Help with Diesel Expression

[CivilTechSource]

I am trying to write a diesel expression that will extract the first part of the drawing file name. 

Full Drawing File Name: XXX-ZINC-XX-XX-DR-C-01000_S278 Sections

First Part:  XXX-ZINC-XX-XX-DR-C-

My question: Is there a smarter way to extract the first part rather than relaying on the number of characters? If everyone is following the correct naming protocol it would be 20 characters but sometimes you have people instead of -C- they put -CE- so I am wondering is there a way to future proof it.

 

Thank you.

 

$(substr,$(getvar,"dwgname"),1,20)

 

[BIGAL]

One of the others ways to do this is to use a lisp and break the string into individual bits. As you have a "-" as a common item in the string you can blow it apart and rejoin. Thanks to Lee-mac parse lsp. Something like this.

; Parse string to a list ny Lee-mac

(defun csv->lst (str ans / pos )
(if (setq pos (vl-string-position ans str))
    (cons (substr str 1 pos) (csv->lst (substr str (+ pos 2)) ans))
    (list str)
    )
)

(setq str "XXX-ZINC-XX-XX-DR-C-01000_S278 Sections") ; use (getvar 'dwgname)
(setq newstr "" x 0)
(setq ans (csv->lst str 45))
(repeat (- (length ans) 2)
(setq newstr (strcat newstr (nth x ans) "-"))
(setq x (1+ x))
)
(setq newstr (strcat newstr (nth x ans)))

 

Ps ; tab 9 space 32 (chr 32) comma 44 semicolon 59 slash / 47 - 45

[CivilTechSource]

Thank you so much! After playing with lisp for over a two months now I am so happy that I can understand the above!