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#include <stdio.h>
#include <stdlib.h>
#include <readline/readline.h>
#include <readline/history.h>
#include "lisp.h"
#include "lex.yy.h"
#include "lisp.tab.h"
env *global_env = NULL;
void eval_file(const char *filename) {
FILE *f = fopen(filename, "r");
if (!f) {
fprintf(stderr, "could not open file: %s\n", filename);
return;
}
int parens = 0;
char line[1024];
char buffer[4096] = "";
while (fgets(line, sizeof(line), f)) {
if (*line == '\n' || *line == ';') continue; // skip empty lines or comments
for (char *c = line; *c != '\0'; c++) {
if (*c == '(') {
parens++;
} else if (*c == ')') {
parens--;
}
}
//append line to buffer
strcat(buffer, line);
strcat(buffer, "\n");
if (parens <= 0) {
//if parens are balanced: parse
yy_scan_string(buffer);
yyparse();
//reset buffer
buffer[0] = '\0';
}
}
fclose(f);
}
char *env_token_gen(const char *text, int state) {
static int len;
static env *nth_env;
if (state == 0) {
nth_env = global_env->next;
len = strlen(text);
}
while (nth_env) {
const char *cur = nth_env->symbol;
nth_env = nth_env->next;
if (strncmp(cur, text, len) == 0) {
return strdup(cur);
}
}
return NULL;
}
/* Dispatch function: called by readline to get all matches */
char **my_completion(const char *text, int start, int end) {
/* Prevent default filename completion */
rl_attempted_completion_over = 1;
return rl_completion_matches(text, env_token_gen);
}
void init_readline() {
rl_attempted_completion_function = my_completion;
}
int main(int argc, char **argv) {
// init global env
global_env = env_create(NULL);
env_define(global_env, "cons", make_builtin(builtin_cons));
env_define(global_env, "car", make_builtin(builtin_car));
env_define(global_env, "cdr", make_builtin(builtin_cdr));
env_define(global_env, "reverse", make_builtin(builtin_reverse));
env_define(global_env, "null?", make_builtin(builtin_isnull));
env_define(global_env, "eq?", make_builtin(builtin_eq));
env_define(global_env, "+", make_builtin(builtin_add));
env_define(global_env, "-", make_builtin(builtin_sub));
env_define(global_env, "*", make_builtin(builtin_mul));
env_define(global_env, "/", make_builtin(builtin_div));
env_define(global_env, "<", make_builtin(builtin_lt));
// evaluate files
for(int i = 1; i < argc; i++) {
eval_file(argv[i]);
}
// START REPL
init_readline();
int parens = 0;
char *line;
char buffer[4096] = "";
char *prompt = "λ> ";
while ((line = readline(prompt)) != NULL) {
for (char *c = line; *c != '\0'; c++) {
if (*c == '(') {
parens++;
} else if (*c == ')') {
parens--;
}
}
//append line to buffer
strcat(buffer, line);
if (parens <= 0) {
//if parens are balanced parse
yy_scan_string(buffer);
yyparse();
add_history(buffer);
//reset buffer and prompt string
buffer[0] = '\0';
prompt = "λ> ";
} else {
strcat(buffer, "\n");
prompt = " ";
}
free(line);
}
return 0;
}
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