X-Git-Url: https://git.gag.com/?a=blobdiff_plain;f=src%2Fscheme%2Fao_scheme_lambda.c;fp=src%2Fscheme%2Fao_scheme_lambda.c;h=ec6f858c2f4fa99d95f72d8c3e01c2b93b7dd2cf;hb=195cbeec19a6a44f309a9040d727d37fe4e2ec97;hp=0000000000000000000000000000000000000000;hpb=9dbc686ad7d3289dc0f9bcf4a973f71100e02ded;p=fw%2Faltos diff --git a/src/scheme/ao_scheme_lambda.c b/src/scheme/ao_scheme_lambda.c new file mode 100644 index 00000000..ec6f858c --- /dev/null +++ b/src/scheme/ao_scheme_lambda.c @@ -0,0 +1,208 @@ +/* + * Copyright © 2016 Keith Packard + * + * 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; +}