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Tip: IIf function
Posted: Fri Feb 09, 2007 2:00 pm
by PB
Code: Select all
Macro IIf (expr,truepart,falsepart)
If expr : truepart : Else : falsepart : EndIf
EndMacro
a=Random(1) : Debug a
b=Random(1) : Debug b
IIf(a=b, Debug "same", Debug "different")
Posted: Fri Feb 09, 2007 2:07 pm
by hellhound66
Removed.
Posted: Fri Feb 09, 2007 2:14 pm
by PB
It's a shorter way to do a test and return either a true or false result.
Truepart and falsepart are not meant to be a set of commands (like in
your example of For/Next), but just a single result. Some docs for it:
http://en.wikipedia.org/wiki/IIf
and
http://msdn.microsoft.com/library/defau ... fctIIF.asp
Posted: Fri Feb 09, 2007 6:28 pm
by netmaestro
Nice clean implementation, PB.
Posted: Fri Feb 09, 2007 6:48 pm
by dell_jockey
Nice indeed. A suggestion: you could extend the Wikipedia page with your PB implementation.... Would give you and PB some airtime...
Posted: Fri Feb 09, 2007 7:02 pm
by ts-soft
Using in this way?
Code: Select all
Macro IIf (expr,truepart,falsepart)
If expr : truepart : Else : falsepart : EndIf
EndMacro
a=Random(1) : Debug a
b=Random(1) : Debug b
IIf(a=b, x=1, x=0)
Debug x
Posted: Sat Feb 10, 2007 2:27 am
by SFSxOI
Very Nice! Thank You
Posted: Sat Feb 10, 2007 12:32 pm
by Flype
Nice.
It was already submitted by helpy one year ago.
he was very close to make it work but nobody replies.
http://www.purebasic.fr/english/viewtopic.php?t=19291
Posted: Sat Feb 10, 2007 12:36 pm
by PB
> Nice but already submitted by helpy one year ago
I didn't see those, but yeah, they don't work. He was very close, as you said.
Posted: Sun Feb 11, 2007 4:42 am
by netmaestro
The most useful form of the IIf command imho would be:
Code: Select all
Result$ = IIf ( (height > 190), "Tall", "Average" )
but I don't believe it's doable in straight PureBasic code (no boolean expressions). Can anyone make it work, perhaps with an asm approach? Or is it easier than it looks to me?
Posted: Tue Sep 18, 2007 5:03 pm
by Little John
How about this:
Code: Select all
Macro IIf (condition, target, trueVal, falseVal)
If condition
target = trueVal
Else
target = falseVal
EndIf
EndMacro
;-- Demo
IIf(3=4, msg$, "same", "not equal")
Debug msg$
Regards, Little John
Posted: Tue Sep 18, 2007 10:43 pm
by #NULL
like this i do it for integers:
Code: Select all
; if2.pbi
; by #Null
Procedure if2proc(condition, A.l, B.l)
If condition
ProcedureReturn A
Else
ProcedureReturn B
EndIf
EndProcedure
Macro if2(if2_condition, if2_A, if2_B)
if2proc( (0 Or (if2_condition)), if2_A, if2_B )
EndMacro
;Debug if2( 2>5, 123, 321)
like that for strings
Code: Select all
; strIf.pbi
; by #Null
; an ?-operator for stings. works like..
; expression ? string1 : string2
Macro StrIf( _StrIf_condition_, _StrIf_string_IF_, _StrIf_string_ELSE_="")
_StrIf_proc( 0 Or (_StrIf_condition_), _StrIf_string_IF_, _StrIf_string_ELSE_ )
EndMacro
Procedure.s _StrIf_proc( condition.l, stringIF.s, stringELSE.s)
If condition
ProcedureReturn stringIF
Else
ProcedureReturn stringELSE
EndIf
EndProcedure
; Debug "---- EXAMPLE - StrIf.pbi"
; For i=0 To 10
; r=Random(20)-10
; Debug StrIf(r>0,"+") + Str(r)
; Next
; Debug "----"
; For i=0 To 10
; r=Random(3)
; Debug StrIf(Not r,"no", Str(r)) + StrIf(r>1," seats", " seat")
; Next
; Debug "----"
..i didn't find an ultimate solution yet
Posted: Wed Sep 19, 2007 2:18 pm
by pdwyer
I don't understand the point of a one line macro in this case,
Can't you just type what's in the macro instead of the macro? Whats the benefit?
Perhaps because I can't see what everyone else sees is why I never use macros...
Posted: Wed Sep 19, 2007 2:45 pm
by Edwin Knoppert
In c# it works as should be:
int a = 1;
String T = a == 1 ? "1234" : "nope";
This means you can use inline stuff instead of using if's like:
if( Function1( a == 1 ? "1234" : "nope" ) )
{
}
Where Function1's param is a string in this case.
Posted: Thu Sep 20, 2007 1:55 pm
by Dreamland Fantasy
pdwyer wrote:I don't understand the point of a one line macro in this case,
Can't you just type what's in the macro instead of the macro? Whats the benefit?
Perhaps because I can't see what everyone else sees is why I never use macros...
Macros execute faster than procedures since the code is substituted where the calls to the macro are during compilation. This is one reason why people use them. Downside is that it can increase the size of the compiled code compared with using procedures.
The other reason is that it can save a lot of typing (and hence less chance of mistakes creeping into your code).
Here is an example of a macro from an image processing/converter program I wrote:
Code: Select all
Macro Normalize(Red, Green, Blue)
If Red < 0
Red = 0
ElseIf Red > 255
Red = 255
EndIf
If Green < 0
Green = 0
ElseIf Green > 255
Green = 255
EndIf
If Blue < 0
Blue = 0
ElseIf Blue > 255
Blue = 255
EndIf
EndMacro
Rather than write this out the long way every time I had to access it in various procedures all I do type is NormalizeRGB(RedValue, GreenValue, BlueValue). Also, because I have it as a macro instead of a procedure the execution time is a lot faster (imagine calling this as a procedure for every single pixel in a large image!
).
But, like you, I can't really see the point in the IIf() example unless it is to ease the conversion of some code from another programming environment.
Kind regards,
Francis.