Bug (or strange behaviour) with sub macros

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LocoDelAssembly
Your code has a bug

Joined: 06 May 2005
Posts: 4623
Location: Argentina

LocoDelAssembly 16 Jul 2007, 01:21

Code:

macro test param
{
  macro sub_test param
  \{
    display param+'0'
  \}
  sub_test ; Works always
  sub_test 5 ; Fails if test didn't recieve a paramenter
}

macro test2 param
{
  display "OK, no problem without a param", 13, 10
}

test2  ; Works
test 1 ; Works, displays "05"
test   ; Fails at second sub_test line

By some strange reason sub_test can't recieve a parameter if test macro didn't recieve one. This only happens when the name of the test formal parameter is the same in sub_test, otherwise this works.

16 Jul 2007, 01:21

vid
Verbosity in development

Joined: 05 Sep 2003
Posts: 7103
Location: Slovakia

vid 16 Jul 2007, 07:42

of course, because name of sub_test parameter is param, and that is also name of test's parameter.

before "test" is being preprocessed, all occurences of "param" in it's body are replaced by it's value. In your case, line "macro sub_test param" becomes "macro sub_test", and after that it is preprocessed.

16 Jul 2007, 07:42

LocoDelAssembly
Your code has a bug

Joined: 06 May 2005
Posts: 4623
Location: Argentina

LocoDelAssembly 16 Jul 2007, 14:46

Quote:

before "test" is being preprocessed, all occurences of "param" in it's body are replaced by it's value

I don't believe that. That means that in some moment "macro sub_test param" becomes "macro sub_test 1" because as you said param gets replaced, however the example prints "05", not "00" nor "01" nor error because using 1 as symbol when you can't.

[edit]Ahp, you CAN use a number as formal param Confused

The code below works always. Sorry for the misunderstood

Code:

macro test param
{ 
  macro sub_test 1
  \{ 
    display 1+'0'
  \} 
  sub_test ; Works always 
  sub_test 5 ; Works always
} 

macro test2 param 
{ 
  display "OK, no problem without a param", 13, 10 
} 

test2  ; Works 
test  ; Works, displays "05"

[/edit]

16 Jul 2007, 14:46

vid
Verbosity in development

Joined: 05 Sep 2003
Posts: 7103
Location: Slovakia

vid 16 Jul 2007, 21:37

no problem, i hope problem is solved now Wink

16 Jul 2007, 21:37

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