From 0fb0c86b40e0189040534a9cfe416aeb1d8beb3b Mon Sep 17 00:00:00 2001
From: Christian Koestlin <christian.koestlin@gmail.com>
Date: Tue, 8 Mar 2022 23:12:31 +0100
Subject: [PATCH] lisp/ob-C.el: Support dub dependencies for dlang

Dlangs official package manager dub (https://dub.pm/) supports running
single files that carry dependency information in a /+ dub.sdl comment
block.

This patch switches from rdmd to dub if dependencies are used in the
source block. The dependency format used in the sourceblocks is
`:dependencies '(dep1=v1 ...)`.
The version specifier can be left out or be used with `*` which then
resolves to the latest version of the package.

Example:
#+begin_src D :dependencies '(mir-algorithm=*)
import mir.combinatorics;
import mir.ndslice.fuse;
foreach (permutation; ['a', 'b', 'c'].permutations) {
  writeln(permutation);
}
#+end_src

TINYCHANGE
---
 lisp/ob-C.el | 27 ++++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/lisp/ob-C.el b/lisp/ob-C.el
index 4f71a8879..55d2cb6d4 100644
--- a/lisp/ob-C.el
+++ b/lisp/ob-C.el
@@ -85,6 +85,15 @@ parameter may be used, like rdmd --chatty"
   :version "24.3"
   :type 'string)
 
+(defcustom org-babel-D-dub "dub"
+  "Command of the dlang package manager dub.
+May be either a command in the path, like dub
+or an absolute path name, like /usr/local/bin/dub
+parameter may be used, like dub --verbose"
+  :group 'org-babel
+  :version "24.3"
+  :type 'string)
+
 (defvar org-babel-c-variant nil
   "Internal variable used to hold which type of C (e.g. C or C++ or D)
 is currently being evaluated.")
@@ -173,7 +182,9 @@ or `org-babel-execute:C++' or `org-babel-execute:D'."
 	       (concat tmp-bin-file cmdline))
 	      (`d
 	       (format "%s %s %s %s"
-		       org-babel-D-compiler
+		       (pcase (cdr (assq :dependencies params))
+                         ('nil org-babel-D-rdmd)
+                         (_ org-babel-D-dub))
 		       flags
 		       (org-babel-process-file-name tmp-src-file)
 		       cmdline)))
@@ -265,11 +276,22 @@ or `org-babel-execute:C++' or `org-babel-execute:D'."
 		    (org-babel-C-ensure-main-wrap body)
 		  body) "\n") "\n")))
 
+(defun org-babel-D-dependencies (dependencies)
+  "Convert DEPENDENCIES to dub.sdl code."
+  (mapconcat
+   (lambda (x) (let* (
+                      (s (split-string (symbol-name x) "="))
+                      (d (car s))
+                      (v (or (car (cdr s)) "*")))
+                 (format "dependency \"%s\" version=\"%s\"" d v)))
+   dependencies "\n"))
+
 (defun org-babel-C-expand-D (body params)
   "Expand a block of D code with org-babel according to its header arguments."
   (let ((vars (org-babel--get-vars params))
 	(colnames (cdr (assq :colname-names params)))
 	(main-p (not (string= (cdr (assq :main params)) "no")))
+	(dependencies (cdr (assq :dependencies params)))
 	(imports (or (cdr (assq :imports params))
 		     (org-babel-read (org-entry-get nil "imports" t)))))
     (when (stringp imports)
@@ -277,6 +299,9 @@ or `org-babel-execute:C++' or `org-babel-execute:D'."
     (setq imports (append imports '("std.stdio" "std.conv")))
     (mapconcat 'identity
 	       (list
+		"/+ dub.sdl:"
+		(org-babel-D-dependencies dependencies)
+		"+/"
 		"module mmm;"
 		;; imports
 		(mapconcat
-- 
2.33.1