From d5e155998d9c0dcd54d69491162f96c5bf188198 Mon Sep 17 00:00:00 2001
From: JSDurand <mmemmew@gmail.com>
Date: Tue, 21 Feb 2023 16:23:23 +0800
Subject: eshell: graphviz files management

Handle compilation and removal of graphviz files easily.

* .gitignore: Ignore elpa files that appear out of thin air.

* eshell-conf.el (eshell/gv): Entry point for handling graphviz files.

(vc): Use vc to find the project root.

(eshell-gv): The internal function to handle graphviz files.
---
 .gitignore     |  1 +
 eshell-conf.el | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 63 insertions(+)

diff --git a/.gitignore b/.gitignore
index 648dea0..f99fcfd 100644
--- a/.gitignore
+++ b/.gitignore
@@ -25,3 +25,4 @@ projects
 tramp
 calc.el
 multisession/*
+elpa/*
\ No newline at end of file
diff --git a/eshell-conf.el b/eshell-conf.el
index 42b727d..ba14746 100644
--- a/eshell-conf.el
+++ b/eshell-conf.el
@@ -560,5 +560,67 @@ For example, \"...\" expands into \"../..\"."
             :override
             #'durand-eshell-bookmark-jump)
 
+;;; Handle graphviz commands
+
+;; It is convenient to be able to compile multiple GraphViz files or
+;; delete multiple image files simultaneously.
+
+(defun eshell/gv (&rest args)
+  "Compile GraphViz files into images, or delete images, depending \
+on `args'."
+  (eshell-eval-using-options
+   "gv" args
+   '((?h "help" nil nil "Print this help message")
+     (?f "format" t image-format "Which image format to output")
+     (?r "remove" nil removep "Whether to remove images or not")
+     (?R "remove-all" nil remove-allp "Whether to remove images and sources or not")
+     :usage "[-f format] [-r|-R] [graphviz file names...]
+This little command can perform two tasks:
+
+- Compile multiple GraphViz files.
+- Remove output image files.
+
+The file names should not include any extension."
+     :preserve-args
+     :parse-leading-options-only
+     :show-usage)
+   (let ((removep (cond (remove-allp 'all) (removep))))
+     (eshell-gv image-format removep args))))
+
+(require 'vc)
+
+(defun eshell-gv (image-format removep &rest args)
+  "Internal function for `eshell/gv'."
+  (let ((args (car args))
+        (image-format (cond (image-format) ("png")))
+        (root-dir (expand-file-name "output" (vc-root-dir))))
+    (cond
+     (removep
+      (mapc
+       (lambda (arg)
+         (let* ((file-name (expand-file-name
+                            (format "%s.%s" arg image-format)))
+                (source-file-name (format "%s.gv" arg))
+                (source-file-name
+                 (expand-file-name source-file-name root-dir)))
+           (delete-file file-name)
+           (cond
+            ((eq removep 'all) (delete-file source-file-name)))))
+       args))
+     ((mapc
+       (lambda (arg)
+         (let* ((out-file-name (format "%s.%s" arg image-format))
+                (source-file-name (format "%s.gv" arg))
+                (source-file-name
+                 (expand-file-name source-file-name root-dir)))
+           (eshell-command-result
+            (format
+             "dot -T%s \"%s\" -o \"%s\""
+             image-format
+             source-file-name
+             out-file-name))))
+       args))))
+  nil)
+
 (provide 'eshell-conf)
 ;;; eshell-conf.el ends here
-- 
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