Hi,

No wonder that it works, because it is the legacy C++ (and I like that everything is different from zero is true):

if (5)
    writeln("OK"); // prints OK

In the `static if` this condition also works perfectly:

static if (5)
    writeln("OK"); // prints OK

Here idiomatic version check in the hash key:

int[int] hash = [1 : 3, 5 : 7];

	if (hash.get(5, false))
		writeln("OK"); // prints OK

In the `static if` this condition also works perfectly:

immutable hash = [1 : 3, 5 : 7];

static if (hash.get(5, false))
    writeln("OK"); // prints OK

It's not quite idiomatic version to check if a key in the hash:

int[int] hash = [1 : 3, 5 : 7];

if (5 in hash)
    writeln("OK"); // prints OK

The problem is that the `static if` it does not work:

immutable hash = [1 : 3, 5 : 7];

static if (5 in hash)
    writeln("OK");
// Error: expression &[1:3, 5:7][5]
// is not constant or does not evaluate to a bool

You have to write something like that :)

immutable hash = [1 : 3, 5 : 7];

static if (!!(5 in hash))
    writeln("OK"); // prints OK

Pulls whether this issue? Or is it normal?

On Saturday, 6 June 2015 at 17:06:37 UTC, Dennis Ritchie wrote:
> The problem is that the `static if` it does not work:
>
> immutable hash = [1 : 3, 5 : 7];
>
> static if (5 in hash)
>     writeln("OK");
> // Error: expression &[1:3, 5:7][5]
> // is not constant or does not evaluate to a bool
>
> You have to write something like that :)
>
> immutable hash = [1 : 3, 5 : 7];
>
> static if (!!(5 in hash))
>     writeln("OK"); // prints OK
>
> Pulls whether this issue? Or is it normal?

http://dlang.org/version.html#staticif:

> StaticIfCondition:
>    static if ( AssignExpression )
>
> AssignExpression is implicitly converted to a boolean type, and is evaluated at compile time. The condition is satisfied if it evaluates to true. It is not satisfied if it evaluates to false.

So, I suppose it's should work without casting to bool or `!is` operator.

On Saturday, 6 June 2015 at 18:16:28 UTC, sigod wrote:
> On Saturday, 6 June 2015 at 17:06:37 UTC, Dennis Ritchie wrote:
>> Pulls whether this issue? Or is it normal?
>
> http://dlang.org/version.html#staticif:
>
>> StaticIfCondition:
>>    static if ( AssignExpression )
>>
>> AssignExpression is implicitly converted to a boolean type, and is evaluated at compile time. The condition is satisfied if it evaluates to true. It is not satisfied if it evaluates to false.
>
> So, I suppose it's should work without casting to bool or `!is` operator.

I reported this:
https://issues.dlang.org/show_bug.cgi?id=14659

On Saturday, 6 June 2015 at 17:06:37 UTC, Dennis Ritchie wrote:
> [snip]

`static if(5 in hash) {}` will not work because (5 in hash) returns a pointer to the value or null if the key oesn't exist.

bye,
lobo

On Sunday, 7 June 2015 at 03:01:15 UTC, lobo wrote:
> On Saturday, 6 June 2015 at 17:06:37 UTC, Dennis Ritchie wrote:
>> [snip]
>
> `static if(5 in hash) {}` will not work because (5 in hash) returns a pointer to the value or null if the key oesn't exist.
>
> bye,
> lobo

just to be clear, you cannot have a pointer to anything at compile time because it doesn't exist and IMO changing 'in' to behave differently for static-if compared  runtime if would be bad.

On Sunday, 7 June 2015 at 03:04:38 UTC, lobo wrote:
> On Sunday, 7 June 2015 at 03:01:15 UTC, lobo wrote:
>> On Saturday, 6 June 2015 at 17:06:37 UTC, Dennis Ritchie wrote:
>>> [snip]
>>
>> `static if(5 in hash) {}` will not work because (5 in hash) returns a pointer to the value or null if the key oesn't exist.
>>
>> bye,
>> lobo
>
> just to be clear, you cannot have a pointer to anything at compile time because it doesn't exist and IMO changing 'in' to behave differently for static-if compared  runtime if would be bad.

This, of course, it is logical, but it somehow works:

immutable hash = [1 : 3, 5 : 7];

static if (!!(5 in hash))
    writeln("OK"); // prints OK

On Sunday, 7 June 2015 at 03:04:38 UTC, lobo wrote:
> On Sunday, 7 June 2015 at 03:01:15 UTC, lobo wrote:
>> On Saturday, 6 June 2015 at 17:06:37 UTC, Dennis Ritchie wrote:
>>> [snip]
>>
>> `static if(5 in hash) {}` will not work because (5 in hash) returns a pointer to the value or null if the key oesn't exist.
>>
>> bye,
>> lobo
>
> just to be clear, you cannot have a pointer to anything at compile time because it doesn't exist and IMO changing 'in' to behave differently for static-if compared  runtime if would be bad.

Not true:

    immutable y = 1;
    enum x = &y;

You can even do pointer arithmetics:

    auto foo() {
        auto x = [1,2,3,4];
        auto y = &x[1];
        return y[2];
    }
    pragma(msg, foo());

On Sunday, 7 June 2015 at 11:33:56 UTC, Marc Schütz wrote:
> Not true:
>
>     immutable y = 1;
>     enum x = &y;
>
> You can even do pointer arithmetics:
>
>     auto foo() {
>         auto x = [1,2,3,4];
>         auto y = &x[1];
>         return y[2];
>     }
>     pragma(msg, foo());

Then I do not see any problems hindering satisfy my report :)