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Added variable length lambda functions

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This commit is contained in:
Brandon Rozek 2018-06-10 12:22:20 -04:00
parent e6924523cf
commit f592d69179
1 changed files with 36 additions and 0 deletions
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36
lval/environment.c
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@ -235,6 +235,21 @@ lval* lval_call(lenv* e, lval* f, lval* a) {
// Pop the first symbol from the formals
lval* sym = lval_pop(f->formals, 0);
if (strcmp(sym->sym, "&") == 0) {
// Ensure '&' is followed by another symbol
if (f->formals->count != 1) {
lval_del(a);
return lval_err("Function format invalid."
"Symbol '&' not followed by single symbol.");
}
// Next formal should be bounded to remaining arguments
lval* nsym = lval_pop(f->formals, 0);
lenv_put(f->env, nsym, builtin_list(e, a));
lval_del(sym); lval_del(nsym);
break;
}
// Pop the next argument from the list
lval* val = lval_pop(a, 0);
@ -248,6 +263,27 @@ lval* lval_call(lenv* e, lval* f, lval* a) {
// The argument list is now bounded so we can clean up the given
lval_del(a);
// If '&' remains in formal list bind to empty list
if (f->formals->count > 0 &&
strcmp(f->formals->cell[0]->sym, "&") == 0) {
// Check to ensure that & is no passed invalidly
if (f->formals->count != 2) {
return lval_err("Function format invalid."
"Symbol '&' not followed by single symbol.");
}
// Pop and delete '&' symbol
lval_del(lval_pop(f->formals, 0));
// Pop next symbol and create empty list
lval* sym = lval_pop(f->formals, 0);
lval* val = lval_qexpr();
// Bind to environment and delete
lenv_put(f->env, sym, val);
lval_del(sym); lval_del(val);
}
// If all formals have been bounded evaluate
if (f->formals->count == 0) {
// Set environment parent to evaluation environment