simulating C-style three-parameter for-loop with ??=

[bonobo]

Code: Select all

while(i??=0, i++, i<=5)
{
	Msgbox(i)
}

Silly/useless, but I can't help it.

[andymbody]

Silly/useless, but I can't help it.

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)
}

[bonobo]

Silly/useless, but I can't help it.

I don't think its silly or useless, if it were to work...

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.

[flyingDman]

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

[andymbody]

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

Nice... user defined counter, with step. Thanks!
Andy

[andymbody]

Sorry, forgot to mention that ??= is (as of now) only available in alpha v2.1-alpha.2+

Thank for the clarification! And the tip...

[flyingDman]

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

Nice... user defined counter, with step. Thanks!
Andy

Thank @Descolada ! (I would'nt have been able to come up with that!! )

[iseahound]

Nice! Here's another C-style idiom: the downto operator denoted by -->

Code: Select all

x := 10
while (x --> 0) ; x downto 0
   msgbox x

Works perfectly in AutoHotkey too!

[flyingDman]

Wow! Not documented i guess (could not find it)!

[andymbody]

Thank @Descolada ! (I would'nt have been able to come up with that!! )

Will do... me neither... I struggle to comprehend lambdas. I probably should try to use them more so they become familiar.

[vmech]

Silly/useless, but I can't help it.

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)
}

Code: Select all

#requires Autohotkey v2.0
while(i := i ?? 0, i++, i <= 5)
{
	msgbox(i)
}

[ntepa]

Code: Select all

while x --> 0

is really just:

Code: Select all

while (x--) > 0

[iseahound]

Actually if you reverse the arrow you can control the speed:

1x speed

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x := 100
while (0 <-- x) ; x downto 0
   MsgBox x

5x speed!!!

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x := 100
while (0 <---------- x) ; x downto 0 but 5 times as fast
   MsgBox x

[andymbody]

Actually if you reverse the arrow you can control the speed:

What kind of wizardry is this?

[vmech]

Actually if you reverse the arrow you can control the speed:

What kind of wizardry is this?

No any «magic». Just a consistent decreasing of variable's value. Such as:

Code: Select all

while ( 0 < (--x, --x, --x, --x, --x) )

[andymbody]

Code: Select all

while ( 0 < (--x, --x, --x, --x, --x) )

Ah... thanks

[lexikos]

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.