Topic: Maybe I'm just thick - Cond question...

[bruno_vdh]

OK, maybe I'm just thick. Is one of these 2 snippets correct? Are they the same? 

#1 can be written with or, while #2 can only be constructed with cond, if that helps your thinking...

[ronjonp]

For me a simpler way to read the cond

Code: [Select]

     (cond
             ((wcmatch txt1 "UPD Not Found"))(setq txt TXT1))
             ((wcmatch txt2 "UPD Not Found"))(setq txt TXT2))
             ((null FULL))(setq txt full)
             ((setq txt "NO TAG#"))
     );;_end cond

"Unbalanced closing brackets."

Also .. you can pull the (setq txt outside of the COND and only return the values.

[BIGAL]

Thanks ronjonp just typed did not check

Code: [Select]

(cond
             ((wcmatch txt1 "UPD Not Found")(setq txt TXT1))
             ((wcmatch txt2 "UPD Not Found")(setq txt TXT2))
             ((null FULL)(setq txt full))
             ((setq txt "NO TAG#"))
     );;_end cond

[steve.carson]

I know when I first started using cond, I always got tripped up by the parenthesis so I would type something like this first, just to keep things straight in my head:

Code - Auto/Visual Lisp: [Select]

1. (cond
2.     ((         ) ;<-- First test
3.         (          ) ;<-- Do this
4.         (          ) ;<-- And this
5.     )
6.     ((         ) ;<-- Second test
7.         (          ) ;<-- Do this
8.         (          ) ;<-- And this
9.     )
10.     ((         ) ;<-- Third test
11.         (          ) ;<-- Do this
12.         (          ) ;<-- And this
13.     )
14. ); cond
15.  

And then go back and start filling it in with what I want it to do.

[CHulse]

This is what I eventually ended up with (and is working nicely).
Thanks to everyone for the help with this.

Code - Auto/Visual Lisp: [Select]

1.                         (setq TXT
2.                                 (cond
3.                                         ((not(or (wcmatch TAG1 "UPD Not Found,0,")(null TAG1))) ;;check if UDP not found, empty string, 0, or null
4.                                                 TAG1
5.                                         )
6.                                         ((not(or(wcmatch TAG2 "UPD Not Found,0,")(null TAG2)))
7.                                                 TAG2
8.                                         )
9.                                         ((not(or(wcmatch FULL "0,")(null FULL) ))  
10.                                                 FULL
11.                                         )      
12.                                         ( T
13.                                                 "NO TAG#"
14.                                         )
15.                                 );;_end cond   
16.                         );;_end setq
17.  

[bruno_vdh]

Hi,

This is what I eventually ended up with (and is working nicely).

Just a small note, it is better to check if the variable is null first:

Code: [Select]

_$ (setq TAG1 nil)
nil
_$ (not (or (wcmatch TAG1 "UPD Not Found,0,") (null TAG1)))
; erreur: type d'argument incorrect: stringp nil
_$ (not (or (null TAG1) (wcmatch TAG1 "UPD Not Found,0,")))
nil

[bruno_vdh]

Just a small note, it is better to check if the variable is null first:

Code: [Select]

_$ (setq TAG1 nil)
nil
_$ (not (or (wcmatch TAG1 "UPD Not Found,0,") (null TAG1)))
; erreur: type d'argument incorrect: stringp nil
_$ (not (or (null TAG1) (wcmatch TAG1 "UPD Not Found,0,")))
nil

To avoid type errors, you can also use the member function as a predicate

Code - Auto/Visual Lisp: [Select]

1. (not (member TAG1 '("UPD Not Found" "0" "" nil)))