// To delete the WHOLE linked list, given its head.
void ll_delete_all(ll_cnode*& head)
{
if (head == NULL) // An empty list; nothing to delete
return;
ll_delete_all(head->next); // STEP 1: First delete the remaining nodes
// For debugging: this shows you what are deleting
cout << "deleting " << head->data << endl;
delete head; // STEP 2: Then delete the current nodes
head = NULL; // STEP 3: To play safe, reset head to NULL
}
static statement *get_expression(parse_source *source, int *indent) {
parse_token token = get_mandatory_token(source);
if(equals_string(token.data, "{")) {
statement *expression = new(expression);
expression->type = BLOCK;
expression->children = ll_new();
expression->data = new_slice("");
int finished = *indent;
*indent += 1;
while(*indent != finished) {
statement *state = get_expression(source, indent);
if(state != NULL)
ll_add_last(expression->children, state);
}
return expression;
} else if(equals_string(token.data, "}")) {
*indent -= 1;
return NULL;
} else if(equals_string(token.data, "if") || equals_string(token.data, "while") || equals_string(token.data, "for")) {
statement *expression = new(expression);
if(equals_string(token.data, "if"))
expression->type = IF;
else if(equals_string(token.data, "while"))
expression->type = WHILE;
else if(equals_string(token.data, "for"))
expression->type = FOR;
expression->children = ll_new();
expression->data = new_slice("");
ll_add_last(expression->children, get_expression(source, indent)); //Add the header
if(expression->type == FOR) {
ll_add_last(expression->children, get_expression(source, indent)); //Add the header
ll_add_last(expression->children, get_expression(source, indent)); //Add the header
}
ll_add_last(expression->children, get_expression(source, indent)); //Add the body
if(expression->type == IF) {
parse_token next = peek_mandatory_token(source);
if(equals_string(next.data, "else")) {
get_mandatory_token(source);
statement *elseState = new(elseState);
elseState->type = ELSE;
elseState->children = ll_new();
elseState->data = new_slice("");
ll_add_last(expression->children, elseState);
ll_add_first(elseState->children, get_expression(source, indent));
}
}
return expression;
} else if(equals_string(token.data, "break") || equals_string(token.data, "continue")) {
statement *expression = new(expression);
expression->type = equals_string(token.data, "break") ? BREAK : CONTINUE;
expression->data = new_slice("");
expression->children = NULL;
parse_token next = get_mandatory_token(source);
if(!equals_string(next.data, ";"))
semantic_error("Expected a semicolon after a break or continue", next.origin);
return expression;
} else if(equals_string(token.data, "return")) {
statement *expression = new(expression);
expression->type = RETURN;
expression->data = new_slice("");
expression->children = ll_new();
ll_add_last(expression->children, get_expression(source, indent));
return expression;
} else {
linked_list *accumulator = ll_new();
parse_token next = token;
while(true) {
parse_token *allocated = new(allocated);
*allocated = token;
ll_add_last(accumulator, allocated);
next = peek_mandatory_token(source);
if(equals_string(next.data, "{") || equals_string(next.data, "}"))
break;
if(equals_string(next.data, ";")) {
get_mandatory_token(source);
break;
}
token = get_mandatory_token(source);
}
statement *expression = parse_simple_expression(accumulator);
ll_delete_all(accumulator);
return expression;
}
}
