• =?UTF-8?B?THXDrXM=?= Marques (6/6) Feb 13 2019 `static if` is defined in the D grammar as `static if (
• H. S. Teoh (11/15) Feb 13 2019 It's either an oversight, or was probably chosen just for consistency
• rikki cattermole (3/17) Feb 13 2019 Ugh...
• bauss (10/16) Feb 13 2019 I would agree with that it makes no sense that it's an

=?UTF-8?B?THXDrXM=?= Marques <luis luismarques.eu> writes:

`static if` is defined in the D grammar as `static if ( 
AssignExpression )`.
What's the point of AssignExpression, instead of just a 
ConditionalExpression?
In what situation can you even use `static if(x = y)?`, `static 
if(x += y)?`, etc?

"H. S. Teoh" <hsteoh quickfur.ath.cx> writes:

On Wed, Feb 13, 2019 at 04:45:39PM +0000, Luís Marques via Digitalmars-d wrote:
 `static if` is defined in the D grammar as `static if (
 AssignExpression )`.  What's the point of AssignExpression, instead of
 just a ConditionalExpression?  In what situation can you even use
 `static if(x = y)?`, `static if(x += y)?`, etc?

It's either an oversight, or was probably chosen just for consistency
with the normal `if` condition (to make it simpler to implement in the
compiler since we could just use the same code for parsing the
condition).

Though, in an extreme case, one could potentially have a user-defined
that overloads += to return bool at compile-time.  Probably an example
of operator overload abuse, though.


T

-- 
I don't trust computers, I've spent too long programming to think that they can
get anything right. -- James Miller

rikki cattermole <rikki cattermole.co.nz> writes:

On 14/02/2019 6:33 AM, H. S. Teoh wrote:
 On Wed, Feb 13, 2019 at 04:45:39PM +0000, Luís Marques via Digitalmars-d
wrote:
 `static if` is defined in the D grammar as `static if (
 AssignExpression )`.  What's the point of AssignExpression, instead of
 just a ConditionalExpression?  In what situation can you even use
 `static if(x = y)?`, `static if(x += y)?`, etc?

 
 It's either an oversight, or was probably chosen just for consistency
 with the normal `if` condition (to make it simpler to implement in the
 compiler since we could just use the same code for parsing the
 condition).
 
 Though, in an extreme case, one could potentially have a user-defined
 that overloads += to return bool at compile-time.  Probably an example
 of operator overload abuse, though.

Ugh...

https://github.com/dlang/dmd/blob/master/src/dmd/parse.d#L2407

bauss <jj_1337 live.dk> writes:

On Wednesday, 13 February 2019 at 16:45:39 UTC, Luís Marques 
wrote:
 `static if` is defined in the D grammar as `static if ( 
 AssignExpression )`.
 What's the point of AssignExpression, instead of just a 
 ConditionalExpression?
 In what situation can you even use `static if(x = y)?`, `static 
 if(x += y)?`, etc?

I would agree with that it makes no sense that it's an 
AssignExpression.

It would've made more sense if the normal if statement was an 
AssignExpression, but even that isn't.

I don't believe there are any situations where you'd end up with 
an AssignExpression as the condition for a static if statement.

Either there is a magic reason for some compiler bug that it 
avoids OR it's a simple mistake.