simulating C-style three-parameter for-loop with ??=
Posted: 16 Sep 2023, 17:04
Code: Select all
while(i??=0, i++, i<=5)
{
Msgbox(i)
}
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simulating C-style three-parameter for-loop with ??=
https://www.autohotkey.com/boards/viewtopic.php?f=92&t=121514
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Re: simulating C-style three-parameter for-loop with ??=
Posted: 16 Sep 2023, 17:48
I don't think its silly or useless, if it were to work...
Generates an error for me (v2)
Missing operand.
Specifically: ??=0, i++, i<=5)
Should it work?
This worked
Code: Select all
i := 0
while(i++ < 5)
{
Msgbox(i)
}
Re: simulating C-style three-parameter for-loop with ??=
Posted: 16 Sep 2023, 18:06
Sorry, forgot to mention that ??= is (as of now) only available in alpha v2.1-alpha.2+
https://www.autohotkey.com/docs/alpha/Variables.htm#maybe-assign
[v2.1-alpha.2+]: x ??= y is shorthand for x := x ?? y. y is evaluated and assigned to x only if x is unset. This provides a succinct way to initialize a variable, property or array/map element only if it didn't already have a value.
Re: simulating C-style three-parameter for-loop with ??=
Posted: 16 Sep 2023, 18:09
see here: viewtopic.php?f=76&t=111881&p=539315#p539315 and the original post here: viewtopic.php?f=96&t=88725&p=511074&hilit=range#p511074
Re: simulating C-style three-parameter for-loop with ??=
Posted: 16 Sep 2023, 18:37
Nice... user defined counter, with step. Thanks!flyingDman wrote: ↑16 Sep 2023, 18:09see here: viewtopic.php?f=76&t=111881&p=539315#p539315 and the original post here: viewtopic.php?f=96&t=88725&p=511074&hilit=range#p511074
Andy
Re: simulating C-style three-parameter for-loop with ??=
Posted: 16 Sep 2023, 18:40
Re: simulating C-style three-parameter for-loop with ??=
Posted: 16 Sep 2023, 18:45
Thank @Descolada ! (I would'nt have been able to come up with that!!andymbody wrote: ↑16 Sep 2023, 18:37Nice... user defined counter, with step. Thanks!flyingDman wrote: ↑16 Sep 2023, 18:09see here: viewtopic.php?f=76&t=111881&p=539315#p539315 and the original post here: viewtopic.php?f=96&t=88725&p=511074&hilit=range#p511074
Andy
)Re: simulating C-style three-parameter for-loop with ??=
Posted: 16 Sep 2023, 19:12
Nice! Here's another C-style idiom: the downto operator denoted by -->
Works perfectly in AutoHotkey too!
Code: Select all
x := 10
while (x --> 0) ; x downto 0
msgbox x
Re: simulating C-style three-parameter for-loop with ??=
Posted: 16 Sep 2023, 20:13
Wow! Not documented i guess (could not find it)!
Re: simulating C-style three-parameter for-loop with ??=
Posted: 16 Sep 2023, 21:22
Will do... me neither... I struggle to comprehend lambdas. I probably should try to use them more so they become familiar.flyingDman wrote: ↑16 Sep 2023, 18:45Thank @Descolada ! (I would'nt have been able to come up with that!!
Re: simulating C-style three-parameter for-loop with ??=
Posted: 11 Oct 2023, 09:10
andymbody wrote: ↑16 Sep 2023, 17:48I don't think its silly or useless, if it were to work...
Generates an error for me (v2)
Missing operand.
Specifically: ??=0, i++, i<=5)
Should it work?
This workedCode: Select all
i := 0 while(i++ < 5) { Msgbox(i) }
Code: Select all
#requires Autohotkey v2.0
while(i := i ?? 0, i++, i <= 5)
{
msgbox(i)
}Re: simulating C-style three-parameter for-loop with ??=
Posted: 11 Oct 2023, 18:42
Code: Select all
while x --> 0Code: Select all
while (x--) > 0Re: simulating C-style three-parameter for-loop with ??=
Posted: 12 Oct 2023, 09:28
Actually if you reverse the arrow you can control the speed:
1x speed
5x speed!!!
1x speed
Code: Select all
x := 100
while (0 <-- x) ; x downto 0
MsgBox x
Code: Select all
x := 100
while (0 <---------- x) ; x downto 0 but 5 times as fast
MsgBox x
Re: simulating C-style three-parameter for-loop with ??=
Posted: 12 Oct 2023, 09:52
Re: simulating C-style three-parameter for-loop with ??=
Posted: 13 Oct 2023, 10:10
No any «magic». Just a consistent decreasing of variable's value. Such as:
Code: Select all
while ( 0 < (--x, --x, --x, --x, --x) )Re: simulating C-style three-parameter for-loop with ??=
Posted: 13 Oct 2023, 10:27
Ah... thanks
Re: simulating C-style three-parameter for-loop with ??=
Posted: 13 Oct 2023, 17:31
The C construct for (initializer; condition; step) evaluates step only after the first iteration, whereas while(i??=0, i++, i<=5) evaluates i++ before the first iteration, therefore starting at 1 rather than the value set by the initializer. The C construct also evaluates the initializer regardless of whether some variable is initialized or not, whereas while(i??=0... is prone to error if you happen to reuse the variable name "i" without considering its prior value.