Compiler bug with 'if defined/else'?

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ejamesr

Joined: 04 Feb 2011
Posts: 52
Location: Provo, Utah, USA

ejamesr 04 Nov 2012, 03:17

In the following, TEST_2 is always defined even though it should not be. I've tested this in v1.70.03 and v1.71.05:

Code:

; With the if statement below, TEST_2 is always defined,
; whether the next line is commented out or not:
define TEST_1 1

if defined TEST_1
   display 'TEST_1 was defined',13,10
else
   ; this next define will always happen
   ; this is not correct...
   define TEST_2 1
   display 'TEST_2 was defined',13,10
end if

if defined TEST_2
   display 'TEST_2 is always defined',13,10
   display 'no matter the status',13,10
   display 'of TEST_1',13,10
end if

if ~ defined TEST_1
   display 'TEST_1 was not defined',13,10
else
   display 'TEST_1 was defined',13,10
end if

Has anyone else noticed this? Is there a work around?

I'm trying to define some equates conditionally, based on other equates. If this is truly a bug and the behavior is 'fixed', a lot of existing code may break. So for now, I will have to list each equate separately and just comment out the ones I don't want; I haven't found another way for this to work.

Alternatively, I hope somebody can point me to the errors of my ways above -- thank you!

ejamesr

04 Nov 2012, 03:17

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 19873
Location: In your JS exploiting you and your system

revolution 04 Nov 2012, 03:40

The problem here is that you are mixing the preprocessor with the assembler. define and equ are preprocessor directives and are processed during the preprocessing pass before the if statements are evaluated by the assembler.

A method to solve this for you is to use the assembler equals (=) instead of define.

Code:

TEST_1 = 1
if defined TEST_1
;...

04 Nov 2012, 03:40

ejamesr

Joined: 04 Feb 2011
Posts: 52
Location: Provo, Utah, USA

ejamesr 04 Nov 2012, 03:50

revolution,

Thank you -- that works perfectly (as long as BOTH symbols are defined with equals).

04 Nov 2012, 03:50

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 19873
Location: In your JS exploiting you and your system

revolution 04 Nov 2012, 04:24

ejamesr wrote:

Thank you -- that works perfectly (as long as BOTH symbols are defined with equals).

Yes. All variables will need to use the same method. The important thing is to understand the preprocessor/assembler paradigm.

04 Nov 2012, 04:24

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