124 lines
No EOL
3.5 KiB
C
124 lines
No EOL
3.5 KiB
C
#include "environment.h"
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#include <stdlib.h>
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#include "error.h"
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#include "expressions.h"
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#include "operations.h"
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lenv* lenv_new(void) {
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lenv* e = (lenv*) malloc(sizeof(lenv));
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e->count = 0;
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e->syms = NULL;
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e->vals = NULL;
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return e;
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}
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void lenv_del(lenv* e) {
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for (int i = 0; i < e->count; i++) {
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free(e->syms[i]);
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lval_del(e->vals[i]);
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}
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free(e->syms);
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free(e->vals);
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free(e);
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}
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lval* lenv_get(lenv* e, lval* k) {
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// Iterate over all items in environment
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for (int i = 0; i < e->count; i++) {
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// Check if the stored string matches the symbol string
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// If it does, return a copy of hte value
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if (strcmp(e->syms[i], k->sym) == 0) {
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return lval_copy(e->vals[i]);
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}
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}
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// If no symbol found return error
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return lval_err("unbounded symbol!");
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}
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void lenv_put(lenv* e, lval* k, lval* v) {
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// Iterate over all items in the environment
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// This is to see if the variables already exist
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for (int i = 0; i < e->count; i++) {
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// If a variable is found, delete the item at that position
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// Then replace it with the data provided by the user
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if (strcmp(e->syms[i], k->sym) == 0) {
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lval_del(e->vals[i]);
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e->vals[i] = lval_copy(v);
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return;
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}
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}
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// If no existing entry is found, allocate space for new entry
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e->count++;
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e->vals = realloc(e->vals, sizeof(lval*) * e->count);
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e->syms = realloc(e->syms, sizeof(char*) * e->count);
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// Copy contents of lval and symbol string
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e->vals[e->count - 1] = lval_copy(v);
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e->syms[e->count - 1] = (char*) malloc(strlen(k->sym) + 1);
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strcpy(e->syms[e->count - 1], k->sym);
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}
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lval* lval_fun(lbuiltin func) {
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lval* v = malloc(sizeof(lval));
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v->type = LVAL_FUN;
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v->fun = func;
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return v;
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}
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void lenv_add_builtin(lenv* e, char* name, lbuiltin func) {
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lval* k = lval_sym(name);
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lval* v = lval_fun(func);
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lenv_put(e, k, v);
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lval_del(k); lval_del(v);
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}
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void lenv_add_builtins(lenv* e) {
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// List functions
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lenv_add_builtin(e, "list", builtin_list);
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lenv_add_builtin(e, "head", builtin_head);
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lenv_add_builtin(e, "tail", builtin_tail);
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lenv_add_builtin(e, "eval", builtin_eval);
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lenv_add_builtin(e, "join", builtin_join);
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lenv_add_builtin(e, "len", builtin_len);
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lenv_add_builtin(e, "cons", builtin_cons);
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// Mathematical Functions
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lenv_add_builtin(e, "+", builtin_add);
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lenv_add_builtin(e, "-", builtin_sub);
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lenv_add_builtin(e, "*", builtin_mul);
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lenv_add_builtin(e, "/", builtin_div);
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lenv_add_builtin(e, "^", builtin_pow);
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lenv_add_builtin(e, "%", builtin_mod);
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lenv_add_builtin(e, "min", builtin_min);
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lenv_add_builtin(e, "max", builtin_max);
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lenv_add_builtin(e, "def", builtin_def);
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}
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lval* builtin_def(lenv* e, lval* a) {
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LASSERT(a, a->cell[0]->type == LVAL_QEXPR,
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"Function 'def' passed incorrect type")
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// First argument is the symbol list
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lval* syms = a->cell[0];
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// Ensure all elements of the first list are symbols
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for (int i = 0; i < syms->count; i++) {
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LASSERT(a, syms->cell[i]->type == LVAL_SYM,
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"Function 'def' cannot define non-symbol")
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}
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// Check correct number of symbols and values
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LASSERT(a, syms->count == a->count - 1,
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"Function 'def' cannot define incorrect number of values to symbols")
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// Assign copies of values to symbols
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for (int i = 0; i < syms->count; i++) {
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lenv_put(e, syms->cell[i], a->cell[i + 1]);
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}
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lval_del(a);
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return lval_sexpr();
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} |