Re^4: Unhappy returns

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Re^5: Unhappy returns by ysth (Canon) on Oct 10, 2005 at 15:23 UTC
I'd have to disagree. Every runtime statement in perl does have a return value. It's not true that foreach doesn't return anything. Ponder this piece of code: `@x = sub { 0; for (4,3,2) { 1 } }->();` [download] What does the sub return? Is it a bug? What should it return? (It has to return something, even if it's an empty list.) Also compare to `@x = sub { }->();` [download] and `$x = sub { 0; for (4,3,2) { 1 } }->();` [download]	[reply] [d/l] [select]
Re^6: Unhappy returns by Aristotle (Chancellor) on Oct 10, 2005 at 15:30 UTC
What does the sub return? The `foreach` in your examples is a red herring. A function call is an expression. And function calls return the value of the last expression evaluated. `foreach` is not an expression, but in the course of its execution several of those may be evaluated. My statement stands. (Pun intended.) Makeshifts last the longest.	[reply]
Re^7: Unhappy returns by ysth (Canon) on Oct 10, 2005 at 18:10 UTC
Then where does the return value come from? What expression is it? And function calls return the value of the last expression evaluated. I think it is possible to have a mostly consistent understanding based on that "rule", but it involves thinking of void-context expressions as having values. IMO it is a lot simpler (and completely instead of mostly consistent) to think of every statement as having a context and a return value. This issue with for loops is one place where the two models show their difference.	[reply]
Re^8: Unhappy returns by Aristotle (Chancellor) on Oct 10, 2005 at 19:22 UTC
Re^6: Unhappy returns by sauoq (Abbot) on Oct 10, 2005 at 17:01 UTC
It's not true that foreach doesn't return anything. Sure it is. Otherwise, you would not have had to wrap your example `for` loops in a sub to try to make your point. If it returned something, you'd be able to write code like: `@x = for (1) { 1 };` But, that's a syntax error. Why? Because statements don't return anything. Q.E.D. -sauoq "My two cents aren't worth a dime.";	[reply] [d/l] [select]
Re^7: Unhappy returns by ysth (Canon) on Oct 10, 2005 at 18:00 UTC
Sure it is. Otherwise, you would not have had to wrap your example for loops in a sub to try to make your point. I wrapped it in a sub because that's one way to put a for loop in a non-void context. Note that the very fact that I am speaking of the "context" of a statement demonstrates that statements can be said to have return values. But also see the reply I'm about to make to Re^5: Unhappy returns. `@x = for (1) { 1 };` But, that's a syntax error. Why? Because statements don't return anything. No, it's a syntax error because the whole thing is a statement that is an expression (one of the possible kinds of statement), and the expression is a list assignment which has the form expression = expression. So all you've proved is that `for (1) { 1 }` isn't an expression. IMO by your argument, `@x = do { for (1) { 1 } };` should be a syntax error, too, and it isn't.	[reply] [d/l] [select]
Re^8: Unhappy returns by Aristotle (Chancellor) on Oct 10, 2005 at 18:38 UTC
Re^9: Unhappy returns by ysth (Canon) on Oct 11, 2005 at 04:33 UTC
Re^8: Unhappy returns by sauoq (Abbot) on Oct 10, 2005 at 20:42 UTC
Re^9: Unhappy returns by Perl Mouse (Chaplain) on Oct 11, 2005 at 09:38 UTC


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