Create a set of layers from a CSV list

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;;; ============================================================================
;;; CXLAYSTD - Create a set of layers from a CSV list
;;; Version 1.0.0
;;; CADXChange LISP tools - https://cadxchange.net/resources/lisp/cxlaystd
;;; Tested in: AutoCAD (full version). Other programs that run AutoLISP may work but are not tested.
;;; Copyright (c) CADXChange. Free for personal and commercial use; do not resell or
;;; republish it as a collection. Terms: https://cadxchange.net/legal/lisp-terms
;;; ============================================================================

;; Make or update layers from CSV rows (name, color number, linetype). The linetype is optional and is loaded
;; from the standard linetype file when the drawing does not have it yet.
;; Returns (created updated).
(defun cx:laystd-run (rows / created updated name color lt ed)
  (setq created 0 updated 0)
  (foreach r rows
    (setq name  (cx:trim (car r))
          color (if (and (cdr r) (> (strlen (cx:trim (cadr r))) 0)) (atoi (cadr r)) 7)
          lt    (if (and (cddr r) (> (strlen (cx:trim (caddr r))) 0)) (cx:trim (caddr r)) "Continuous"))
    (if (and (> (strlen name) 0) (not (cx:bad-name name)) (> color 0) (< color 256))
      (progn
        (if (not (tblsearch "LTYPE" lt))
          (command "_.-LINETYPE" "_L" lt "acad.lin" ""))
        (if (not (tblsearch "LTYPE" lt)) (setq lt "Continuous"))
        (if (setq ed (tblsearch "LAYER" name))
          (progn
            (cx:lay-set name 62 (if (< (cdr (assoc 62 ed)) 0) (- color) color))
            (cx:lay-set name 6 lt)
            (setq updated (1+ updated)))
          (progn
            (entmakex (list '(0 . "LAYER") '(100 . "AcDbSymbolTableRecord") '(100 . "AcDbLayerTableRecord")
                            (cons 2 name) '(70 . 0) (cons 62 color) (cons 6 lt)))
            (setq created (1+ created)))))))
  (list created updated))

(defun c:CXLAYSTD ( / *error* cx:sv file rows r)
  (setq *error* cx:err)
  (setq file (cx:file-open "Layer list (CSV: name, color number, linetype)"))
  (if file
    (if (setq rows (cx:csv-rows file))
      (progn
        ;; a header line such as "name,color,linetype" has no number in its second field
        (if (and rows (cdr (car rows)) (not (wcmatch (cx:trim (cadr (car rows))) "#*")))
          (setq rows (cdr rows)))
        (cx:start '(("CMDECHO" . 0)))
        (setq r (cx:laystd-run rows))
        (princ (strcat "\n" (itoa (car r)) " layer(s) created, " (itoa (cadr r)) " updated."))
        (cx:end))
      (princ "\nThe file could not be read.")))
  (princ))


;;; ---- Shared helpers (used by the command above; identical in every CADXChange tool) ----

;; Remove spaces and tabs at both ends.
(defun cx:trim (s / a b)
  (setq a 1 b (strlen s))
  (while (and (<= a b) (member (substr s a 1) '(" " "\t"))) (setq a (1+ a)))
  (while (and (>= b a) (member (substr s b 1) '(" " "\t"))) (setq b (1- b)))
  (substr s a (max 0 (1+ (- b a)))))

;; 1-based position of SUB in STR at or after START, or nil.
(defun cx:find (str sub start / n i r)
  (setq n (strlen sub) i start r nil)
  (if (> n 0)
    (while (and (not r) (<= i (1+ (- (strlen str) n))))
      (if (= (substr str i n) sub) (setq r i))
      (setq i (1+ i))))
  r)

;; True when STR holds a character that is not allowed in a layer, block or style name.
(defun cx:bad-name (str / bad)
  (foreach ch '("<" ">" "/" "\\" "\"" ":" ";" "?" "*" "|" "=" "`" ",")
    (if (cx:find str ch 1) (setq bad T)))
  bad)

;;; List helpers. See helpers.lsp for the format.

;; Set the DXF group CODE of layer NAME to VAL; returns T, or nil when there is no such layer.
(defun cx:lay-set (name code val / en ed)
  (if (setq en (tblobjname "LAYER" name))
    (progn
      (setq ed (entget en))
      (entmod (if (assoc code ed)
                (subst (cons code val) (assoc code ed) ed)
                (append ed (list (cons code val)))))
      T)))

;; Close the undo step and put the system variables back.
(defun cx:end ()
  (foreach v cx:sv (setvar (car v) (cdr v)))
  (command "_.UNDO" "_End")
  (setq cx:sv nil)
  (princ))

;; Error handler: restores everything, stays quiet on Esc.
(defun cx:err (msg)
  (if (> (getvar "CMDACTIVE") 0) (command))
  (cx:end)
  (if (and msg (not (wcmatch (strcase msg) "*BREAK*,*CANCEL*,*EXIT*")))
    (princ (strcat "\nError: " msg)))
  (princ))

;; Ask which CSV file to read. Returns a path or nil. With FILEDIA 0 the name is typed at the command line.
(defun cx:file-open (title / f)
  (if (= (getvar "FILEDIA") 0)
    (progn
      (setq f (getstring T (strcat "\n" title ": ")))
      (if (= f "") nil f))
    (getfiled title (getvar "DWGPREFIX") "csv" 4)))

;; All lines of a text file, or nil when it cannot be opened.
(defun cx:read-lines (file / f l out)
  (if (setq f (open file "r"))
    (progn
      (while (setq l (read-line f)) (setq out (cons l out)))
      (close f)
      (reverse out))))

;; One CSV line to a list of strings (handles quotes and doubled quotes).
(defun cx:csv-parse (line / out cur q i c)
  (setq out nil cur "" q nil i 1)
  (while (<= i (strlen line))
    (setq c (substr line i 1))
    (cond
      ((and q (= c "\"") (= (substr line (1+ i) 1) "\""))
       (setq cur (strcat cur "\"") i (1+ i)))
      ((= c "\"") (setq q (not q)))
      ((and (= c ",") (not q)) (setq out (cons cur out) cur ""))
      (T (setq cur (strcat cur c))))
    (setq i (1+ i)))
  (reverse (cons cur out)))

;; The rows of a CSV file as lists of strings, empty lines skipped; nil when the file cannot be read.
(defun cx:csv-rows (file / out)
  (foreach l (cx:read-lines file)
    (if (/= (cx:trim l) "") (setq out (cons (cx:csv-parse l) out))))
  (reverse out))

;; Save the system variables in VARS ((name . value) ...), set them, and open one undo step.
;; The caller declares cx:sv as a local so the saved values live exactly as long as the command.
(defun cx:start (vars)
  (setq cx:sv (mapcar (function (lambda (v) (cons (car v) (getvar (car v))))) vars))
  (command "_.UNDO" "_Begin")
  (foreach v vars (setvar (car v) (cdr v)))
  (princ))

(princ "\nCXLAYSTD loaded. Type CXLAYSTD to start.")
(princ)

More commands: Layers

• CXLAYISOIsolate the layers of the objects you pick
• CXLAYRESBring back the layers CXLAYISO switched off
• CXLAYOFFSwitch off the layers of the objects you pick
• CXLAYCOLORChange the color of the layers you pick
• CXLAYRENRename layers by find and replace
• CXLAYSETMove objects to the layer of another object
• CXLAYMRGMerge layers into one and delete the rest
• CXLAYCOUNTCount the objects on each layer
• CXLAYSELSelect everything on the layers you pick