From e65276fb92a1e7a86d2ce894482eaf5c53b7a34e Mon Sep 17 00:00:00 2001
From: Gustaf Waldemarson <gustaf.waldemarson@gmail.com>
Date: Tue, 29 Nov 2022 23:40:23 +0100
Subject: [PATCH] gdb-mi.el: Configure variable order and length.

This changes allows users to configure the order of various properties
as well as truncating their length. The full description of each
property is available as a help-text (tooltip).
---
 etc/NEWS                 | 17 +++++++++++++
 lisp/progmodes/gdb-mi.el | 53 ++++++++++++++++++++++++++++++++--------
 2 files changed, 60 insertions(+), 10 deletions(-)

diff --git a/etc/NEWS b/etc/NEWS
index 9b8edde5155..473d427e757 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -40,6 +40,23 @@ connection.
 
 
 * Changes in Specialized Modes and Packages in Emacs 30.1
+---
+** Variable order and truncation can now be configured in gdb-many-window mode.
+The new variable `gdb-locals-table-row-config' allows users to
+configure the order and max length of various properties in the local
+variables frame.
+
+By default, this variable is set to write the properties in the order:
+name, type and value. Where name and type are truncated to 20
+characters, and the value is truncated to 100.
+
+In order to restore the old display behavior, set
+`gdb-locals-table-row-config' to '((type . 0)(name . 0)(value . 0)).
+
+Additionally, this behavior encompasses the actions of the old
+`gdb-locals-value-limit' variable, which is no longer used and marked
+deprecated.
+
 
 
 * New Modes and Packages in Emacs 30.1
diff --git a/lisp/progmodes/gdb-mi.el b/lisp/progmodes/gdb-mi.el
index e8d8f9104e4..80950fec77e 100644
--- a/lisp/progmodes/gdb-mi.el
+++ b/lisp/progmodes/gdb-mi.el
@@ -4355,6 +4355,24 @@ gdb-locals-value-limit
   :group 'gud
   :version "29.1")
 
+(defcustom gdb-locals-table-row-config '((name . 20)
+                                         (type . 20)
+                                         (value . 100))
+  "Configuration for table rows in the local variable display.
+
+An alist that controls the display of the name, type and value of
+local variables inside the currently active stack-frame.  The key
+controls which column to change whereas the value determines the
+maximum number of characters to display in each column.  A value
+of 0 means there is no limit.
+
+Additionally, the order the element in the alist determines the
+left-to-right display order of the properties."
+  :type '(alist :key-type 'symbol :value-type 'integer)
+  :group 'gud
+  :version "30.1")
+
+
 (defvar gdb-locals-values-table (make-hash-table :test #'equal)
   "Mapping of local variable names to a string with their value.")
 
@@ -4384,12 +4402,9 @@ gdb-edit-locals-map-1
 
 (defun gdb-locals-value-filter (value)
   "Filter function for the local variable VALUE."
-  (let* ((no-nl (replace-regexp-in-string "\n" " " value))
-         (str (replace-regexp-in-string "[[:space:]]+" " " no-nl))
-         (limit gdb-locals-value-limit))
-    (if (>= (length str) limit)
-        (concat (substring str 0 limit) "...")
-      str)))
+  (let* ((no-nl (replace-regexp-in-string "\n" " " (or value "<Unknown>")))
+         (str (replace-regexp-in-string "[[:space:]]+" " " no-nl)))
+    str))
 
 (defun gdb-edit-locals-value (&optional event)
   "Assign a value to a variable displayed in the locals buffer."
@@ -4403,6 +4418,22 @@ gdb-edit-locals-value
       (gud-basic-call
        (concat  "-gdb-set variable " var " = " value)))))
 
+
+(defun gdb-locals-table-columns-list (alist)
+  "Format and arrange the columns in locals display based on ALIST."
+  (let (columns)
+    (dolist (config gdb-locals-table-row-config columns)
+      (let* ((key  (car config))
+             (max  (cdr config))
+             (prop (alist-get key alist)))
+        (when prop
+          (if (and (> max 0) (length> prop max))
+              (push (propertize (string-truncate-left prop max) 'help-echo prop)
+                    columns)
+            (push prop columns)))))
+    (nreverse columns)))
+
+
 ;; Complex data types are looked up in `gdb-locals-values-table'.
 (defun gdb-locals-handler-custom ()
   "Handler to rebuild the local variables table buffer."
@@ -4431,12 +4462,14 @@ gdb-locals-handler-custom
                                             help-echo "mouse-2: edit value"
                                             local-map ,gdb-edit-locals-map-1)
                                value))
+        (setf (gdb-table-right-align table) t)
+        (setq name (propertize name 'font-lock-face font-lock-variable-name-face))
+        (setq type (propertize type 'font-lock-face font-lock-type-face))
         (gdb-table-add-row
          table
-         (list
-          (propertize type 'font-lock-face font-lock-type-face)
-          (propertize name 'font-lock-face font-lock-variable-name-face)
-          value)
+         (gdb-locals-table-columns-list `((name  . ,name)
+                                          (type  . ,type)
+                                          (value . ,value)))
          `(gdb-local-variable ,local))))
     (insert (gdb-table-string table " "))
     (setq mode-name
-- 
2.34.1