cosmopolitan/tool/lambda/lambda.c

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2022-03-17 21:12:41 +00:00
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi
Copyright 2022 Justine Alexandra Roberts Tunney
Permission to use, copy, modify, and/or distribute this software for
any purpose with or without fee is hereby granted, provided that the
above copyright notice and this permission notice appear in all copies.
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THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
PERFORMANCE OF THIS SOFTWARE.
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*/
#include "libc/assert.h"
#include "libc/calls/calls.h"
#include "libc/calls/struct/rlimit.h"
#include "libc/calls/struct/sigaction.h"
#include "libc/log/log.h"
#include "libc/runtime/runtime.h"
#include "libc/stdio/stdio.h"
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#include "libc/str/locale.h"
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#include "libc/sysv/consts/map.h"
#include "libc/sysv/consts/prot.h"
#include "libc/sysv/consts/rlimit.h"
#include "libc/sysv/consts/sig.h"
#include "third_party/getopt/getopt.internal.h"
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#include "tool/lambda/lib/blc.h"
#define USAGE \
" [-?hubBdsarvnNlS] <stdin >expr.txt\n\
Binary Lambda Calculus Virtual Machine\n\
\n\
FLAGS\n\
\n\
-h help\n\
-r rex log\n\
-b binary 8-bit i/o\n\
-B debug print binary\n\
-l print lambda notation\n\
-a action log [implies -r]\n\
-v variable log [implies -r]\n\
-s full machine state logging\n\
-n disables name rewriting rules\n\
-N disables most unicode symbolism\n\
-d dump terms on successful exit\n"
#define NIL 23
#define TRUE 27
#define FALSE 23
#define REF(c) (++(c)->refs, c)
static const char kRom[] = {
APP, 0, // 0 (λ 0 λ 0 (λ 0 wr0 wr1) put) (main gro)
ABS, // 2 λ 0 λ 0 (λ 0 wr0 wr1) put
APP, 0, // 3
VAR, 0, // 5
ABS, // 7
APP, // 8
ABS, // 9 λ 0 λ 0 wr0 wr1
APP, 2, // 10
VAR, // 12
IOP, // 13
ABS, // 14 λ 0 wr0 wr1
APP, 4, // 15
APP, 1, // 17
VAR, // 19
IOP, // 20 wr0
IOP, 0, // 21 wr1
ABS, // 23 (λλ 0) a.k.a. nil
ABS, // 24 exit
VAR, // 25
0, // 26 exit[0]
ABS, // 27 (λλ 1) a.k.a. true
ABS, // 28
VAR, 1, // 29
};
static int postdump;
static int kLazy[256];
void Quit(int sig) {
Dump(0, end, stderr);
exit(128 + sig);
}
void PrintUsage(const char *prog, int rc, FILE *f) {
fputs("Usage: ", f);
fputs(prog, f);
fputs(USAGE, f);
exit(rc);
}
int Backref(int x) {
return x - (end + 1);
}
static inline void Expand(int c) {
if (end >= TERMS) Error(5, "OUT OF TERMS");
mem[end++] = c;
}
void Gc(struct Closure *p) {
struct Closure *t;
while (p && p != &root) {
if (--p->refs) break;
Gc(p->next);
t = p->envp;
p->envp = 0;
p->next = frep;
frep = p;
p = t;
}
}
void Var(void) {
int i, x;
struct Closure *t, *e;
e = t = envp;
x = mem[ip + 1];
for (i = 0; i < x && e != &root; ++i) e = e->next;
if (e == &root) Error(10 + x, "UNDEFINED VARIABLE %d", x);
ip = e->term;
envp = REF(e->envp);
Gc(t);
}
void Gro(void) {
int c = fgetc(stdin);
if (c != -1) {
Expand(ABS);
Expand(APP);
Expand(4);
Expand(APP);
Expand(Backref(binary ? kLazy[c] : c & 1 ? FALSE : TRUE));
Expand(VAR);
Expand(0);
} else {
Expand(ABS);
Expand(ABS);
Expand(VAR);
Expand(0);
}
}
void Put(void) {
int bit;
long newip;
if (!binary) {
co = '0' + (ip & 1);
fputc(co, stdout);
newip = 2;
} else if (mem[ip + 1] & 1) { // ip ∈ {6,13}
fputc(co, stdout);
newip = 2;
} else { // ip ∈ {20,21}
newip = 9; // (λ 0 (λ 0 wr1 wr0))
bit = ip & 1;
co = (co * 2) | bit;
}
if (ferror(stdout)) {
exit(55);
}
ip = newip;
}
void Bye(void) {
int rc = mem[ip + 2]; // (λ 0) [exitcode]
if (rc) Error(rc, "CONTINUATIONS EXHAUSTED");
if (postdump && !rc) Dump(0, end, stderr);
exit(0);
}
// pops continuation and pushes it to environment
void Abs(void) {
if (!contp) Bye();
struct Closure *t = contp;
contp = t->next;
t->next = envp;
envp = t;
++ip;
}
struct Closure *Alloc(void) {
struct Closure *t;
if (!(t = frep)) {
if (!(t = Calloc(1, sizeof(struct Closure)))) {
Error(6, "OUT OF HEAP");
}
}
frep = t->next;
t->refs = 1;
++heap;
return t;
}
// pushes continuation for argument
void App(void) {
int x = mem[ip + 1];
struct Closure *t = Alloc();
t->term = ip + 2 + x;
t->envp = t->term > 21 && t->term != end ? REF(envp) : &root;
t->next = contp;
contp = t;
ip += 2;
}
int LoadByte(int c) {
int i, r = end;
for (i = 7; i >= 0; --i) {
Expand(ABS);
Expand(APP);
Expand(i ? +4 : Backref(NIL));
Expand(APP);
Expand(Backref(c & (1 << i) ? FALSE : TRUE));
Expand(VAR);
Expand(0);
}
return r;
}
void LoadRom(void) {
long i;
for (; end < sizeof(kRom) / sizeof(*kRom); ++end) {
mem[end] = kRom[end];
}
mem[4] = binary ? 2 : 9;
if (binary) {
for (i = 0; i < 256; ++i) {
kLazy[i] = LoadByte(i);
}
}
mem[1] = end - 2;
}
void Iop(void) {
if (ip == end) {
Gro();
} else {
Put(); // ip ∈ {6,13,20,21}
}
Gc(envp);
envp = &root;
}
static void Rex(void) {
if (slog) PrintMachineState(stderr);
if (rlog && (alog || mem[ip] != APP)) {
PrintExpressions(stderr, alog, vlog);
}
switch (mem[ip]) {
case VAR:
Var();
break;
case APP:
App();
break;
case ABS:
Abs();
break;
case IOP:
Iop();
break;
default:
Error(7, "CORRUPT TERM");
}
}
void Krivine(void) {
int main;
long gotoget;
LoadRom();
mem[end++] = APP;
gotoget = end++;
main = end;
mem[gotoget] = Parse(1, stdin).n;
if (rlog) {
Print(main, 1, 0, stderr);
fputs("\n", stderr);
if (alog) {
fputs("⟿ wrap[", stderr);
Print(0, 1, 0, stderr);
fputs("]\n", stderr);
}
}
for (;;) Rex();
}
void LoadFlags(int argc, char *argv[]) {
int i;
const char *prog;
prog = argc ? argv[0] : "cblc";
while ((i = getopt(argc, argv, "?hubBdsarvnNlS")) != -1) {
switch (i) {
case 'b':
binary = 1;
break;
case 'S':
safer = 1;
break;
case 'n':
noname = 1;
break;
case 'N':
asciiname = 1;
break;
case 'B':
style = 2;
break;
case 'l':
style = 1;
break;
case 's':
slog = 1;
break;
case 'r':
rlog = 1;
break;
case 'a':
rlog = 1;
alog = 1;
break;
case 'v':
rlog = 1;
vlog = 1;
break;
case 'd':
postdump = 1;
break;
case '?':
case 'h':
PrintUsage(prog, 0, stdout);
default:
PrintUsage(prog, 1, stderr);
}
}
}
int main(int argc, char *argv[]) {
struct rlimit rlim = {512 * 1024 * 1024, 512 * 1024 * 1024};
setrlimit(RLIMIT_AS, &rlim);
signal(SIGQUIT, Quit);
signal(SIGPIPE, Quit);
LoadFlags(argc, argv);
setlocale(LC_ALL, "");
setvbuf(stdout, 0, _IOLBF, 0);
setvbuf(stderr, 0, _IOLBF, 0);
Krivine();
}