When using variables with percentages?

[852]

Hello,
I'm using AHK already for a while, but still have problems when to use variables with percentages and when without.
Some examples:

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EnvGet, var, %var%

Works as expected, reading with %, writing without.

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StringReplace, str, str, %separator%

Writing output variable without, but reading also while reading separator needs it.

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If InstallPath
IfExist %InstallPath%

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Loop, read, %FileName%
Loop, parse, A_LoopReadLine, CSV

Similar functions, every time different.

Is there a rule which I don't understand? I really like AHK , but try and error to find out how to use variables is very annoying. Any hints about that? Thanks already

[joedf]

Yeah, it can be a bit confusing... especially early on. Maybe this will help?
"When to use percents": https://www.autohotkey.com/docs/Tutorial.htm#s61

[852]

Unfortunately not really. I've read the help, but it doesn't feel to work like described.

When not to use percent signs:
In parameters that are input or output variables

This explains the case of StringReplace. But in the example of EnvGet it's also an input variable which need percents.
I don't see a difference between the input variables for both loops as well. Why are some "more input" than others?

When not to use percent signs:
On the left side of legacy (non-expression) if-statements

Explains the behavior of IfExists because it isn't an if-statement although it looks like one. Unintuitive, but at least this one I understand.

[BoBo]

@852 - the first thing you shouldn't do is to use deprecated commands. Those are only kept in place to provide backward compatibility to run old/outdated/unconverted scripts. That will solve instantly 50% of the problems mentioned above - as functions used instead are 'expression-styled'.

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Loop, read, %FileName%
Loop, parse, A_LoopReadLine, CSV

Similar functions, every time different.

Well, like shoes, but for different environments. Would you prefer sandals if walking through a pond of mud?
Loop, read - expects a static string parameter pointing to some content, so using a variable instead must be declared/made obvious in some way.
Loop, parse - expects the content itself, using a variable by default, no need to declaring it explicitly, right? Right.

Program languages are like wifes/husbands, you don't have to understand everything they say, simply accept it and doing it their way.