[Closed] What Are "Unnamed Temporary Variables"?

[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 February 21, 2014 by Zohar

[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 February 16, 2014 by trancexx

[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 February 16, 2014 by mLipok

[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 February 16, 2014 by trancexx

[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

[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 February 16, 2014 by mLipok