Boolean short circuiting

BlitzMax Forums/BlitzMax Programming/Boolean short circuiting

Ian C

(Posted 2005) [#1]

Hello all

I was just messing about to test whether bmax short-circuits boolean expressions, and it seems that it does:

Function F1:Int()
	Print "F1"
	Return True
End Function

Function F2:Int()
	Print "F2"
	Return True
End Function

If F1() Or F2()
	Print "TRUE"
EndIf

Does anyone know if this is intentional, and if so can I rely on it always being in the language, and on left to right ordering like C?

It's just that it's so damned handy!

Ian C

marksibly

(Posted 2005) [#2]

Does anyone know if this is intentional, and if so can I rely on it always being in the language, and on left to right ordering like C?

Yes, it's intentional and yes, it will always evaluate left to right.

MrCredo

(Posted 2005) [#3]

WOOOOOOOOOOOOOOOOW - i do not know this... i think this is the same how this works in C++...

test this in bb3d and bbmax. in bb3d this create a error - in blitzmax not!

nice

Type test
Field val:Int
EndType

Local xxx:test

If xxx<>Null And xxx.val=1 Then Print "COOL"
Print "OK"

taxlerendiosk

(Posted 2005) [#4]

That's very useful. Also, you can just use "If xxx" instead of "If xxx<>Null" I think.

morszeck

(Posted 2005) [#5]

that's old future.

Ian C

(Posted 2005) [#6]

Fantastic news Mark! Cheers for that.

And MrCredo it is very powerful and just the same as C++ works (and C# for that matter)... Rather than having to nest lots of if's for cheap over expensive operations, just do:

if CheapCollisionCheck() and ExpensiveCollisionCheck() ...

And you've done a handy bit of opimisation as ExpensiveCollisionCheck() won't be called if CheapCollisionCheck() was false :-)

Ian C