Merge pull request #1684 from SequentialDesign/add-line-number-format…

…-and-current-line-value-editor-vatriables-to-line-numbers

add two editor variables to line-numbers, line-number-format and current-line-value

src/ext/line-numbers.lisp

@@ -1,6 +1,8 @@
 (defpackage :lem/line-numbers
   (:use :cl :lem)
   (:export :*relative-line*
+           :line-number-format
+           :custom-current-line
            :line-numbers-attribute
            :active-line-number-attribute
            :line-numbers
@@ -15,13 +17,21 @@
 (defvar *previous-relative-line* nil)
 
 (defvar *initialized* nil)
-(defvar *line-number-format* nil)
+
+(define-editor-variable line-number-format "~6D "
+  "Set to desired format, for example, \"~2D \" for a
+two-character line-number column and a margin of one space.")
+
+(define-editor-variable custom-current-line nil
+  "Set to desired current-line value when relative line
+numbers are active, for example, \"->\".  NIL will make
+the absolute value of the current line display.")
 
 (define-attribute line-numbers-attribute
-    (t :foreground :base07 :background :base01))
+  (t :foreground :base07 :background :base01))
 
 (define-attribute active-line-number-attribute
-    (t :foreground :base07 :background :base01))
+  (t :foreground :base07 :background :base01))
 
 (define-editor-variable line-numbers nil ""
   (lambda (value)
@@ -46,16 +56,19 @@ With a positive universal argument, use relative line numbers. Also obey the glo
 
 (defun compute-line (buffer point)
   (if *relative-line*
-      (let* ((cursor-line (line-number-at-point (buffer-point buffer)))
-             (line (line-number-at-point point)))
+      (let ((cursor-line (line-number-at-point (buffer-point buffer)))
+            (line (line-number-at-point point))
+            (custom-line (variable-value 'custom-current-line :default buffer)))
         (if (= cursor-line line)
-            line
+            (if custom-line
+                custom-line
+                line)
             (abs (- cursor-line line))))
       (line-number-at-point point)))
 
 (defmethod lem-core:compute-left-display-area-content ((mode line-numbers-mode) buffer point)
   (when (buffer-filename (point-buffer point))
-    (let* ((string (format nil "~6D " (compute-line buffer point)))
+    (let* ((string (format nil (variable-value 'line-number-format :default buffer) (compute-line buffer point)))
            (attribute (if (eq (compute-line buffer point)
                               (compute-line buffer (buffer-point buffer)))
                           `((0 ,(length string) active-line-number-attribute))