SIG11 crashing - can't figure it out

[John Colvin via Digitalmars-d-learn]

On Friday, 15 May 2015 at 11:08:06 UTC, Rob Pieké wrote:
> Working my way through Ali Çehreli's rather amazing e-book, 
> I've hit a snag where some code I've written is pretty crashy. 
> I consistently get "Segmentation fault: 11" (dmd 2.067.1, OSX).
>
> I can't figure out where things are going wrong, because any 
> attempt I make to debug via extra print statements causes the 
> program to run successfully. Same if I try to compile with 
> "-gc" ... it suddenly starts working, so I can't debug with gdb.
>
> Putting aside any "that's probably not a great solution to the 
> problem you're tying to solve" thoughts, can anyone offer me 
> the "eureka" moment I'm missing to understand why the code 
> below doesn't work?
>
> Many thanks in advance!
>
> * * *
>
> import std.stdio;
>
> enum Suit {
> 	HEARTS, DIAMONDS, CLUBS, SPADES
> }
>
> enum Value {
> 	ACE = 1, TWO, THREE, FOUR, FIVE, SIX, SEVEN, EIGHT, NINE, TEN, 
> JACK, QUEEN, KING
> }
>
> struct Card {
> 	Value value;
> 	Suit suit;
> }
>
> void printCard(in Card card) {
> 	final switch(card.value) {
> 		case Value.ACE:
> 			write("A");
> 			break;
> 		case Value.TWO, Value.THREE, Value.FOUR, Value.FIVE, 
> Value.SIX, Value.SEVEN, Value.EIGHT, Value.NINE, Value.TEN:
> 			writef("%d", card.value);
> 			break;
> 		case Value.JACK:
> 			write("J");
> 			break;
> 		case Value.QUEEN:
> 			write("Q");
> 			break;
> 		case Value.KING:
> 			write("K");
> 			break;
> 	}
> 	final switch(card.suit) {
> 		case Suit.HEARTS:
> 			write("♡");
> 			break;
> 		case Suit.DIAMONDS:
> 			write("♢");
> 			break;
> 		case Suit.CLUBS:
> 			write("♣");
> 			break;
> 		case Suit.SPADES:
> 			write("♠");
> 			break;
> 	}
> 	write("\n");
> }
>
> int main() {
> 	auto card = Card(Value.JACK, Suit.CLUBS);
> 	printCard(card);
> 	return 0;
> }

It seems to be DMD specific, it works fine with ldc. If you're a 
homebrew user, brew install ldc and try it for yourself.

P.s. you can use the `with` statement to make things less verbose:

import std.stdio;

enum Suit {
	HEARTS, DIAMONDS, CLUBS, SPADES
}

enum Value {
	ACE = 1, TWO, THREE, FOUR, FIVE, SIX, SEVEN, EIGHT, NINE, TEN,
JACK, QUEEN, KING
}

struct Card {
	Value value;
	Suit suit;
}

void printCard(in Card card) {
	final switch(card.value) with(Value) {
		case ACE:
			write("A");
			break;
		case TWO, THREE, FOUR, FIVE, SIX, SEVEN, EIGHT, NINE, TEN:
			writef("%d", card.value);
			break;
		case JACK:
			write("J");
			break;
		case QUEEN:
			write("Q");
			break;
		case KING:
			write("K");
			break;
	}
	final switch(card.suit) with(Suit) {
		case HEARTS:
			write("♡");
			break;
		case DIAMONDS:
			write("♢");
			break;
		case CLUBS:
			write("♣");
			break;
		case SPADES:
			write("♠");
			break;
	}
	write("\n");
}

void main() {
	auto card = Card(Value.JACK, Suit.CLUBS);
	printCard(card);
}