printf(" ");
+ ao_scheme_poly_write(cons->car);
+ cons = ao_scheme_poly_cons(cons->cdr);
+ }
+ printf(")");
+}
+
+ao_poly
+ao_scheme_lambda_alloc(struct ao_scheme_cons *code, int args)
+{
+ struct ao_scheme_lambda *lambda;
+ ao_poly formal;
+ struct ao_scheme_cons *cons;
+
+ formal = ao_scheme_arg(code, 0);
+ while (formal != AO_SCHEME_NIL) {
+ switch (ao_scheme_poly_type(formal)) {
+ case AO_SCHEME_CONS:
+ cons = ao_scheme_poly_cons(formal);
+ if (ao_scheme_poly_type(cons->car) != AO_SCHEME_ATOM)
+ return ao_scheme_error(AO_SCHEME_INVALID, "formal %p is not atom", cons->car);
+ formal = cons->cdr;
+ break;
+ case AO_SCHEME_ATOM:
+ formal = AO_SCHEME_NIL;
+ break;
+ default:
+ return ao_scheme_error(AO_SCHEME_INVALID, "formal %p is not atom", formal);
+ }
+ }
+
+ ao_scheme_cons_stash(0, code);
+ lambda = ao_scheme_alloc(sizeof (struct ao_scheme_lambda));
+ code = ao_scheme_cons_fetch(0);
+ if (!lambda)
+ return AO_SCHEME_NIL;
+
+ lambda->type = AO_SCHEME_LAMBDA;
+ lambda->args = args;
+ lambda->code = ao_scheme_cons_poly(code);
+ lambda->frame = ao_scheme_frame_mark(ao_scheme_frame_current);
+ DBGI("build frame: "); DBG_POLY(lambda->frame); DBG("\n");
+ DBG_STACK();
+ return ao_scheme_lambda_poly(lambda);
+}
+
+ao_poly
+ao_scheme_do_lambda(struct ao_scheme_cons *cons)
+{
+ return ao_scheme_lambda_alloc(cons, AO_SCHEME_FUNC_LAMBDA);
+}
+
+ao_poly
+ao_scheme_do_nlambda(struct ao_scheme_cons *cons)
+{
+ return ao_scheme_lambda_alloc(cons, AO_SCHEME_FUNC_NLAMBDA);
+}
+
+ao_poly
+ao_scheme_do_macro(struct ao_scheme_cons *cons)
+{
+ return ao_scheme_lambda_alloc(cons, AO_SCHEME_FUNC_MACRO);
+}
+
+ao_poly
+ao_scheme_lambda_eval(void)
+{
+ struct ao_scheme_lambda *lambda = ao_scheme_poly_lambda(ao_scheme_v);
+ struct ao_scheme_cons *cons = ao_scheme_poly_cons(ao_scheme_stack->values);
+ struct ao_scheme_cons *code = ao_scheme_poly_cons(lambda->code);
+ ao_poly formals;
+ struct ao_scheme_frame *next_frame;
+ int args_wanted;
+ ao_poly varargs = AO_SCHEME_NIL;
+ int args_provided;
+ int f;
+ struct ao_scheme_cons *vals;
+
+ DBGI("lambda "); DBG_POLY(ao_scheme_lambda_poly(lambda)); DBG("\n");
+
+ args_wanted = 0;
+ for (formals = ao_scheme_arg(code, 0);
+ ao_scheme_is_pair(formals);
+ formals = ao_scheme_poly_cons(formals)->cdr)
+ ++args_wanted;
+ if (formals != AO_SCHEME_NIL) {
+ if (ao_scheme_poly_type(formals) != AO_SCHEME_ATOM)
+ return ao_scheme_error(AO_SCHEME_INVALID, "bad lambda form");
+ varargs = formals;
+ }
+
+ /* Create a frame to hold the variables
+ */
+ args_provided = ao_scheme_cons_length(cons) - 1;
+ if (varargs == AO_SCHEME_NIL) {
+ if (args_wanted != args_provided)
+ return ao_scheme_error(AO_SCHEME_INVALID, "need %d args, got %d", args_wanted, args_provided);
+ } else {
+ if (args_provided < args_wanted)
+ return ao_scheme_error(AO_SCHEME_INVALID, "need at least %d args, got %d", args_wanted, args_provided);
+ }
+
+ ao_scheme_poly_stash(1, varargs);
+ next_frame = ao_scheme_frame_new(args_wanted + (varargs != AO_SCHEME_NIL));
+ varargs = ao_scheme_poly_fetch(1);
+ if (!next_frame)
+ return AO_SCHEME_NIL;
+
+ /* Re-fetch all of the values in case something moved */
+ lambda = ao_scheme_poly_lambda(ao_scheme_v);
+ cons = ao_scheme_poly_cons(ao_scheme_stack->values);
+ code = ao_scheme_poly_cons(lambda->code);
+ formals = ao_scheme_arg(code, 0);
+ vals = ao_scheme_poly_cons(cons->cdr);
+
+ next_frame->prev = lambda->frame;
+ ao_scheme_frame_current = next_frame;
+ ao_scheme_stack->frame = ao_scheme_frame_poly(ao_scheme_frame_current);
+
+ for (f = 0; f < args_wanted; f++) {
+ struct ao_scheme_cons *arg = ao_scheme_poly_cons(formals);
+ DBGI("bind "); DBG_POLY(arg->car); DBG(" = "); DBG_POLY(vals->car); DBG("\n");
+ ao_scheme_frame_bind(next_frame, f, arg->car, vals->car);
+ formals = arg->cdr;
+ vals = ao_scheme_poly_cons(vals->cdr);
+ }
+ if (varargs) {
+ DBGI("bind "); DBG_POLY(varargs); DBG(" = "); DBG_POLY(ao_scheme_cons_poly(vals)); DBG("\n");
+ /*
+ * Bind the rest of the arguments to the final parameter
+ */
+ ao_scheme_frame_bind(next_frame, f, varargs, ao_scheme_cons_poly(vals));
+ } else {
+ /*
+ * Mark the cons cells from the actuals as freed for immediate re-use, unless
+ * the actuals point into the source function (nlambdas and macros), or if the
+ * stack containing them was copied as a part of a continuation
+ */
+ if (lambda->args == AO_SCHEME_FUNC_LAMBDA && !ao_scheme_stack_marked(ao_scheme_stack)) {
+ ao_scheme_stack->values = AO_SCHEME_NIL;
+ ao_scheme_cons_free(cons);
+ }
+ }
+ DBGI("eval frame: "); DBG_POLY(ao_scheme_frame_poly(next_frame)); DBG("\n");
+ DBG_STACK();
+ DBGI("eval code: "); DBG_POLY(code->cdr); DBG("\n");
+ return code->cdr;
+}
projects / fw / altos / blobdiff