How to check definition

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Jin X

Joined: 06 Mar 2004
Posts: 133
Location: Russia

Jin X 16 Dec 2020, 09:44

How can I check if 'i' is defined?

Code:

define i mov

I can't use

Code:

if defined i

Maybe match? But how to use it in this case?

16 Dec 2020, 09:44

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20343
Location: In your JS exploiting you and your system

revolution 16 Dec 2020, 09:46

Code:

define i mov
match =i,i { display 'i is not defined'}

16 Dec 2020, 09:46

Jin X

Joined: 06 Mar 2004
Posts: 133
Location: Russia

Jin X 16 Dec 2020, 09:53

Thanks! But I want to do something if 'i' is defined, not undefined.

Of course, I can write

Code:

define i mov
i_defined equ 1
match =i,i { i_defined equ 0 }
if i_defined
  ;
end if

But it's too large code...

16 Dec 2020, 09:53

DimonSoft

Joined: 03 Mar 2010
Posts: 1228
Location: Belarus

DimonSoft 16 Dec 2020, 11:28

Code:

match =i , i { rept 0 \{ }
match ,
{
  display 'i is defined.'
}

16 Dec 2020, 11:28

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20343
Location: In your JS exploiting you and your system

revolution 16 Dec 2020, 11:39

Code:

define i mov
match=i,i{rept 0{}match,{display 'i is defined'}

Edit: DimonSoft already posted similar.

16 Dec 2020, 11:39

DimonSoft

Joined: 03 Mar 2010
Posts: 1228
Location: Belarus

DimonSoft 16 Dec 2020, 22:41

In fact, if the case where something is not defined means an error, one might not need to care about making proper “else” “branch”:

Code:

match =i , i { 'Error!' }
display 'i is defined.'

16 Dec 2020, 22:41

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20343
Location: In your JS exploiting you and your system

revolution 17 Dec 2020, 04:49

Using irpv might suit better. It can also know of something is defined as itself. But it suffers from a problem of running multiple times if it is defined more than once.

Code:

define mov mov
irpv x,mov{display 'mov is defined'}

17 Dec 2020, 04:49

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