+### Function calls
+
+A function call can appear either as an expression or as a statement.
+As functions cannot yet return values, only the statement version will work.
+We use a new 'Funcall' binode type to link the function with a list of
+arguments, form with the 'List' nodes.
+
+###### Binode types
+ Funcall,
+
+###### expression grammar
+ | Variable ( ExpressionList ) ${ {
+ struct binode *b = new(binode);
+ b->op = Funcall;
+ b->left = $<V;
+ b->right = reorder_bilist($<EL);
+ $0 = b;
+ } }$
+ | Variable ( ) ${ {
+ struct binode *b = new(binode);
+ b->op = Funcall;
+ b->left = $<V;
+ b->right = NULL;
+ $0 = b;
+ } }$
+
+###### SimpleStatement Grammar
+
+ | Variable ( ExpressionList ) ${ {
+ struct binode *b = new(binode);
+ b->op = Funcall;
+ b->left = $<V;
+ b->right = reorder_bilist($<EL);
+ $0 = b;
+ } }$
+
+###### print binode cases
+
+ case Funcall:
+ do_indent(indent, "");
+ print_exec(b->left, -1, bracket);
+ printf("(");
+ for (b = cast(binode, b->right); b; b = cast(binode, b->right)) {
+ if (b->left) {
+ printf(" ");
+ print_exec(b->left, -1, bracket);
+ if (b->right)
+ printf(",");
+ }
+ }
+ printf(")");
+ if (indent >= 0)
+ printf("\n");
+ break;
+
+###### propagate binode cases
+
+ case Funcall: {
+ /* Every arg must match formal parameter, and result
+ * is return type of function (currently Tnone).
+ */
+ struct binode *args = cast(binode, b->right);
+ struct var *v = cast(var, b->left);
+
+ if (!v->var->type || v->var->type->check_args == NULL) {
+ type_err(c, "error: attempt to call a non-function.",
+ prog, NULL, 0, NULL);
+ return NULL;
+ }
+ v->var->type->check_args(c, ok, v->var->type, args);
+ return Tnone;
+ }
+
+###### interp binode cases
+
+ case Funcall: {
+ struct var *v = cast(var, b->left);
+ struct type *t = v->var->type;
+ void *oldlocal = c->local;
+ int old_size = c->local_size;
+ void *local = calloc(1, t->function.local_size);
+ struct value *fbody = var_value(c, v->var);
+ struct binode *arg = cast(binode, b->right);
+ struct binode *param = t->function.params;
+
+ while (param) {
+ struct var *pv = cast(var, param->left);
+ struct type *vtype = NULL;
+ struct value val = interp_exec(c, arg->left, &vtype);
+ struct value *lval;
+ c->local = local; c->local_size = t->function.local_size;
+ lval = var_value(c, pv->var);
+ c->local = oldlocal; c->local_size = old_size;
+ memcpy(lval, &val, vtype->size);
+ param = cast(binode, param->right);
+ arg = cast(binode, arg->right);
+ }
+ c->local = local; c->local_size = t->function.local_size;
+ right = interp_exec(c, fbody->function, &rtype);
+ c->local = oldlocal; c->local_size = old_size;
+ free(local);
+ break;
+ }
+
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