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mes/mes.c
Jan Nieuwenhuizen b63444d919 mes.c: barf on unknown symbols.
2016-07-23 11:51:06 +02:00

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/*
* Mes --- Maxwell Equations of Software
* Copyright © 2016 Jan Nieuwenhuizen <janneke@gnu.org>
*
* This file is part of Mes.
*
* Mes 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; either version 3 of the License, or (at
* your option) any later version.
*
* Mes 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 Mes. If not, see <http://www.gnu.org/licenses/>.
*/
// (setq comment-start "//")
// (setq comment-end "")
/*
* The Maxwell Equations of Software -- John McCarthy page 13
* http://www.softwarepreservation.org/projects/LISP/book/LISP%201.5%20Programmers%20Manual.pdf
*/
#define _GNU_SOURCE
#include <assert.h>
#include <ctype.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <stdbool.h>
#define DEBUG 0
#define MES_FULL 1
enum type {CHAR, MACRO, NUMBER, PAIR, STRING, SYMBOL, VALUES, VECTOR,
FUNCTION0, FUNCTION1, FUNCTION2, FUNCTION3, FUNCTIONn};
struct scm_t;
typedef struct scm_t* (*function0_t) (void);
typedef struct scm_t* (*function1_t) (struct scm_t*);
typedef struct scm_t* (*function2_t) (struct scm_t*, struct scm_t*);
typedef struct scm_t* (*function3_t) (struct scm_t*, struct scm_t*, struct scm_t*);
typedef struct scm_t* (*functionn_t) (struct scm_t*);
typedef struct scm_t {
enum type type;
union {
char *name;
struct scm_t* car;
int length;
};
union {
int value;
function0_t function0;
function1_t function1;
function2_t function2;
function3_t function3;
functionn_t functionn;
struct scm_t* cdr;
struct scm_t* macro;
struct scm_t** vector;
};
} scm;
#define MES_C 1
#include "mes.h"
scm *display_helper (scm*, bool, char*, bool);
bool
symbol_eq (scm *x, char *s)
{
return x->type == SYMBOL && !strcmp (x->name, s);
}
scm scm_nil = {SYMBOL, "()"};
scm scm_dot = {SYMBOL, "."};
scm scm_t = {SYMBOL, "#t"};
scm scm_f = {SYMBOL, "#f"};
scm scm_unspecified = {SYMBOL, "*unspecified*"};
scm symbol_closure = {SYMBOL, "*lambda*"};
scm symbol_circ = {SYMBOL, "*circ*"};
scm symbol_lambda = {SYMBOL, "lambda"};
scm symbol_begin = {SYMBOL, "begin"};
scm symbol_list = {SYMBOL, "list"};
scm symbol_cond = {SYMBOL, "cond"};
scm symbol_quote = {SYMBOL, "quote"};
scm symbol_quasiquote = {SYMBOL, "quasiquote"};
scm symbol_unquote = {SYMBOL, "unquote"};
scm symbol_unquote_splicing = {SYMBOL, "unquote-splicing"};
scm symbol_call_with_values = {SYMBOL, "call-with-values"};
scm symbol_current_module = {SYMBOL, "current-module"};
scm symbol_define = {SYMBOL, "define"};
scm symbol_define_macro = {SYMBOL, "define-macro"};
scm symbol_set_x = {SYMBOL, "set!"};
// PRIMITIVES
scm *
atom_p (scm *x)
{
return x->type == PAIR ? &scm_f : &scm_t;
}
scm *
car (scm *x)
{
assert (x->type == PAIR);
return x->car;
}
scm *
cdr (scm *x)
{
assert (x->type == PAIR);
return x->cdr;
}
scm *
cons (scm *x, scm *y)
{
scm *p = malloc (sizeof (scm));
p->type = PAIR;
p->car = x;
p->cdr = y;
return p;
}
scm *
eq_p (scm *x, scm *y)
{
return (x == y
|| (x->type == CHAR && y->type == CHAR
&& x->value == y->value)
|| (x->type == NUMBER && y->type == NUMBER
&& x->value == y->value)
// FIXME: alist lookup symbols
|| (atom_p (x) == &scm_t
&& atom_p (y) == &scm_t
&& x->type != CHAR
&& y->type != CHAR
&& x->type != NUMBER
&& y->type != NUMBER
&& x->type != STRING
&& y->type != STRING
&& x->type != VECTOR
&& y->type != VECTOR
&& !strcmp (x->name, y->name)))
? &scm_t : &scm_f;
}
scm *
macro_p (scm *x)
{
return x->type == MACRO ? &scm_t : &scm_f;
}
scm *
null_p (scm *x)
{
return eq_p (x, &scm_nil);
}
scm *
pair_p (scm *x)
{
return x->type == PAIR ? &scm_t : &scm_f;
}
scm *
set_cdr_x (scm *x, scm *e)
{
assert (x->type == PAIR);
x->cdr = e;
return &scm_unspecified;
}
scm *
set_x (scm *x, scm *e, scm *a)
{
return set_cdr_x (assq (x, a), e);
}
scm *
set_env_x (scm *x, scm *e, scm *a)
{
return set_cdr_x (assq (x, a), e);
}
scm *
quote (scm *x)
{
return cons (&symbol_quote, x);
}
scm *
quasiquote (scm *x)
{
return cons (&symbol_quasiquote, x);
}
scm *
unquote (scm *x) //int must not add to environment
{
return cons (&symbol_unquote, x);
}
scm *unquote (scm *x);
scm scm_unquote = {FUNCTION1, .name="unquote", .function1=&unquote};
scm *
unquote_splicing (scm *x) //int must not add to environment
{
return cons (&symbol_unquote_splicing, x);
}
scm *unquote_splicing (scm *x);
scm scm_unquote_splicing = {FUNCTION1, .name="unquote-splicing", .function1=&unquote_splicing};
//Library functions
// Derived, non-primitives
scm *caar (scm *x) {return car (car (x));}
scm *cadr (scm *x) {return car (cdr (x));}
scm *cdar (scm *x) {return cdr (car (x));}
scm *cddr (scm *x) {return cdr (cdr (x));}
scm *caadr (scm *x) {return car (car (cdr (x)));}
scm *caddr (scm *x) {return car (cdr (cdr (x)));}
scm *cdadr (scm *x) {return cdr (car (cdr (x)));}
scm *cadar (scm *x) {return car (cdr (car (x)));}
scm *cddar (scm *x) {return cdr (cdr (car (x)));}
scm *cdddr (scm *x) {return cdr (cdr (cdr (x)));}
scm *
pairlis (scm *x, scm *y, scm *a)
{
if (x == &scm_nil)
return a;
if (atom_p (x) == &scm_t)
return cons (cons (x, y), a);
return cons (cons (car (x), car (y)),
pairlis (cdr (x), cdr (y), a));
}
scm *
assq (scm *x, scm *a)
{
if (a == &scm_nil) {
#if DEBUG
printf ("alist miss: %s\n", x->name);
#endif
return &scm_f;
}
if (eq_p (caar (a), x) == &scm_t)
return car (a);
return assq (x, cdr (a));
}
scm *
apply_env (scm *fn, scm *x, scm *a)
{
#if DEBUG
printf ("\napply_env fn=");
display (fn);
printf (" x=");
display (x);
puts ("");
#endif
scm *macro;
if (atom_p (fn) != &scm_f)
{
if (fn == &symbol_current_module) return a;
if (eq_p (fn, &symbol_call_with_values) == &scm_t)
return call (&scm_call_with_values_env, append2 (x, cons (a, &scm_nil)));
if (builtin_p (fn) == &scm_t)
return call (fn, x);
}
else if (car (fn) == &symbol_lambda)
return eval (cons (&symbol_begin, cddr (fn)), pairlis (cadr (fn), x, a));
else if (car (fn) == &symbol_closure) {
scm *args = caddr (fn);
scm *body = cdddr (fn);
a = cdadr (fn);
return eval (cons (&symbol_begin, body), pairlis (args, x, a));
}
else if ((macro = lookup_macro (car (fn), a)) != &scm_f) {
scm *r = apply_env (eval (macro, a), cdr (fn), a);
scm *e = eval (r, a);
return apply_env (e, x, a);
}
scm *efn = eval (fn, a);
if (efn->type == NUMBER || efn == &scm_f || efn == &scm_t) assert (!"apply bool");
return apply_env (efn, x, a);
}
scm *make_symbol (char const *s);
scm *
eval (scm *e, scm *a)
{
#if DEBUG
printf ("\neval e=");
display (e);
puts ("");
#endif
scm *macro;
if (e->type == SYMBOL) {
scm *y = assq (e, a);
if (y == &scm_f) {
//return e;
printf ("eval: no such symbol: %s\n", e->name);
assert (!"unknown symbol");
}
return cdr (y);
}
else if (pair_p (e) == &scm_f)
return e;
else if (atom_p (car (e)) == &scm_t)
{
if (car (e) == &symbol_quote)
return cadr (e);
if (car (e) == &symbol_begin)
{
scm *body = cdr (e);
scm *defines = &scm_nil;
while (body != &scm_nil) {
e = car (body);
body = cdr (body);
if (e->type == PAIR
&& (eq_p (car (e), &symbol_define) == &scm_t
|| eq_p (car (e), &symbol_define_macro) == &scm_t)) {
defines = append2 (defines, cons (def (e), &scm_nil));
e = &scm_unspecified;
}
else break;
}
a = append2 (defines, a);
while (defines != &scm_nil) {
scm *name = caar (defines);
scm *entry = assq (name, a);
scm *x = cdar (defines);
set_cdr_x (entry, cdr (define (x, a)));
defines = cdr (defines);
}
scm *fubar = cons (&scm_dot, &scm_dot);
scm *r = eval (e, cons (fubar, a));
if (r->type == PAIR && macro_p (cdr (r)))
a = cons (r, a); // macros defining macros...
if (body == &scm_nil) return r;
return eval (cons (&symbol_begin, body), a);
}
if (car (e) == &symbol_lambda)
return make_closure (cadr (e), cddr (e), a);
if (car (e) == &symbol_closure)
return e;
if (car (e) == &symbol_unquote)
return eval (cadr (e), a);
if (car (e) == &symbol_quasiquote)
return eval_quasiquote (cadr (e), add_unquoters (a));
if (car (e) == &symbol_cond)
return evcon (cdr (e), a);
if (eq_p (car (e), &symbol_define_macro) == &scm_t)
return define (e, a);
if ((macro = lookup_macro (car (e), a)) != &scm_f)
return eval (apply_env (macro, cdr (e), a), a);
if (car (e) == &symbol_set_x)
return set_env_x (cadr (e), eval (caddr (e), a), a);
}
return apply_env (car (e), evlis (cdr (e), a), a);
}
scm *
evcon (scm *c, scm *a)
{
if (c == &scm_nil) return &scm_unspecified;
scm *clause = car (c);
scm *expr = eval (car (clause), a);
if (expr != &scm_f) {
if (cdr (clause) == &scm_nil)
return expr;
if (cddr (clause) == &scm_nil)
return eval (cadr (clause), a);
eval (cadr (clause), a);
return evcon (cons (cons (&scm_t, cddr (clause)), &scm_nil), a);
}
return evcon (cdr (c), a);
}
scm *
evlis (scm *m, scm *a)
{
if (m == &scm_nil) return &scm_nil;
if (m->type != PAIR) return eval (m, a);
scm *e = eval (car (m), a);
return cons (e, evlis (cdr (m), a));
}
scm *
eval_quasiquote (scm *e, scm *a)
{
if (e == &scm_nil) return e;
else if (atom_p (e) == &scm_t) return e;
else if (eq_p (car (e), &symbol_unquote) == &scm_t)
return eval (cadr (e), a);
else if (e->type == PAIR && e->car->type == PAIR
&& eq_p (caar (e), &symbol_unquote_splicing) == &scm_t)
return append2 (eval (cadar (e), a), eval_quasiquote (cdr (e), a));
return cons (eval_quasiquote (car (e), a), eval_quasiquote (cdr (e), a));
}
//Helpers
scm *
builtin_p (scm *x)
{
return (x->type == FUNCTION0
|| x->type == FUNCTION1
|| x->type == FUNCTION2
|| x->type == FUNCTION3
|| x->type == FUNCTIONn)
? &scm_t : &scm_f;
}
scm *
boolean_p (scm *x)
{
return (x == &scm_t || x == &scm_f) ? &scm_t : &scm_f;
}
scm *
char_p (scm *x)
{
return x->type == CHAR ? &scm_t : &scm_f;
}
scm *
number_p (scm *x)
{
return x->type == NUMBER ? &scm_t : &scm_f;
}
scm *
string_p (scm *x)
{
return x->type == STRING ? &scm_t : &scm_f;
}
scm *
symbol_p (scm *x)
{
return (x->type == SYMBOL
&& x != &scm_nil
&& x != &scm_f
&& x != &scm_t) ? &scm_t : &scm_f;
}
scm *
vector_p (scm *x)
{
return x->type == VECTOR ? &scm_t : &scm_f;
}
scm *
display (scm *x)
{
return display_helper (x, false, "", false);
}
scm *
call (scm *fn, scm *x)
{
if (fn->type == FUNCTION0)
return fn->function0 ();
if (x->car->type == VALUES)
x = cons (x->car->cdr->car, &scm_nil);
if (fn->type == FUNCTION1)
return fn->function1 (car (x));
if (fn->type == FUNCTION2)
return fn->function2 (car (x), cadr (x));
if (fn->type == FUNCTION3)
return fn->function3 (car (x), cadr (x), caddr (x));
if (fn->type == FUNCTIONn)
return fn->functionn (x);
return &scm_unspecified;
}
scm *
append2 (scm *x, scm *y)
{
if (x == &scm_nil) return y;
assert (x->type == PAIR);
return cons (car (x), append2 (cdr (x), y));
}
scm *
append (scm *x/*...*/)
{
if (x == &scm_nil) return &scm_nil;
return append2 (car (x), append (cdr (x)));
}
scm *
make_char (int x)
{
scm *p = malloc (sizeof (scm));
p->type = CHAR;
p->value = x;
return p;
}
scm *
make_macro (scm *x) //int
{
scm *p = malloc (sizeof (scm));
p->type = MACRO;
p->macro = x;
return p;
}
scm *
make_number (int x)
{
scm *p = malloc (sizeof (scm));
p->type = NUMBER;
p->value = x;
return p;
}
scm *
make_string (char const *s)
{
scm *p = malloc (sizeof (scm));
p->type = STRING;
p->name = strdup (s);
return p;
}
scm *
make_symbol (char const *s)
{
// TODO: alist lookup symbols
scm *p = malloc (sizeof (scm));
p->type = SYMBOL;
p->name = strdup (s);
return p;
}
scm *
make_vector (int n)
{
scm *p = malloc (sizeof (scm));
p->type = VECTOR;
p->length = n;
p->vector = malloc (n * sizeof (scm*));
return p;
}
scm *
string (scm *x/*...*/)
{
char buf[256] = "";
char *p = buf;
while (x != &scm_nil)
{
scm *s = car (x);
assert (s->type == CHAR);
*p++ = s->value;
x = cdr (x);
}
return make_string (buf);
}
scm *
string_append (scm *x/*...*/)
{
char buf[256] = "";
while (x != &scm_nil)
{
scm *s = car (x);
assert (s->type == STRING);
strcat (buf, s->name);
x = cdr (x);
}
return make_string (buf);
}
scm *
string_length (scm *x)
{
assert (x->type == STRING);
return make_number (strlen (x->name));
}
scm *
length (scm *x)
{
int n = 0;
while (x != &scm_nil)
{
n++;
x = cdr (x);
}
return make_number (n);
}
scm *
builtin_list (scm *x/*...*/)
{
return x;
}
scm *
values (scm *x/*...*/)
{
scm *v = cons (0, x);
v->type = VALUES;
return v;
}
scm *
call_with_values_env (scm *producer, scm *consumer, scm *a)
{
scm *v = apply_env (producer, &scm_nil, a);
if (v->type == VALUES)
v = v->cdr;
return apply_env (consumer, v, a);
}
scm *
vector_length (scm *x)
{
assert (x->type == VECTOR);
return make_number (x->length);
}
scm *
vector_ref (scm *x, scm *i)
{
assert (x->type == VECTOR);
assert (i->value < x->length);
return x->vector[i->value];
}
scm *
vector_set_x (scm *x, scm *i, scm *e)
{
assert (x->type == VECTOR);
assert (i->value < x->length);
x->vector[i->value] = e;
return &scm_unspecified;
}
scm *
lookup (char *x, scm *a)
{
if (isdigit (*x) || (*x == '-' && isdigit (*(x+1))))
return make_number (atoi (x));
if (!strcmp (x, scm_dot.name)) return &scm_dot;
if (!strcmp (x, scm_f.name)) return &scm_f;
if (!strcmp (x, scm_nil.name)) return &scm_nil;
if (!strcmp (x, scm_t.name)) return &scm_t;
if (!strcmp (x, scm_unspecified.name)) return &scm_unspecified;
if (!strcmp (x, symbol_begin.name)) return &symbol_begin;
if (!strcmp (x, symbol_closure.name)) return &symbol_closure;
if (!strcmp (x, symbol_cond.name)) return &symbol_cond;
if (!strcmp (x, symbol_current_module.name)) return &symbol_current_module;
if (!strcmp (x, symbol_lambda.name)) return &symbol_lambda;
if (!strcmp (x, symbol_quasiquote.name)) return &symbol_quasiquote;
if (!strcmp (x, symbol_quote.name)) return &symbol_quote;
if (!strcmp (x, symbol_set_x.name)) return &symbol_set_x;
if (!strcmp (x, symbol_unquote.name)) return &symbol_unquote;
if (!strcmp (x, symbol_unquote_splicing.name)) return &symbol_unquote_splicing;
if (!strcmp (x, scm_car.name)) return &scm_car;
if (!strcmp (x, scm_cdr.name)) return &scm_cdr;
if (!strcmp (x, scm_display.name)) return &scm_display;
if (!strcmp (x, scm_builtin_list.name)) return &scm_builtin_list;
if (*x == '\'') return &symbol_quote;
if (*x == '`') return &symbol_quasiquote;
if (*x == ',' && *(x+1) == '@') return &symbol_unquote_splicing;
if (*x == ',') return &symbol_unquote;
return make_symbol (x);
}
scm *
lookup_char (int c, scm *a)
{
char buf[2];
buf[0] = c;
buf[1] = 0;
return lookup (buf, a);
}
char *
list2str (scm *l) // char*
{
static char buf[256];
char *p = buf;
while (l != &scm_nil) {
scm *c = car (l);
assert (c->type == NUMBER);
*p++ = c->value;
l = cdr (l);
}
*p = 0;
return buf;
}
scm*
list_to_vector (scm *x)
{
int n = length (x)->value;
scm *v = make_vector (n);
scm **p = v->vector;
while (x != &scm_nil)
{
*p++ = car (x);
x = cdr (x);
}
return v;
}
scm*
integer_to_char (scm *x)
{
assert (x->type == NUMBER);
return make_char (x->value);
}
scm*
char_to_integer (scm *x)
{
assert (x->type == CHAR);
return make_number (x->value);
}
scm*
number_to_string (scm *x)
{
assert (x->type == NUMBER);
char buf[256];
sprintf (buf,"%d", x->value);
return make_string (buf);
}
scm*
builtin_exit (scm *x)
{
assert (x->type == NUMBER);
exit (x->value);
}
scm*
string_to_symbol (scm *x)
{
assert (x->type == STRING);
return make_symbol (x->name);
}
scm*
symbol_to_string (scm *x)
{
assert (x->type == SYMBOL);
return make_string (x->name);
}
scm*
vector_to_list (scm *v)
{
scm *x = &scm_nil;
for (int i = 0; i < v->length; i++)
x = append2 (x, cons (v->vector[i], &scm_nil));
return x;
}
scm *
newline ()
{
puts ("");
return &scm_unspecified;
}
scm *
display_helper (scm *x, bool cont, char *sep, bool quote)
{
scm *r;
printf ("%s", sep);
if (x->type == CHAR && x->value == 10) printf ("#\\%s", "newline");
else if (x->type == CHAR && x->value == 32) printf ("#\\%s", "space");
else if (x->type == CHAR) printf ("#\\%c", x->value);
else if (x->type == MACRO) {
printf ("(*macro* ");
display_helper (x->macro, cont, sep, quote);
printf (")");
}
else if (x->type == NUMBER) printf ("%d", x->value);
else if (x->type == PAIR) {
if (car (x) == &symbol_circ) {
printf ("(*circ* . #-1#)");
return &scm_unspecified;
}
if (car (x) == &scm_quote) {
printf ("'");
return display_helper (car (cdr (x)), cont, "", true);
}
if (car (x) == &scm_quasiquote) {
printf ("`");
return display_helper (car (cdr (x)), cont, "", true);
}
if (car (x) == &scm_unquote) {
printf (",");
return display_helper (car (cdr (x)), cont, "", true);
}
if (car (x) == &scm_unquote_splicing) {
printf (",@");
return display_helper (car (cdr (x)), cont, "", true);
}
if (!cont) printf ("(");
display (car (x));
if (cdr (x)->type == PAIR)
display_helper (cdr (x), true, " ", false);
else if (cdr (x) != &scm_nil) {
printf (" . ");
display (cdr (x));
}
if (!cont) printf (")");
}
else if (x->type == VECTOR) {
printf ("#(");
for (int i = 0; i < x->length; i++)
display_helper (x->vector[i], true, i ? " " : "", false);
printf (")");
}
else if (atom_p (x) == &scm_t) printf ("%s", x->name);
return &scm_unspecified;
}
// READ
int
ungetchar (int c) //int
{
return ungetc (c, stdin);
}
int
peekchar () //int
{
int c = getchar ();
ungetchar (c);
return c;
}
scm*
builtin_getchar ()
{
return make_number (getchar ());
}
scm*
builtin_peekchar ()
{
return make_number (peekchar ());
}
scm*
builtin_ungetchar (scm *c)
{
assert (c->type == NUMBER);
ungetchar (c->value);
return c;
}
int
readcomment (int c)
{
if (c == '\n') return c;
return readcomment (getchar ());
}
int
readblock (int c)
{
if (c == '!' && peekchar () == '#') return getchar ();
return readblock (getchar ());
}
scm *
readword (int c, char* w, scm *a)
{
if (c == EOF && !w) return &scm_nil;
if (c == '\n' && !w) return readword (getchar (), w, a);
if (c == '\n' && *w == '.' && w[1] == 0) return &scm_dot;
if (c == EOF || c == '\n') return lookup (w, a);
if (c == ' ') return readword ('\n', w, a);
if (c == '"' && !w) return readstring ();
if (c == '"') {ungetchar (c); return lookup (w, a);}
if (c == '(' && !w) return readlist (a);
if (c == '(') {ungetchar (c); return lookup (w, a);}
if (c == ')' && !w) {ungetchar (c); return &scm_nil;}
if (c == ')') {ungetchar (c); return lookup (w, a);}
if (c == ',' && peekchar () == '@') {getchar (); return cons (lookup (",@", a),
cons (readword (getchar (), w, a),
&scm_nil));}
if ((c == '\''
|| c == '`'
|| c == ',')
&& !w) {return cons (lookup_char (c, a),
cons (readword (getchar (), w, a),
&scm_nil));}
if (c == ';') {readcomment (c); return readword ('\n', w, a);}
if (c == '#' && peekchar () == '\\') {getchar (); return readchar ();}
if (c == '#' && !w && peekchar () == '(') {getchar (); return list_to_vector (readlist (a));}
if (c == '#' && peekchar () == '(') {ungetchar (c); return lookup (w, a);}
if (c == '#' && peekchar () == '!') {getchar (); readblock (getchar ()); return readword (getchar (), w, a);}
char buf[256] = {0};
char ch = c;
return readword (getchar (), strncat (w ? w : buf, &ch, 1), a);
}
scm *
readchar ()
{
int c = getchar ();
if (c >= '0' && c <= '7'
&& peekchar () >= '0' && peekchar () <= '7') {
c = c - '0';
while (peekchar () >= '0' && peekchar () <= '7') {
c <<= 3;
c += getchar () - '0';
}
}
else if (c >= 'a' && c <= 'z'
&& peekchar () >= 'a' && peekchar () <= 'z') {
char buf[256];
char *p = buf;
*p++ = c;
while (peekchar () >= 'a' && peekchar () <= 'z') {
*p++ = getchar ();
}
*p = 0;
if (!strcmp (buf, "newline")) c = 10;
else if (!strcmp (buf, "space")) c = 32;
else {
printf ("char not supported: %s", buf);
assert (!"char not supported");
}
}
return make_char (c);
}
scm *
readstring ()
{
char buf[256];
char *p = buf;
int c = getchar ();
while (true) {
if (c == '"') break;
*p++ = c;
if (c == '\\' && peekchar () == '"') *p++ = getchar ();
if (c == EOF) assert (!"EOF in string");
c = getchar ();
}
*p = 0;
return make_string (buf);
}
int
eat_whitespace (int c)
{
while (c == ' ' || c == '\n') c = getchar ();
if (c == ';') return eat_whitespace (readcomment (c));
if (c == '#' && peekchar () == '!') {getchar (); readblock (getchar ()); return eat_whitespace (getchar ());}
return c;
}
scm *
readlist (scm *a)
{
int c = getchar ();
c = eat_whitespace (c);
if (c == ')') return &scm_nil;
scm *w = readword (c, 0, a);
if (w == &scm_dot)
return car (readlist (a));
return cons (w, readlist (a));
}
scm *
readenv (scm *a)
{
return readword (getchar (), 0, a);
}
scm *
greater_p (scm *a, scm *b)
{
assert (a->type == NUMBER);
assert (b->type == NUMBER);
return a->value > b->value ? &scm_t : &scm_f;
}
scm *
less_p (scm *a, scm *b)
{
assert (a->type == NUMBER);
assert (b->type == NUMBER);
return a->value < b->value ? &scm_t : &scm_f;
}
scm *
minus (scm *x/*...*/)
{
scm *a = car (x);
assert (a->type == NUMBER);
int n = a->value;
x = cdr (x);
if (x == &scm_nil)
n = -n;
while (x != &scm_nil)
{
assert (x->car->type == NUMBER);
n -= x->car->value;
x = cdr (x);
}
return make_number (n);
}
scm *
plus (scm *x/*...*/)
{
int n = 0;
while (x != &scm_nil)
{
assert (x->car->type == NUMBER);
n += x->car->value;
x = cdr (x);
}
return make_number (n);
}
scm *
divide (scm *x/*...*/)
{
int n = 1;
if (x != &scm_nil) {
assert (x->car->type == NUMBER);
n = x->car->value;
x = cdr (x);
}
while (x != &scm_nil)
{
assert (x->car->type == NUMBER);
n /= x->car->value;
x = cdr (x);
}
return make_number (n);
}
scm *
multiply (scm *x/*...*/)
{
int n = 1;
while (x != &scm_nil)
{
assert (x->car->type == NUMBER);
n *= x->car->value;
x = cdr (x);
}
return make_number (n);
}
scm *
is_p (scm *a, scm *b)
{
assert (a->type == NUMBER);
assert (b->type == NUMBER);
return a->value == b->value ? &scm_t : &scm_f;
}
scm *add_environment (scm *a, char *name, scm *x);
scm *
add_unquoters (scm *a)
{
a = add_environment (a, "unquote", &scm_unquote);
a = add_environment (a, "unquote-splicing", &scm_unquote_splicing);
return a;
}
scm *
add_environment (scm *a, char *name, scm *x)
{
return cons (cons (make_symbol (name), x), a);
}
scm *
mes_environment ()
{
scm *a = &scm_nil;
a = cons (cons (&scm_f, &scm_f), a);
a = cons (cons (&scm_nil, &scm_nil), a);
a = cons (cons (&scm_t, &scm_t), a);
a = cons (cons (&scm_unspecified, &scm_unspecified), a);
#include "environment.i"
return a;
}
scm *
make_lambda (scm *args, scm *body)
{
return cons (&symbol_lambda, cons (args, body));
}
scm *
make_closure (scm *args, scm *body, scm *a)
{
return cons (&symbol_closure, cons (cons (&symbol_circ, cdr (a)), cons (args, body)));
}
scm *
def (scm *x)
{
if (atom_p (cadr (x)) != &scm_f)
return cons (cadr (x), x);
return cons (caadr (x), x);
}
scm *
define (scm *x, scm *a)
{
scm *e;
scm *name = cadr (x);
if (name->type != PAIR)
e = eval (caddr (x), cons (cons (cadr (x), cadr (x)), a));
else {
name = car (name);
scm *p = pairlis (cadr (x), cadr (x), a);
e = eval (make_lambda (cdadr (x), cddr (x)), p);
}
if (eq_p (car (x), &symbol_define_macro) == &scm_t)
e = make_macro (e);
return cons (name, e);
}
scm *
lookup_macro (scm *x, scm *a)
{
scm *m = assq (x, a);
if (m != &scm_f && macro_p (cdr (m)) != &scm_f)
return cdr (m)->macro;
return &scm_f;
}
scm *
read_file (scm *e, scm *a)
{
if (e == &scm_nil) return e;
return cons (e, read_file (readenv (a), a));
}
int
main (int argc, char *argv[])
{
scm *a = mes_environment ();
display (eval (cons (&symbol_begin, read_file (readenv (a), a)), a));
newline ();
return 0;
}
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