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Zohar

[Closed] What Are "Unnamed Temporary Variables"?

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Zohar

Hi

 

If you go to AutoIt Help file, and enter "ByRef", then the relevant paragraph contains this interesting part:

"Note that not only a named variable can be passed for a ByRef parameter; unnamed temporary variables, such as function return values, may be passed as ByRef parameters as well. A literal can not be passed to a ByRef parameter."

 

What are unnamed temporary variables?

I have never seen those in code..

If anyone has a sample, it would be nice to see.

 

Thank you

Zohar
 

Edited by Zohar

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trancexx

It means rvalues.

That could confuse even more, so the explanation is extended deliberatly to cover uneducated users.

For example, return value of a function is rvalue that you can save to a variable, or pass as an argument (even byref) to another function.

Edited by trancexx

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eMyvnE

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mLipok

It means rvalues.

That could confuse even more, so the explanation is extended deliberatly to cover uneducated users.

For example, return value of a function is rvalue that you can save to a variable, or pass as an argument (even byref) to another function.

 

EDIT: Interesting.

You mean something like this?

ConsoleWrite(_F1(_F2('abc')) & @CRLF)

Func _F1(ByRef $sTextF1)
    StringUpper($sTextF1)
EndFunc   ;==>_F1

Func _F2($sTextF2)
    Return $sTextF2
EndFunc   ;==>_F2

Console output:

>"C:\Program Files (x86)\AutoIt3\SciTE\AutoIt3Wrapper\AutoIt3Wrapper.exe" /prod /AU3Check /in "L:\TEST_BYREF.au3"
+>21:14:39 Starting AutoIt3Wrapper v.2.1.4.5 SciTE v.3.3.9.0 Keyboard:00000415 OS:WIN_7/Service Pack 1 CPU:X64 OS:X64 Environment(Language:0415)
>Running AU3Check (3.3.10.2) from:C:\Program Files (x86)\AutoIt3 input:L:\TEST_BYREF.au3
"L:\TEST_BYREF.au3"(4,25) : error: _F1() previously called with Const or expression on ByRef param(s).
Func _F1(ByRef $sTextF1)
~~~~~~~~~~~~~~~~~~~~~~~~^
"L:\TEST_BYREF.au3"(2,28) : REF: first call to _F1().
ConsoleWrite(_F1(_F2('abc'))
~~~~~~~~~~~~~~~~~~~~~~~~~~~^
L:\TEST_BYREF.au3 - 1 error(s), 0 warning(s)
!>21:14:39 AU3Check ended. Press F4 to jump to next error.rc:2
+>21:14:39 AutoIt3Wrapper Finished..
>Exit code: 0 Time: 0.8017


"Note that not only a named variable can be passed for a ByRef parameter; unnamed temporary variables, such as function return values, may be passed as ByRef parameters as well. A literal can not be passed to a ByRef parameter."

 

lost one word.

 

Note that not only a named variable can be passed for a ByRef parameter - unnamed temporary variables, such as function return values, may be passed as ByRef parameters as well. However, a literal cannot be passed to a ByRef parameter.

Edited by mLipok

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Anticipating Errors :  "Any program that accepts data from a user must include code to validate that data before sending it to the data store. You cannot rely on the data store, ...., or even your programming language to notify you of problems. You must check every byte entered by your users, making sure that data is the correct type for its field and that required fields are not empty."

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trancexx

Au3Check is bullshit tool that should be completely rewritten before used. There you see just another of its bugs.

AutoIt language has its own rules that Au3Check attempts to follow, often failing. Disable it and you will see AutoIt interpreter runs that code just fine.

Edited by trancexx

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Jos

don't run au3check on this one as it can't handle this code and think you have an logic error in the example:

#AutoIt3Wrapper_Run_Au3Check=n
ConsoleWrite(_F2('abc') & @CRLF)
ConsoleWrite(_F1(_F2('abc')) & @CRLF)

Func _F1(ByRef $sTextF1)
    Return StringUpper($sTextF1)
EndFunc   ;==>_F1

Func _F2($sTextF2)
    Return $sTextF2
EndFunc   ;==>_F2

Jos


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mLipok

Au3Check is bullshit tool that should be completely rewritten before used. There you see just another of its bugs.

AutoIt language has its own rules that Au3Check attempts to follow, often failing. Disable it and you will see AutoIt interpreter runs that code just fine.

 

But at the same time is quite a useful tool.

EDIT: At least me useful every day.


I forget about Return from _F1()

here is complete example script:

#AutoIt3Wrapper_Run_Au3Check=n
ConsoleWrite('Result:' & _F1(_F2('abc')) & @CRLF)

Func _F1(ByRef $sTextF1)
    Return StringUpper($sTextF1)
EndFunc   ;==>_F1

Func _F2($sTextF2)
    Return $sTextF2
EndFunc   ;==>_F2
Edited by mLipok

Signature beginning:   Wondering who uses AutoIT and what it can be used for ?
* GHAPI UDF - modest begining - comunication with GitHub REST API *
ADO.au3 UDF     POP3.au3 UDF     XML.au3 UDF    How to use IE.au3  UDF with  AutoIt v3.3.14.x  for other useful stuff click the following button

Spoiler

Any of my own code posted anywhere on the forum is available for use by others without any restriction of any kind. 

My contribution (my own projects): * Debenu Quick PDF Library - UDF * Debenu PDF Viewer SDK - UDF * Acrobat Reader - ActiveX Viewer * UDF for PDFCreator v1.x.x * XZip - UDF * AppCompatFlags UDF * CrowdinAPI UDF * _WinMergeCompare2Files() * _JavaExceptionAdd() * _IsBeta() * Writing DPI Awareness App - workaround * _AutoIt_RequiredVersion() * Chilkatsoft.au3 UDF * TeamViewer.au3 UDF * JavaManagement UDF * VIES over SOAP * WinSCP UDF * GHAPI UDF - modest begining - comunication with GitHub REST API *

My contribution to others projects or UDF based on  others projects: * _sql.au3 UDF  * POP3.au3 UDF *  RTF Printer - UDF * XML.au3 UDF * ADO.au3 UDF SMTP Mailer UDF *

Useful links: * Forum Rules * Forum etiquette *  Forum Information and FAQs * How to post code on the forum * AutoIt Online Documentation * AutoIt Online Beta Documentation * SciTE4AutoIt3 getting started * Convert text blocks to AutoIt code * Games made in Autoit * Programming related sites * Polish AutoIt Tutorial * DllCall Code Generator * 

Wiki: Expand your knowledge - AutoIt Wiki * Collection of User Defined Functions * How to use HelpFile * Good coding practices in AutoIt * 

IE Related:  * How to use IE.au3  UDF with  AutoIt v3.3.14.x * Why isn't Autoit able to click a Javascript Dialog? * Clicking javascript button with no ID * IE document >> save as MHT file * IETab Switcher (by LarsJ ) * HTML Entities * _IEquerySelectorAll() (by uncommon) * 

I encourage you to read: * Global Vars * Best Coding Practices * Please explain code used in Help file for several File functions * OOP-like approach in AutoIt * UDF-Spec Questions *  EXAMPLE: How To Catch ConsoleWrite() output to a file or to CMD *

"Homo sum; humani nil a me alienum puto" - Publius Terentius Afer
"Program are meant to be read by humans and only incidentally for computers and execute" - Donald Knuth, "The Art of Computer Programming"
:naughty:  :ranting:, be  :) and       \\//_.

Anticipating Errors :  "Any program that accepts data from a user must include code to validate that data before sending it to the data store. You cannot rely on the data store, ...., or even your programming language to notify you of problems. You must check every byte entered by your users, making sure that data is the correct type for its field and that required fields are not empty."

Signature last update: 2018-03-17

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