From b3dbcc39ab119162a9a0c5a172a33f6367a13845 Mon Sep 17 00:00:00 2001
From: Bruno BARBIER <brubar.cs@gmail.com>
Date: Sat, 25 Mar 2023 10:06:44 +0100
Subject: [PATCH 6/7] ob-haskell: Implement sessions

* lisp/ob-haskell.el (org-babel-haskell-initiate-session): Implement
sessions.

* testing/lisp/test-ob-haskell-ghci.el: Update tests related to
sessions.
---
 lisp/ob-haskell.el                   | 50 +++++++++++++++++++++-------
 testing/lisp/test-ob-haskell-ghci.el |  8 +++--
 2 files changed, 44 insertions(+), 14 deletions(-)

diff --git a/lisp/ob-haskell.el b/lisp/ob-haskell.el
index a8a8df9d8..f7acb1011 100644
--- a/lisp/ob-haskell.el
+++ b/lisp/ob-haskell.el
@@ -51,6 +51,8 @@ (declare-function haskell-mode "ext:haskell-mode" ())
 (declare-function run-haskell "ext:inf-haskell" (&optional arg))
 (declare-function inferior-haskell-load-file
 		  "ext:inf-haskell" (&optional reload))
+(declare-function inferior-haskell-start-process
+                  "ext:inf-haskell" ())
 (declare-function org-entry-get "org" (pom property &optional inherit literal-nil))
 
 (defvar org-babel-tangle-lang-exts)
@@ -183,20 +185,44 @@ (defun org-babel-execute:haskell (body params)
 	(org-babel-interpret-haskell body params)
       (org-babel-haskell-execute body params))))
 
-(defun org-babel-haskell-initiate-session (&optional _session _params)
+
+
+
+;; Variable defined in inf-haskell (haskell-mode package).
+(defvar inferior-haskell-buffer)
+
+(defun org-babel-haskell-initiate-session (&optional session-name _params)
   "Initiate a haskell session.
-If there is not a current inferior-process-buffer in SESSION
-then create one.  Return the initialized session."
+Return the initialized session."
   (org-require-package 'inf-haskell "haskell-mode")
-  (or (get-buffer "*haskell*")
-      (save-window-excursion
-        (run-haskell)
-        (sleep-for 0.25)
-        ;; Disable secondary prompt.
-        (org-babel-comint-input-command
-         (current-buffer)
-         ":set prompt-cont \"\"")
-        (current-buffer))))
+  (when (and session-name (string= session-name "none"))
+    (setq session-name nil))
+  (unless session-name
+    ;; As haskell-mode is using the buffer name "*haskell*", we stay
+    ;; away from it.
+    (setq session-name (generate-new-buffer-name "*ob-haskell*")))
+  (let ((session (get-buffer session-name)))
+    (save-window-excursion
+      (or (org-babel-comint-buffer-livep session)
+          (let ((inferior-haskell-buffer session))
+            (when (and (bufferp session) (not (org-babel-comint-buffer-livep session)))
+              (when (bufferp "*haskell*") (error "Conflicting buffer '*haskell*', rename it or kill it."))
+              (with-current-buffer session (rename-buffer "*haskell*")))
+            (save-window-excursion
+              ;; We don't use `run-haskell' to not popup the buffer.
+              ;; And we protect default-directory.
+              (let ((default-directory default-directory))
+                (inferior-haskell-start-process))
+              (sleep-for 0.25)
+              (setq session inferior-haskell-buffer)
+              (with-current-buffer session (rename-buffer session-name))
+              ;; Disable secondary prompt.
+              (org-babel-comint-input-command
+               session
+               ":set prompt-cont \"\"")
+              session))))
+    session))
+
 
 (defun org-babel-load-session:haskell (session body params)
   "Load BODY into SESSION."
diff --git a/testing/lisp/test-ob-haskell-ghci.el b/testing/lisp/test-ob-haskell-ghci.el
index 2ddfb4de7..907487960 100644
--- a/testing/lisp/test-ob-haskell-ghci.el
+++ b/testing/lisp/test-ob-haskell-ghci.el
@@ -133,7 +133,6 @@ (ert-deftest ob-haskell/hello-world-output-multilines ()
 
 (ert-deftest ob-haskell/sessions-must-not-share-variables ()
   "Sessions must not share variables."
-  :expected-result :failed
   (test-ob-haskell-ghci-with-global-session
    (test-ob-haskell-ghci ":session s1" "x=2" nil :unprotected)
    (should (equal 2 (test-ob-haskell-ghci ":session s1" "x" nil :unprotected)))
@@ -143,11 +142,16 @@ (ert-deftest ob-haskell/sessions-must-not-share-variables ()
 
 (ert-deftest ob-haskell/no-session-means-one-shot-sessions ()
   "When no session, use a new session."
-  :expected-result :failed
   (test-ob-haskell-ghci-with-global-session
    (test-ob-haskell-ghci "" "x=2" nil :unprotected)
    (should-not (equal 2 (test-ob-haskell-ghci "" "x" nil :unprotected)))))
 
+(ert-deftest ob-haskell/reuse-variables-in-same-session ()
+  "Reuse variables between blocks using the same session."
+  (test-ob-haskell-ghci ":session s1" "x=2" nil)
+  (should (equal 2 (test-ob-haskell-ghci ":session s1" "x"))))
+
+
 
 ;;;; Values
 ;;
-- 
2.39.1