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Rabiator
Joined: 17 Apr 2005
Posts: 289
Location: Sauerland
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 Posted: Fri Feb 27, 2009 8:53 am Post subject: FileSetTime doesn't work with composite parameters. |
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This works.
| Code: | FullDay = 20000101
FileSetTime, %FullDay%, c:\test.txt |
This doesn't. In lieu the file timestamp gets the actual date and time.
| Code: | Y = 2000
M = 01
D = 02
FileSetTime, %Y%%M%%D%, c:\test.txt |
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Lexikos
Joined: 17 Oct 2006
Posts: 7295
Location: Australia
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| Posted: Fri Feb 27, 2009 9:51 am Post subject: |
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Although it doesn't seem to be documented, it appears the first parameter of FileSetTime is an expression. As a result, %Y%%M%%D% is a double-deref. Since no variable with the name 20000102 exists, it gets an empty value. Try using an expression as demonstrated:
| Code: | Y = 2000
M = 01
D = 02
FileSetTime, Y M D, c:\test.txt |
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Rabiator
Joined: 17 Apr 2005
Posts: 289
Location: Sauerland
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| Posted: Fri Feb 27, 2009 2:46 pm Post subject: |
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Thanks, it works!
FileSetTime is the only command/function I know, that excepts a traditional and an expression variable.
This is slightly confusing. At least the intended behavior should be documented.  |
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Lexikos
Joined: 17 Oct 2006
Posts: 7295
Location: Australia
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| Posted: Sat Feb 28, 2009 12:26 am Post subject: |
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IIRC, only if(expression) and While(expression) don't support the traditional behaviour. I've tried briefly with WinMove; %var% and var are the same. I know this is also the case for Return. (%var%) and %var1%%var2% are always double-derefs, unlike %var%.
It seems only Return documents this. |
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Chris
Site Admin
Joined: 02 Mar 2004
Posts: 10716
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| Posted: Sat Feb 28, 2009 1:08 am Post subject: |
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Since this behavior has been in effect so long, it's probably best to leave it as it is. I've updated the documentation to read:
This parameter is an expression. Consequently, if multiple variables need to be concatenated to form a single timestamp, the dot operator should be used instead of percent signs. For example: FileSetTime, Year . Month . Day, C:\My File.txt
Thanks for reporting it. |
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Chris
Site Admin
Joined: 02 Mar 2004
Posts: 10716
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| Posted: Sat Feb 28, 2009 2:28 am Post subject: |
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| Lexikos wrote: | ...with WinMove; %var% and var are the same. I know this is also the case for Return. (%var%) and %var1%%var2% are always double-derefs, unlike %var%.
It seems only Return documents this. |
The reason is that parameters that are pure numbers didn't seem to have any need for concatenation like %x%%y% (e.g. not many scripts would concatenate '5' and '6' to form the number 56). When expressions were added to the language, it seemed useful to support them natively in numeric parameters because it could be achieved without sacrificing backward compatibility. This is documented in the Expressions section:
| Quote: | ...certain parameters of some commands are documented as accepting expressions, in which case the leading percent sign is permitted but not necessary. For example, all of the following are effectively identical because Sleep's first parameter is expression-capable: | Code: | Sleep MillisecondsToWait
Sleep %MillisecondsToWait%
Sleep % MillisecondsToWait |
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Return's parameter was intended from the beginning to be a pure expression, and there was no need for backward compatibility. Unfortunately, it wasn't discovered until a while afterward that it behaved like it was backward compatible anyway. But rather than risk breaking existing scripts, it was left that way (maybe it was the wrong decision).
Also, since return's behavior was different than users might expect (since return can accept both strings and numbers), this was documented explicitly on its page.
Anyway, it seemed best not to repeat the mistake that was made with return for new syntax like while-loop that is intended to be a pure expression. |
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Lexikos
Joined: 17 Oct 2006
Posts: 7295
Location: Australia
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| Posted: Sat Feb 28, 2009 2:49 am Post subject: |
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Thanks for the detailed explanation. I was aware of some of it, but mostly because I've been through the source code.
| Chris wrote: | | The reason is that parameters that are pure numbers didn't seem to have any need for concatenation like %x%%y% (e.g. not many scripts would concatenate '5' and '6' to form the number 56). |
I guess time stamps are the only exception.
| Quote: | | This is documented in the Expressions section: |
Although it demonstrates %var% and var are equivalent, it doesn't explain that this is an exception to expression syntax. For users that were not familiar with AutoHotkey before expressions were introduced, this might be confusing. |
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Chris
Site Admin
Joined: 02 Mar 2004
Posts: 10716
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| Posted: Sat Feb 28, 2009 12:08 pm Post subject: |
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Thanks; I've added the following to the expression operator table for percent signs: | Quote: | | Also, for backward compatibility, command parameters that are documented as "can be an expression" treat an isolated name in percent signs (e.g. %i%, but not Array%i%) as though the percent signs are absent. This can be avoided by enclosing the reference in parentheses; e.g. Sleep (%Var%) |
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Rabiator
Joined: 17 Apr 2005
Posts: 289
Location: Sauerland
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| Posted: Sat Feb 28, 2009 1:59 pm Post subject: |
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| Thank you both for clarifying and for updating the documentation! |
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flyingDman
Joined: 27 Feb 2009
Posts: 690
Location: Burbank, California
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| Posted: Fri Mar 05, 2010 1:06 am Post subject: |
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I thought I understood the previous posts here, but I am still puzzled. Why does this work:
| Code: | FormatTime, ts, %oVar2%, yyyyMMddHHmmss
FileSetTime, ts,%a_scriptdir%\%oVar1%
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and this does not:
| Code: | | FileSetTime, oVar2,%a_scriptdir%\%oVar1% |
variable oVar2 is in the "yyyyMMddHHmmss" format (actually it is the output of a FileGetTime of another script). I understand that because the 1st parameter is an expression, no %'s are to be used. But oVar2, w/o the %'s, is not recognized and the processed file(s) get today's stamp. Who can shed some light on this???.
_________________
"Data is not information, information is not knowledge, knowledge is not understanding, understanding is not wisdom" but let's start to get the data... |
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Rabiator
Joined: 17 Apr 2005
Posts: 289
Location: Sauerland
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| Posted: Fri Mar 05, 2010 5:31 pm Post subject: |
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| flyingDman wrote: | and this does not:
| Code: | | FileSetTime, oVar2,%a_scriptdir%\%oVar1% |
variable oVar2 is in the "yyyyMMddHHmmss" format (actually it is the output of a FileGetTime of another script). |
This works: | Code: | FileGetTime, oVar2, c:\file1.txt
FileSetTime, oVar2, c:\file2.txt |
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flyingDman
Joined: 27 Feb 2009
Posts: 690
Location: Burbank, California
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| Posted: Fri Mar 05, 2010 9:16 pm Post subject: |
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Thank you, that helped me find what the problem was: a simple space ... 
_________________
"Data is not information, information is not knowledge, knowledge is not understanding, understanding is not wisdom" but let's start to get the data... |
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