c/env.c

   1 /*
   2 #include <stdarg.h>
   3 #include <stdio.h>
   4 #include <string.h>
   5 */
   6 #include <stdlib.h>
   7 #include "types.h"
   8
   9 // Env
  10
  11 Env *new_env(Env *outer, MalVal* binds, MalVal *exprs) {
  12     Env *e = malloc(sizeof(Env));
  13     e->table = g_hash_table_new(g_str_hash, g_str_equal);
  14     e->outer = outer;
  15
  16     if (binds && exprs) {
  17         assert_type(binds, MAL_LIST|MAL_VECTOR,
  18                     "new_env called with non-sequential bindings");
  19         assert_type(exprs, MAL_LIST|MAL_VECTOR,
  20                     "new_env called with non-sequential expressions");
  21         int binds_len = _count(binds),
  22             exprs_len = _count(exprs),
  23             varargs = 0, i;
  24         for (i=0; i<binds_len; i++) {
  25             if (i > exprs_len) { break; }
  26             if (_nth(binds, i)->val.string[0] == '&') {
  27                 varargs = 1;
  28                 env_set(e, _nth(binds, i+1)->val.string, _slice(exprs, i, _count(exprs)));
  29                 break;
  30             } else {
  31               env_set(e, _nth(binds, i)->val.string, _nth(exprs, i));
  32             }
  33         }
  34         assert(varargs || (binds_len == exprs_len),
  35                "Arity mismatch: %d formal params vs %d actual params",
  36                binds_len, exprs_len);
  37
  38     }
  39     return e;
  40 }
  41
  42 Env *env_find(Env *env, char *key) {
  43     void *val = g_hash_table_lookup(env->table, key);
  44     if (val) {
  45         return env;
  46     } else if (env->outer) {
  47         return env_find(env->outer, key);
  48     } else {
  49         return NULL;
  50     }
  51 }
  52
  53 MalVal *env_get(Env *env, char *key) {
  54     Env *e = env_find(env, key);
  55     assert(e, "'%s' not found", key);
  56     return g_hash_table_lookup(e->table, key);
  57 }
  58
  59 Env *env_set(Env *env, char *key, MalVal *val) {
  60     g_hash_table_insert(env->table, key, val);
  61     return env;
  62 }