911 lines
22 KiB
C
911 lines
22 KiB
C
/*
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** Copyright (c) 2020 rxi
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**
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** Permission is hereby granted, free of charge, to any person obtaining a copy
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** of this software and associated documentation files (the "Software"), to
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** deal in the Software without restriction, including without limitation the
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** rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
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** sell copies of the Software, and to permit persons to whom the Software is
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** furnished to do so, subject to the following conditions:
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**
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** The above copyright notice and this permission notice shall be included in
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** all copies or substantial portions of the Software.
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**
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** THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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** IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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** FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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** AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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** LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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** FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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** IN THE SOFTWARE.
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*/
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#include <string.h>
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#include "fe.h"
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#define unused(x) ( (void) (x) )
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#define car(x) ( (x)->car.o )
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#define cdr(x) ( (x)->cdr.o )
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#define tag(x) ( (x)->car.c )
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#define isnil(x) ( (x) == &nil )
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#define type(x) ( tag(x) & 0x1 ? tag(x) >> 2 : FE_TPAIR )
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#define settype(x,t) ( tag(x) = (t) << 2 | 1 )
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#define number(x) ( (x)->cdr.n )
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#define prim(x) ( (x)->cdr.c )
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#define cfunc(x) ( (x)->cdr.f )
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#ifdef GINT
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#define strbuf(x) ( (char *)&(x)->car )
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#else
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#define strbuf(x) ( &(x)->car.c + 1 )
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#endif
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#define STRBUFSIZE ( (int) sizeof(fe_Object*) - 1 )
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#define GCMARKBIT ( 0x2 )
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#define GCSTACKSIZE ( 256 )
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enum {
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P_LET, P_SET, P_IF, P_FN, P_MAC, P_WHILE, P_QUOTE, P_AND, P_OR, P_DO, P_CONS,
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P_CAR, P_CDR, P_SETCAR, P_SETCDR, P_LIST, P_NOT, P_IS, P_ATOM, P_PRINT, P_LT,
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P_LTE, P_ADD, P_SUB, P_MUL, P_DIV, P_MAX
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};
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static const char *primnames[] = {
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"let", "=", "if", "fn", "mac", "while", "quote", "and", "or", "do", "cons",
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"car", "cdr", "setcar", "setcdr", "list", "not", "is", "atom", "print", "<",
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"<=", "+", "-", "*", "/"
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};
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static const char *typenames[] = {
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"pair", "free", "nil", "number", "symbol", "string",
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"func", "macro", "prim", "cfunc", "ptr"
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};
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typedef union {
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fe_Object *o;
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fe_CFunc f;
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fe_Number n;
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#ifdef GINT
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struct __attribute__((__packed__)) { char _[3]; char c; };
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#else
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char c;
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#endif
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} Value;
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struct fe_Object { Value car, cdr; };
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struct fe_Context {
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fe_Handlers handlers;
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fe_Object *gcstack[GCSTACKSIZE];
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int gcstack_idx;
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fe_Object *objects;
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int object_count;
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fe_Object *calllist;
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fe_Object *freelist;
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fe_Object *symlist;
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fe_Object *t;
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int nextchr;
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};
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static fe_Object nil = {{ (void*) (FE_TNIL << 2 | 1) }, { NULL }};
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fe_Handlers* fe_handlers(fe_Context *ctx) {
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return &ctx->handlers;
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}
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void fe_error(fe_Context *ctx, const char *msg) {
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fe_Object *cl = ctx->calllist;
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/* reset context state */
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ctx->calllist = &nil;
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/* do error handler */
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if (ctx->handlers.error) { ctx->handlers.error(ctx, msg, cl); }
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/* error handler returned -- print error and traceback, exit */
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#ifndef GINT
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fprintf(stderr, "error: %s\n", msg);
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#endif
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for (; !isnil(cl); cl = cdr(cl)) {
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char buf[64];
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fe_tostring(ctx, car(cl), buf, sizeof(buf));
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#ifndef GINT
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fprintf(stderr, "=> %s\n", buf);
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#endif
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}
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exit(EXIT_FAILURE);
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}
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fe_Object* fe_nextarg(fe_Context *ctx, fe_Object **arg) {
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fe_Object *a = *arg;
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if (type(a) != FE_TPAIR) {
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if (isnil(a)) { fe_error(ctx, "too few arguments"); }
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fe_error(ctx, "dotted pair in argument list");
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}
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*arg = cdr(a);
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return car(a);
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}
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static fe_Object* checktype(fe_Context *ctx, fe_Object *obj, int type) {
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char buf[64];
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if (type(obj) != type) {
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sprintf(buf, "expected %s, got %s", typenames[type], typenames[type(obj)]);
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fe_error(ctx, buf);
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}
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return obj;
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}
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int fe_type(fe_Context *ctx, fe_Object *obj) {
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unused(ctx);
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return type(obj);
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}
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int fe_isnil(fe_Context *ctx, fe_Object *obj) {
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unused(ctx);
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return isnil(obj);
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}
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void fe_pushgc(fe_Context *ctx, fe_Object *obj) {
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if (ctx->gcstack_idx == GCSTACKSIZE) {
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fe_error(ctx, "gc stack overflow");
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}
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ctx->gcstack[ctx->gcstack_idx++] = obj;
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}
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void fe_restoregc(fe_Context *ctx, int idx) {
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ctx->gcstack_idx = idx;
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}
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int fe_savegc(fe_Context *ctx) {
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return ctx->gcstack_idx;
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}
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void fe_mark(fe_Context *ctx, fe_Object *obj) {
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fe_Object *car;
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begin:
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if (tag(obj) & GCMARKBIT) { return; }
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car = car(obj); /* store car before modifying it with GCMARKBIT */
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tag(obj) |= GCMARKBIT;
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switch (type(obj)) {
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case FE_TPAIR:
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fe_mark(ctx, car);
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/* fall through */
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case FE_TFUNC: case FE_TMACRO: case FE_TSYMBOL: case FE_TSTRING:
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obj = cdr(obj);
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goto begin;
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case FE_TPTR:
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if (ctx->handlers.mark) { ctx->handlers.mark(ctx, obj); }
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break;
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}
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}
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static void collectgarbage(fe_Context *ctx) {
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int i;
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/* mark */
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for (i = 0; i < ctx->gcstack_idx; i++) {
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fe_mark(ctx, ctx->gcstack[i]);
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}
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fe_mark(ctx, ctx->symlist);
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/* sweep and unmark */
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for (i = 0; i < ctx->object_count; i++) {
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fe_Object *obj = &ctx->objects[i];
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if (type(obj) == FE_TFREE) { continue; }
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if (~tag(obj) & GCMARKBIT) {
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if (type(obj) == FE_TPTR && ctx->handlers.gc) {
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ctx->handlers.gc(ctx, obj);
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}
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settype(obj, FE_TFREE);
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cdr(obj) = ctx->freelist;
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ctx->freelist = obj;
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} else {
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tag(obj) &= ~GCMARKBIT;
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}
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}
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}
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static int equal(fe_Object *a, fe_Object *b) {
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if (a == b) { return 1; }
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if (type(a) != type(b)) { return 0; }
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if (type(a) == FE_TNUMBER) { return number(a) == number(b); }
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if (type(a) == FE_TSTRING) {
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for (; !isnil(a); a = cdr(a), b = cdr(b)) {
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if (car(a) != car(b)) { return 0; }
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}
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return a == b;
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}
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return 0;
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}
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static int streq(fe_Object *obj, const char *str) {
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while (!isnil(obj)) {
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int i;
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for (i = 0; i < STRBUFSIZE; i++) {
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if (strbuf(obj)[i] != *str) { return 0; }
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if (*str) { str++; }
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}
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obj = cdr(obj);
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}
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return *str == '\0';
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}
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static fe_Object* object(fe_Context *ctx) {
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fe_Object *obj;
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/* do gc if freelist has no more objects */
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if (isnil(ctx->freelist)) {
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collectgarbage(ctx);
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if (isnil(ctx->freelist)) { fe_error(ctx, "out of memory"); }
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}
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/* get object from freelist and push to the gcstack */
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obj = ctx->freelist;
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ctx->freelist = cdr(obj);
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fe_pushgc(ctx, obj);
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return obj;
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}
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fe_Object* fe_cons(fe_Context *ctx, fe_Object *car, fe_Object *cdr) {
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fe_Object *obj = object(ctx);
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car(obj) = car;
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cdr(obj) = cdr;
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return obj;
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}
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fe_Object* fe_bool(fe_Context *ctx, int b) {
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return b ? ctx->t : &nil;
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}
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fe_Object* fe_number(fe_Context *ctx, fe_Number n) {
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fe_Object *obj = object(ctx);
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settype(obj, FE_TNUMBER);
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number(obj) = n;
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return obj;
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}
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static fe_Object* buildstring(fe_Context *ctx, fe_Object *tail, int chr) {
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if (!tail || strbuf(tail)[STRBUFSIZE - 1] != '\0') {
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fe_Object *obj = fe_cons(ctx, NULL, &nil);
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settype(obj, FE_TSTRING);
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if (tail) {
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cdr(tail) = obj;
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ctx->gcstack_idx--;
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}
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tail = obj;
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}
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strbuf(tail)[strlen(strbuf(tail))] = chr;
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return tail;
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}
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fe_Object* fe_string(fe_Context *ctx, const char *str) {
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fe_Object *obj = buildstring(ctx, NULL, '\0');
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fe_Object *tail = obj;
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while (*str) {
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tail = buildstring(ctx, tail, *str++);
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}
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return obj;
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}
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fe_Object* fe_symbol(fe_Context *ctx, const char *name) {
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fe_Object *obj;
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/* try to find in symlist */
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for (obj = ctx->symlist; !isnil(obj); obj = cdr(obj)) {
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if (streq(car(cdr(car(obj))), name)) {
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return car(obj);
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}
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}
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/* create new object, push to symlist and return */
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obj = object(ctx);
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settype(obj, FE_TSYMBOL);
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cdr(obj) = fe_cons(ctx, fe_string(ctx, name), &nil);
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ctx->symlist = fe_cons(ctx, obj, ctx->symlist);
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return obj;
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}
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fe_Object* fe_cfunc(fe_Context *ctx, fe_CFunc fn) {
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fe_Object *obj = object(ctx);
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settype(obj, FE_TCFUNC);
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cfunc(obj) = fn;
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return obj;
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}
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fe_Object* fe_ptr(fe_Context *ctx, void *ptr) {
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fe_Object *obj = object(ctx);
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settype(obj, FE_TPTR);
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cdr(obj) = ptr;
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return obj;
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}
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fe_Object* fe_list(fe_Context *ctx, fe_Object **objs, int n) {
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fe_Object *res = &nil;
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while (n--) {
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res = fe_cons(ctx, objs[n], res);
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}
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return res;
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}
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fe_Object* fe_car(fe_Context *ctx, fe_Object *obj) {
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if (isnil(obj)) { return obj; }
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return car(checktype(ctx, obj, FE_TPAIR));
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}
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fe_Object* fe_cdr(fe_Context *ctx, fe_Object *obj) {
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if (isnil(obj)) { return obj; }
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return cdr(checktype(ctx, obj, FE_TPAIR));
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}
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static void writestr(fe_Context *ctx, fe_WriteFn fn, void *udata, const char *s) {
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while (*s) { fn(ctx, udata, *s++); }
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}
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void fe_write(fe_Context *ctx, fe_Object *obj, fe_WriteFn fn, void *udata, int qt) {
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char buf[32];
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switch (type(obj)) {
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case FE_TNIL:
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writestr(ctx, fn, udata, "nil");
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break;
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case FE_TNUMBER:
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sprintf(buf, "%.7g", number(obj));
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writestr(ctx, fn, udata, buf);
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break;
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case FE_TPAIR:
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fn(ctx, udata, '(');
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for (;;) {
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fe_write(ctx, car(obj), fn, udata, 1);
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obj = cdr(obj);
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if (type(obj) != FE_TPAIR) { break; }
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fn(ctx, udata, ' ');
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}
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if (!isnil(obj)) {
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writestr(ctx, fn, udata, " . ");
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fe_write(ctx, obj, fn, udata, 1);
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}
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fn(ctx, udata, ')');
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break;
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case FE_TSYMBOL:
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fe_write(ctx, car(cdr(obj)), fn, udata, 0);
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break;
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case FE_TSTRING:
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if (qt) { fn(ctx, udata, '"'); }
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while (!isnil(obj)) {
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int i;
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for (i = 0; i < STRBUFSIZE && strbuf(obj)[i]; i++) {
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if (qt && strbuf(obj)[i] == '"') { fn(ctx, udata, '\\'); }
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fn(ctx, udata, strbuf(obj)[i]);
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}
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obj = cdr(obj);
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}
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if (qt) { fn(ctx, udata, '"'); }
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break;
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default:
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sprintf(buf, "[%s %p]", typenames[type(obj)], (void*) obj);
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writestr(ctx, fn, udata, buf);
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break;
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}
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}
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static void writefp(fe_Context *ctx, void *udata, char chr) {
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unused(ctx);
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/* fputc(chr, udata); */
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}
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void fe_writefp(fe_Context *ctx, fe_Object *obj, FILE *fp) {
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fe_write(ctx, obj, writefp, fp, 0);
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}
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typedef struct { char *p; int n; } CharPtrInt;
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static void writebuf(fe_Context *ctx, void *udata, char chr) {
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CharPtrInt *x = udata;
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unused(ctx);
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if (x->n) { *x->p++ = chr; x->n--; }
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}
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int fe_tostring(fe_Context *ctx, fe_Object *obj, char *dst, int size) {
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CharPtrInt x;
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x.p = dst;
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x.n = size - 1;
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fe_write(ctx, obj, writebuf, &x, 0);
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*x.p = '\0';
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return size - x.n - 1;
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}
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fe_Number fe_tonumber(fe_Context *ctx, fe_Object *obj) {
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return number(checktype(ctx, obj, FE_TNUMBER));
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}
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void* fe_toptr(fe_Context *ctx, fe_Object *obj) {
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return cdr(checktype(ctx, obj, FE_TPTR));
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}
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static fe_Object* getbound(fe_Object *sym, fe_Object *env) {
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/* try to find in environment */
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for (; !isnil(env); env = cdr(env)) {
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fe_Object *x = car(env);
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if (car(x) == sym) { return x; }
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}
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/* return global */
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return cdr(sym);
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}
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void fe_set(fe_Context *ctx, fe_Object *sym, fe_Object *v) {
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unused(ctx);
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cdr(getbound(sym, &nil)) = v;
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}
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static fe_Object rparen;
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static fe_Object* read_(fe_Context *ctx, fe_ReadFn fn, void *udata) {
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const char *delimiter = " \n\t\r();";
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fe_Object *v, *res, **tail;
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fe_Number n;
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int chr, gc;
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char buf[64], *p;
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/* get next character */
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chr = ctx->nextchr ? ctx->nextchr : fn(ctx, udata);
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ctx->nextchr = '\0';
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/* skip whitespace */
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while (chr && strchr(" \n\t\r", chr)) {
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chr = fn(ctx, udata);
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}
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switch (chr) {
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case '\0':
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return NULL;
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case ';':
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while (chr && chr != '\n') { chr = fn(ctx, udata); }
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return read_(ctx, fn, udata);
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case ')':
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return &rparen;
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case '(':
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res = &nil;
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tail = &res;
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gc = fe_savegc(ctx);
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fe_pushgc(ctx, res); /* to cause error on too-deep nesting */
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while ( (v = read_(ctx, fn, udata)) != &rparen ) {
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if (v == NULL) { fe_error(ctx, "unclosed list"); }
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if (type(v) == FE_TSYMBOL && streq(car(cdr(v)), ".")) {
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/* dotted pair */
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*tail = fe_read(ctx, fn, udata);
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} else {
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/* proper pair */
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*tail = fe_cons(ctx, v, &nil);
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tail = &cdr(*tail);
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}
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fe_restoregc(ctx, gc);
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fe_pushgc(ctx, res);
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}
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return res;
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case '\'':
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v = fe_read(ctx, fn, udata);
|
|
if (!v) { fe_error(ctx, "stray '''"); }
|
|
return fe_cons(ctx, fe_symbol(ctx, "quote"), fe_cons(ctx, v, &nil));
|
|
|
|
case '"':
|
|
res = buildstring(ctx, NULL, '\0');
|
|
v = res;
|
|
chr = fn(ctx, udata);
|
|
while (chr != '"') {
|
|
if (chr == '\0') { fe_error(ctx, "unclosed string"); }
|
|
if (chr == '\\') {
|
|
chr = fn(ctx, udata);
|
|
if (strchr("nrt", chr)) { chr = strchr("n\nr\rt\t", chr)[1]; }
|
|
}
|
|
v = buildstring(ctx, v, chr);
|
|
chr = fn(ctx, udata);
|
|
}
|
|
return res;
|
|
|
|
default:
|
|
p = buf;
|
|
do {
|
|
if (p == buf + sizeof(buf) - 1) { fe_error(ctx, "symbol too long"); }
|
|
*p++ = chr;
|
|
chr = fn(ctx, udata);
|
|
} while (chr && !strchr(delimiter, chr));
|
|
*p = '\0';
|
|
ctx->nextchr = chr;
|
|
n = strtod(buf, &p); /* try to read as number */
|
|
if (p != buf && strchr(delimiter, *p)) { return fe_number(ctx, n); }
|
|
if (!strcmp(buf, "nil")) { return &nil; }
|
|
return fe_symbol(ctx, buf);
|
|
}
|
|
}
|
|
|
|
|
|
fe_Object* fe_read(fe_Context *ctx, fe_ReadFn fn, void *udata) {
|
|
fe_Object* obj = read_(ctx, fn, udata);
|
|
if (obj == &rparen) { fe_error(ctx, "stray ')'"); }
|
|
return obj;
|
|
}
|
|
|
|
|
|
static char readfp(fe_Context *ctx, void *udata) {
|
|
int chr;
|
|
unused(ctx);
|
|
/* return (chr = fgetc(udata)) == EOF ? '\0' : chr; */
|
|
return '\0';
|
|
}
|
|
|
|
fe_Object* fe_readfp(fe_Context *ctx, FILE *fp) {
|
|
return fe_read(ctx, readfp, fp);
|
|
}
|
|
|
|
|
|
static fe_Object* eval(fe_Context *ctx, fe_Object *obj, fe_Object *env, fe_Object **bind);
|
|
|
|
static fe_Object* evallist(fe_Context *ctx, fe_Object *lst, fe_Object *env) {
|
|
fe_Object *res = &nil;
|
|
fe_Object **tail = &res;
|
|
while (!isnil(lst)) {
|
|
*tail = fe_cons(ctx, eval(ctx, fe_nextarg(ctx, &lst), env, NULL), &nil);
|
|
tail = &cdr(*tail);
|
|
}
|
|
return res;
|
|
}
|
|
|
|
|
|
static fe_Object* dolist(fe_Context *ctx, fe_Object *lst, fe_Object *env) {
|
|
fe_Object *res = &nil;
|
|
int save = fe_savegc(ctx);
|
|
while (!isnil(lst)) {
|
|
fe_restoregc(ctx, save);
|
|
fe_pushgc(ctx, lst);
|
|
fe_pushgc(ctx, env);
|
|
res = eval(ctx, fe_nextarg(ctx, &lst), env, &env);
|
|
}
|
|
return res;
|
|
}
|
|
|
|
|
|
static fe_Object* argstoenv(fe_Context *ctx, fe_Object *prm, fe_Object *arg, fe_Object *env) {
|
|
while (!isnil(prm)) {
|
|
if (type(prm) != FE_TPAIR) {
|
|
env = fe_cons(ctx, fe_cons(ctx, prm, arg), env);
|
|
break;
|
|
}
|
|
env = fe_cons(ctx, fe_cons(ctx, car(prm), fe_car(ctx, arg)), env);
|
|
prm = cdr(prm);
|
|
arg = fe_cdr(ctx, arg);
|
|
}
|
|
return env;
|
|
}
|
|
|
|
|
|
#define evalarg() eval(ctx, fe_nextarg(ctx, &arg), env, NULL)
|
|
|
|
#define arithop(op) { \
|
|
fe_Number x = fe_tonumber(ctx, evalarg()); \
|
|
while (!isnil(arg)) { \
|
|
x = x op fe_tonumber(ctx, evalarg()); \
|
|
} \
|
|
res = fe_number(ctx, x); \
|
|
}
|
|
|
|
#define numcmpop(op) { \
|
|
va = checktype(ctx, evalarg(), FE_TNUMBER); \
|
|
vb = checktype(ctx, evalarg(), FE_TNUMBER); \
|
|
res = fe_bool(ctx, number(va) op number(vb)); \
|
|
}
|
|
|
|
|
|
static fe_Object* eval(fe_Context *ctx, fe_Object *obj, fe_Object *env, fe_Object **newenv) {
|
|
fe_Object *fn, *arg, *res;
|
|
fe_Object cl, *va, *vb;
|
|
int n, gc;
|
|
|
|
if (type(obj) == FE_TSYMBOL) { return cdr(getbound(obj, env)); }
|
|
if (type(obj) != FE_TPAIR) { return obj; }
|
|
|
|
car(&cl) = obj, cdr(&cl) = ctx->calllist;
|
|
ctx->calllist = &cl;
|
|
|
|
gc = fe_savegc(ctx);
|
|
fn = eval(ctx, car(obj), env, NULL);
|
|
arg = cdr(obj);
|
|
res = &nil;
|
|
|
|
switch (type(fn)) {
|
|
case FE_TPRIM:
|
|
switch (prim(fn)) {
|
|
case P_LET:
|
|
va = checktype(ctx, fe_nextarg(ctx, &arg), FE_TSYMBOL);
|
|
if (newenv) {
|
|
*newenv = fe_cons(ctx, fe_cons(ctx, va, evalarg()), env);
|
|
}
|
|
break;
|
|
|
|
case P_SET:
|
|
va = checktype(ctx, fe_nextarg(ctx, &arg), FE_TSYMBOL);
|
|
cdr(getbound(va, env)) = evalarg();
|
|
break;
|
|
|
|
case P_IF:
|
|
while (!isnil(arg)) {
|
|
va = evalarg();
|
|
if (!isnil(va)) {
|
|
res = isnil(arg) ? va : evalarg();
|
|
break;
|
|
}
|
|
if (isnil(arg)) { break; }
|
|
arg = cdr(arg);
|
|
}
|
|
break;
|
|
|
|
case P_FN: case P_MAC:
|
|
va = fe_cons(ctx, env, arg);
|
|
fe_nextarg(ctx, &arg);
|
|
res = object(ctx);
|
|
settype(res, prim(fn) == P_FN ? FE_TFUNC : FE_TMACRO);
|
|
cdr(res) = va;
|
|
break;
|
|
|
|
case P_WHILE:
|
|
va = fe_nextarg(ctx, &arg);
|
|
n = fe_savegc(ctx);
|
|
while (!isnil(eval(ctx, va, env, NULL))) {
|
|
dolist(ctx, arg, env);
|
|
fe_restoregc(ctx, n);
|
|
}
|
|
break;
|
|
|
|
case P_QUOTE:
|
|
res = fe_nextarg(ctx, &arg);
|
|
break;
|
|
|
|
case P_AND:
|
|
while (!isnil(arg) && !isnil(res = evalarg()));
|
|
break;
|
|
|
|
case P_OR:
|
|
while (!isnil(arg) && isnil(res = evalarg()));
|
|
break;
|
|
|
|
case P_DO:
|
|
res = dolist(ctx, arg, env);
|
|
break;
|
|
|
|
case P_CONS:
|
|
va = evalarg();
|
|
res = fe_cons(ctx, va, evalarg());
|
|
break;
|
|
|
|
case P_CAR:
|
|
res = fe_car(ctx, evalarg());
|
|
break;
|
|
|
|
case P_CDR:
|
|
res = fe_cdr(ctx, evalarg());
|
|
break;
|
|
|
|
case P_SETCAR:
|
|
va = checktype(ctx, evalarg(), FE_TPAIR);
|
|
car(va) = evalarg();
|
|
break;
|
|
|
|
case P_SETCDR:
|
|
va = checktype(ctx, evalarg(), FE_TPAIR);
|
|
cdr(va) = evalarg();
|
|
break;
|
|
|
|
case P_LIST:
|
|
res = evallist(ctx, arg, env);
|
|
break;
|
|
|
|
case P_NOT:
|
|
res = fe_bool(ctx, isnil(evalarg()));
|
|
break;
|
|
|
|
case P_IS:
|
|
va = evalarg();
|
|
res = fe_bool(ctx, equal(va, evalarg()));
|
|
break;
|
|
|
|
case P_ATOM:
|
|
res = fe_bool(ctx, fe_type(ctx, evalarg()) != FE_TPAIR);
|
|
break;
|
|
|
|
case P_PRINT:
|
|
while (!isnil(arg)) {
|
|
#ifndef GINT
|
|
fe_writefp(ctx, evalarg(), stdout);
|
|
if (!isnil(arg)) { printf(" "); }
|
|
#else
|
|
evalarg();
|
|
unused(isnil(arg));
|
|
#endif
|
|
}
|
|
#ifndef GINT
|
|
printf("\n");
|
|
#endif
|
|
break;
|
|
|
|
case P_LT: numcmpop(<); break;
|
|
case P_LTE: numcmpop(<=); break;
|
|
case P_ADD: arithop(+); break;
|
|
case P_SUB: arithop(-); break;
|
|
case P_MUL: arithop(*); break;
|
|
case P_DIV: arithop(/); break;
|
|
}
|
|
break;
|
|
|
|
case FE_TCFUNC:
|
|
res = cfunc(fn)(ctx, evallist(ctx, arg, env));
|
|
break;
|
|
|
|
case FE_TFUNC:
|
|
arg = evallist(ctx, arg, env);
|
|
va = cdr(fn); /* (env params ...) */
|
|
vb = cdr(va); /* (params ...) */
|
|
res = dolist(ctx, cdr(vb), argstoenv(ctx, car(vb), arg, car(va)));
|
|
break;
|
|
|
|
case FE_TMACRO:
|
|
va = cdr(fn); /* (env params ...) */
|
|
vb = cdr(va); /* (params ...) */
|
|
/* replace caller object with code generated by macro and re-eval */
|
|
*obj = *dolist(ctx, cdr(vb), argstoenv(ctx, car(vb), arg, car(va)));
|
|
fe_restoregc(ctx, gc);
|
|
ctx->calllist = cdr(&cl);
|
|
return eval(ctx, obj, env, NULL);
|
|
|
|
default:
|
|
fe_error(ctx, "tried to call non-callable value");
|
|
}
|
|
|
|
fe_restoregc(ctx, gc);
|
|
fe_pushgc(ctx, res);
|
|
ctx->calllist = cdr(&cl);
|
|
return res;
|
|
}
|
|
|
|
|
|
fe_Object* fe_eval(fe_Context *ctx, fe_Object *obj) {
|
|
return eval(ctx, obj, &nil, NULL);
|
|
}
|
|
|
|
|
|
fe_Context* fe_open(void *ptr, int size) {
|
|
int i, save;
|
|
fe_Context *ctx;
|
|
|
|
/* init context struct */
|
|
ctx = ptr;
|
|
memset(ctx, 0, sizeof(fe_Context));
|
|
ptr = (char*) ptr + sizeof(fe_Context);
|
|
size -= sizeof(fe_Context);
|
|
|
|
/* init objects memory region */
|
|
ctx->objects = (fe_Object*) ptr;
|
|
ctx->object_count = size / sizeof(fe_Object);
|
|
|
|
/* init lists */
|
|
ctx->calllist = &nil;
|
|
ctx->freelist = &nil;
|
|
ctx->symlist = &nil;
|
|
|
|
/* populate freelist */
|
|
for (i = 0; i < ctx->object_count; i++) {
|
|
fe_Object *obj = &ctx->objects[i];
|
|
settype(obj, FE_TFREE);
|
|
cdr(obj) = ctx->freelist;
|
|
ctx->freelist = obj;
|
|
}
|
|
|
|
/* init objects */
|
|
ctx->t = fe_symbol(ctx, "t");
|
|
fe_set(ctx, ctx->t, ctx->t);
|
|
|
|
/* register built in primitives */
|
|
save = fe_savegc(ctx);
|
|
for (i = 0; i < P_MAX; i++) {
|
|
fe_Object *v = object(ctx);
|
|
settype(v, FE_TPRIM);
|
|
prim(v) = i;
|
|
fe_set(ctx, fe_symbol(ctx, primnames[i]), v);
|
|
fe_restoregc(ctx, save);
|
|
}
|
|
|
|
return ctx;
|
|
}
|
|
|
|
|
|
void fe_close(fe_Context *ctx) {
|
|
/* clear gcstack and symlist; makes all objects unreachable */
|
|
ctx->gcstack_idx = 0;
|
|
ctx->symlist = &nil;
|
|
collectgarbage(ctx);
|
|
}
|
|
|
|
|
|
#ifdef FE_STANDALONE
|
|
|
|
#include <setjmp.h>
|
|
|
|
static jmp_buf toplevel;
|
|
static char buf[64000];
|
|
|
|
static void onerror(fe_Context *ctx, const char *msg, fe_Object *cl) {
|
|
unused(ctx), unused(cl);
|
|
#ifndef GINT
|
|
fprintf(stderr, "error: %s\n", msg);
|
|
#endif
|
|
longjmp(toplevel, -1);
|
|
}
|
|
|
|
|
|
int main(int argc, char **argv) {
|
|
int gc;
|
|
fe_Object *obj;
|
|
FILE *volatile fp = stdin;
|
|
fe_Context *ctx = fe_open(buf, sizeof(buf));
|
|
|
|
/* init input file */
|
|
if (argc > 1) {
|
|
fp = fopen(argv[1], "rb");
|
|
if (!fp) { fe_error(ctx, "could not open input file"); }
|
|
}
|
|
|
|
if (fp == stdin) { fe_handlers(ctx)->error = onerror; }
|
|
gc = fe_savegc(ctx);
|
|
setjmp(toplevel);
|
|
|
|
/* re(p)l */
|
|
for (;;) {
|
|
fe_restoregc(ctx, gc);
|
|
#ifndef GINT
|
|
if (fp == stdin) { printf("> "); }
|
|
#endif
|
|
if (!(obj = fe_readfp(ctx, fp))) { break; }
|
|
obj = fe_eval(ctx, obj);
|
|
#ifndef GINT
|
|
if (fp == stdin) { fe_writefp(ctx, obj, stdout); printf("\n"); }
|
|
#endif
|
|
}
|
|
|
|
return EXIT_SUCCESS;
|
|
}
|
|
|
|
#endif
|