Page 1 of 1
Should Define be allowed for procedure parameters?
Posted: Tue Jun 18, 2019 1:33 am
by Demivec
I had a hard time trying to name this topic.
Here is the reference code:
Code: Select all
Procedure bad(a = 5)
Define a = 4 ;I'm don't think this declaration should be allowed
ProcedureReturn a
EndProcedure
Debug bad(3) ;displays 4
I had never dreamed that you could redeclare a procedure's parameter. Yes it must be of a matching type but it can also have an initial value assigned. It would seem it is treated as a regular assignment and no error is thrown.
What are people's thoughts on this?
I am going to have to rewrite my rule book now to cover this so that it doesn't slip in by accident and cause a bug.
Re: Should Define be allowed for procedure parameters?
Posted: Tue Jun 18, 2019 2:03 am
by wombats
I don't think it should be allowed as it is a duplicate identifier. If you change Define to Protected or Static, it then throws an error.
Re: Should Define be allowed for procedure parameters?
Posted: Tue Jun 18, 2019 7:22 am
by #NULL
Redeclaration errors are not very consitent.
Code: Select all
Debug "----------------------------- 13:"
; Global does not complain about redeclaration as long as the type does not change. That includes
; the case where the second declaration does not use any type and intends to use the default type
Global g13.a = 255 ; somewhere
; ...
Global g13 ; assume integer and zero-initialization?
g13 + 1
Debug g13 ; 0
Procedure p13()
Global g13
g13 + 1
Debug g13 ; 1
EndProcedure
p13()
Debug "----------------------------- 14:"
; Define does not complain about redeclaration but gives error for different implicit type
Define d14 = 100 ; somewhere
; ...
Define d14 ; assume zero-initialization?
d14 + 1
Debug d14 ; 101
Define d14b.a
;Define d14b ; error: Variable already declared with another type
Procedure p14()
Define d14 = 200
; ...
Define d14 ; assume zero-initialization?
d14 + 1
Debug d14 ; 201
Define d14_.a = 200
;Define d14_ ; error: Variable already declared with another type
EndProcedure
p14()
Debug "----------------------------- 15:"
; Protected does not allow redeclaration at all
Procedure p15()
Protected d15
;Protected d15 ; error: Local variable already declared
EndProcedure
Re: Should Define be allowed for procedure parameters?
Posted: Tue Jun 18, 2019 7:42 am
by Mijikai
I always thought Define is only meant to be used for procedures (ex. Define.i Hello()).
Re: Should Define be allowed for procedure parameters?
Posted: Tue Jun 18, 2019 7:49 am
by #NULL
Mijikai wrote:I always thought Define is only meant to be used for procedures (ex. Define.i Hello()).
You're confusing it with
Declare
Define is used with EnableExplicit for main-local variables (that are not arrays or lists), i.e. variables in the main scope that are not global / not visible in procedures (without Shared).
Define in procedures behaves like Protected.
Re: Should Define be allowed for procedure parameters?
Posted: Tue Jun 18, 2019 7:58 am
by #NULL
Also, you can't shadow a global with procedure-local Define, but you can with a parameter variable.
Code: Select all
Global g = 99
Procedure p1(g = 11)
Debug g
EndProcedure
Procedure p2()
Define g = 22 ; error: Variable already declared with a different scope
Debug g
EndProcedure
p1()
p2()
Re: Should Define be allowed for procedure parameters?
Posted: Tue Jun 18, 2019 8:06 am
by Mijikai
#NULL wrote:Mijikai wrote:I always thought Define is only meant to be used for procedures (ex. Define.i Hello()).
You're confusing it with
Declare
...
My morning coffee wasnt strong enough
Thanks for waking me up
