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/* lith: interpreter */
#include "lith.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
static void show_version(void)
{
fprintf(stderr,
"lith version %s: a small lisp-like language interpreter\n",
LITH_VERSION_STRING);
}
static void show_help(char *progname)
{
show_version();
fprintf(stderr,
"usage: \n"
" %s [-h | --help] [-v | --version] [-i | --interactive]\n"
" %s [(-e | --evaluate) expr ...]\n"
" %s [--] FILE [ARGS] ...\n\n",
progname, progname, progname);
fprintf(stderr,
"Available options: \n\n"
" -e expr ...\n"
" --evaluate expr ...\n"
" evaluate the expression(s)\n\n"
" -h, --help\n"
" show this help\n\n"
" -i, --interactive\n"
" run an interactive session (REPL)\n\n"
" -v, --version\n"
" show version\n\n"
"");
}
static lith_value *get_list_of_arguments(lith_st *L, char **arg)
{
lith_value *arguments, *cur, *str;
arguments = cur = L->nil;
if (!cur)
return NULL;
for (; *arg; arg++) {
str = lith_make_string(L, *arg, strlen(*arg));
if (!str || LITH_IS_ERR(L)) {
lith_free_value(arguments);
return NULL;
}
if (LITH_IS_NIL(cur)) {
arguments = LITH_CONS(L, str, L->nil);
cur = arguments;
} else {
LITH_CDR(cur) = LITH_CONS(L, str, L->nil);
cur = LITH_CDR(cur);
}
}
return arguments;
}
static char *read_line(int *line_empty)
{
size_t length = 0, capacity = 0;
int c;
char *start = NULL, *cur = NULL, *tmp;
while (((c = getchar()) != EOF) && (c != '\n')) {
if ((length + 1) >= capacity) {
tmp = realloc(start, capacity += BUFSIZ);
if (!tmp) {
free(start);
return NULL;
}
start = tmp;
cur = start + length;
}
*cur++ = c;
++length;
}
if (cur) *cur = 0;
*line_empty = !start && (c == '\n');
return start;
}
int main(int argc, char **argv)
{
int ret, empty_line;
size_t len;
lith_st T, *L;
lith_env *V;
lith_value *arguments;
char **args, *opt, **expr, *filename, *line;
enum { LITH__REPL, LITH__EXPR, LITH__RUN_FILE } state;
if (argc < 2) {
show_help(argv[0]);
return 2;
}
opt = argv[1];
#define OPT(short_form, long_form) \
((strcmp(opt, short_form) == 0) \
|| (strcmp(opt, long_form) == 0))
if (opt[0] == '-') {
if (OPT("-v", "--version")) {
show_version();
return 0;
} else if (OPT("-h", "--help")) {
show_help(argv[0]);
return 0;
} else if (OPT("-i", "--interactive")) {
state = LITH__REPL;
} else if (OPT("-e", "--evaluate")) {
state = LITH__EXPR;
if (!argv[2]) {
fprintf(stderr,
"lith: expecting at least one argument for '%s'\n", argv[1]);
return 3;
}
expr = argv+2;
} else if (!strcmp(opt, "--")) {
if (!argv[2]) {
fprintf(stderr, "lith: expecting filename after '--'\n");
return 4;
}
state = LITH__RUN_FILE;
filename = argv[2];
args = argv+3;
} else {
fprintf(stderr,
"lith: invalid option '%s': "
"try '%s --help' for available options\n",
argv[1], argv[0]);
return 5;
}
} else {
state = LITH__RUN_FILE;
filename = argv[1];
args = argv+2;
}
#undef OPT
L = &T;
lith_init(L);
V = lith_new_env(L, L->global);
lith_run_file(L, L->global, "lib.lith");
if (LITH_IS_ERR(L))
return 6;
switch (state) {
case LITH__EXPR:
for (; *expr; expr++) {
lith_run_string(L, V, *expr, 0);
if (LITH_IS_ERR(L)) {
ret |= 8;
break;
}
}
break;
case LITH__RUN_FILE:
arguments = get_list_of_arguments(L, args);
if (!arguments) {
ret |= 16;
break;
}
lith_env_put(L, V, lith_get_symbol(L, "arguments"), arguments);
lith_run_file(L, V, filename);
break;
case LITH__REPL:
show_version();
for (;;) {
printf("lith> ");
line = read_line(&empty_line);
if (empty_line) continue;
if (!line) {
printf("\nBye!\n");
break;
}
lith_run_string(L, V, line, 1);
free(line);
if (LITH_IS_ERR(L))
lith_clear_error_state(L);
}
break;
}
lith_free_env(V);
lith_free(L);
return ret;
}
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