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add parent environments

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This commit is contained in:
NunoSempere 2023-05-07 12:49:09 -04:00
parent c16f08f22a
commit 1dfba9f4a1
1 changed files with 21 additions and 6 deletions
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27
src/mumble.c
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@ -286,15 +286,17 @@ struct lispenv {
int count;
char** syms; // list of strings
lispval** vals; // list of pointers to vals
lispenv* parent;
};
lispenv* new_lispenv()
{
lispenv* n = malloc(sizeof(lispenv));
n->count = 0;
n->syms = NULL;
n->vals = NULL;
return n;
lispenv* e = malloc(sizeof(lispenv));
e->count = 0;
e->syms = NULL;
e->vals = NULL;
e->parent = NULL;
return e;
}
void destroy_lispenv(lispenv* env)
@ -311,8 +313,12 @@ void destroy_lispenv(lispenv* env)
env->vals = NULL;
free(env);
env = NULL;
// parent is it's own environment
// so it isn't destroyed
}
lispval* clone_lispval(lispval* old);
lispval* get_from_lispenv(char* sym, lispenv* env)
{
@ -322,7 +328,13 @@ lispval* get_from_lispenv(char* sym, lispenv* env)
// return env->vals[i];
}
}
return lispval_err("Error: unbound symbol");
if(env->parent != NULL){
return get_from_lispenv(sym, env->parent);
} else {
return lispval_err("Error: unbound symbol");
}
// and this explains shadowing!
}
void insert_in_lispenv(char* sym, lispval* v, lispenv* env)
@ -739,6 +751,9 @@ lispval* builtin_def(lispval* v, lispenv* env)
// A builtin for defining a function
lispval* builtin_define_lambda(lispval* v, lispenv* env){
// @ { {x y} { + x y } }
// def { {plus} {{@ {x y} {+ x y}} }}
// (eval plus) 1 2
// (@ { {x y} { + x y } }) 1 2
LISPVAL_ASSERT( v->count == 2, "Lambda definition requires two arguments; try @ { {x y} { + x y } }");
LISPVAL_ASSERT(v->cell[0]->type == LISPVAL_QEXPR, "Lambda definition (@) requires that the first sub-arg be a q-expression; try @ { {x y} { + x y } }");
LISPVAL_ASSERT(v->cell[1]->type == LISPVAL_QEXPR, "Lambda definition (@) requires that the second sub-arg be a q-expression; try @ { {x y} { + x y } }");