Draft version of basic superbol-mode for GNU/Emacs

.drom

@@ -5,7 +5,7 @@ version:0.9.0
 
 # hash of toml configuration files
 # used for generation of all files
-ce91e02d93482e19b68ff8b123bea8a3:.
+8288a3cd2b32b2fada49d59ebfc4d900:.
 # end context for .
 
 # begin context for .github/workflows/workflow.yml
@@ -15,7 +15,7 @@ fc10b0887fb072e04e5bcbdd5a0c6668:.github/workflows/workflow.yml
 
 # begin context for .gitignore
 # file .gitignore
-90b1808274a081597c6ff82400928561:.gitignore
+0727863b8e681aec0cc8d969f8cfb747:.gitignore
 # end context for .gitignore
 
 # begin context for CHANGES.md
@@ -30,7 +30,7 @@ d00f73c835ae4a1589d55ebda4ab381b:CHANGES.md
 
 # begin context for Makefile
 # file Makefile
-86f0208a874473207a92c1e552fa9cb5:Makefile
+8c1798510e3d14cdfd80b0ebd931773b:Makefile
 # end context for Makefile
 
 # begin context for README.md

.gitignore

@@ -28,5 +28,6 @@ ATTIC
 !.vscode/launch.json
 *.vsix
 *.opam.locked
+/emacs/lsp-superbol-customs.el
 
 

Makefile.header

@@ -1,6 +1,11 @@
+# -*- Makefile -*-
 PROJECT=superbol_vscode_platform
 SRCDIR=src/vscode/superbol-vscode-platform
 
+# Emacs lsp-mode source directory (https://github.com/emacs-lsp/lsp-mode):
+# (could be a submodule)
+LSP_MODE_SRCDIR ?= ../lsp-mode
+
 .PHONY: compile
 compile: build
 	cp -f _build/default/src/vscode/vscode-package-json/main.exe vscode-package-json
@@ -33,3 +38,14 @@ opam-cross:
 	drom dep --cross osx
 	drom dep --cross windows
 
+# emacs-lsp:
+emacs/lsp-superbol-customs.el: $(LSP_MODE_SRCDIR) package.json
+	emacs --batch > "$@" \
+	      --load "$(LSP_MODE_SRCDIR)/scripts/lsp-generate-settings.el" \
+	      --eval "(dolist (l (lsp-generate-settings \"package.json\")) (print l))" \
+	  && echo "Generated $@" 1>&2 \
+	  || rm -f "$@"
+
+# 8.0.1
+# --eval "(princ (lsp-generate-settings \"package.json\" 'lsp-superbol))" \
+# --eval '(princ "\n")' \

README.md

@@ -1,16 +1,20 @@
-# Superbol VSCode Platform for COBOL
+# Superbol Studio OSS: A New Platform for COBOL
 
 ## Features
 
-* LSP (superbol) with following capabilities:
+* LSP (`superbol-free`) with following capabilities:
     * Syntax diagnostics
     * Go to definitions
     * Find references
-    * Peek on copybook (Superbol PR #211)
-    * Semantic highlighting (Superbol PR #212)
+    * Peek on copybook and source text replacements
+    * Semantic highlighting
     * File and range indentation
 
-## Install
+* VSCode extension
+
+* GNU/Emacs mode
+
+## VSCode Extension
 
 ### From binary and VSIX
 
@@ -65,6 +69,10 @@ In the `superbol` field past the path to the `superbol` executable.
 
 You can check the documentation on using the extension on [this page](https://ocamlpro.github.io/superbol-vscode-platform/sphinx).
 
+## GNU/Emacs mode
+
+You can check the documentation on using the Superbol LSP with GNU/Emacs on [this page](https://ocamlpro.github.io/superbol-vscode-platform/sphinx/emacs.html).
+
 ## Resources
 
 * Website: https://ocamlpro.github.io/superbol-vscode-platform

drom.toml

@@ -87,6 +87,7 @@ ATTIC
 !.vscode/launch.json
 *.vsix
 *.opam.locked
+/emacs/lsp-superbol-customs.el
 """
 github-workflow-before-build = """
 

emacs/eglot-superbol.el

@@ -0,0 +1,42 @@
+;;; lsp-superbol.el --- Eglot LSP client for Superbol COBOL -*- lexical-binding: t; -*-
+;;
+;;  Copyright (c) 2023 OCamlPro SAS
+;;
+;;  All rights reserved.
+;;  This source code is licensed under the MIT license found in the
+;;  LICENSE.md file in the root directory of this source tree.
+
+;;; Commentary:
+
+;; Eglot LSP client for Superbol COBOL
+
+;;; Code:
+
+(unless (fboundp 'eglot)
+  (load "eglot-autoloads"))
+
+(require 'eglot)
+(require 'superbol-mode)
+
+(defun eglot-superbol--start ()
+  "Superbol LSP startup function for Eglot"
+
+  ;; Actually start the LSP server
+  (eglot-ensure)
+
+  ;; Turn on fontification (even if minimal)
+  (funcall font-lock-fontify-buffer-function))
+
+(add-to-list 'eglot-server-programs '(superbol-mode . ("superbol-free" "lsp")))
+(add-to-list 'eglot-server-programs '(cobol-mode    . ("superbol-free" "lsp")))
+
+;; Autostart the LSP when entering superbol-mode
+(add-hook 'superbol-mode-hook #'eglot-superbol--start)
+
+;; Also load on cobol-mode
+(with-eval-after-load 'cobol-mode
+  (add-hook 'cobol-mode-hook #'eglot-superbol--start))
+
+(provide 'eglot-superbol)
+
+;;; eglot-superbol.el ends here

emacs/lsp-superbol.el

@@ -0,0 +1,82 @@
+;;; lsp-superbol.el --- lsp-mode LSP client for Superbol COBOL -*- lexical-binding: t; -*-
+;;
+;;  Copyright (c) 2023 OCamlPro SAS
+;;
+;;  All rights reserved.
+;;  This source code is licensed under the MIT license found in the
+;;  LICENSE.md file in the root directory of this source tree.
+
+;;; Commentary:
+
+;; lsp-mode.el LSP client for Superbol COBOL
+
+;;; Code:
+
+(unless (fboundp 'lsp-mode)
+  (load "lsp-mode-autoloads"))
+
+(require 'lsp-mode)
+(require 'superbol-mode)
+
+;; ---
+
+(defgroup lsp-superbol nil
+  "Settings for the Superbol Language Server for COBOL (lsp-mode)."
+  :group 'lsp-mode
+  :link '(url-link "https://github.com/OCamlPro/superbol-vscode-extension")
+  :package-version '(lsp-mode . "8.0.1"))
+
+(load (expand-file-name "lsp-superbol-customs.el"
+			(file-name-directory load-file-name)))
+
+;; ---
+
+(defun lsp-superbol--server-command ()
+  "Startup command for the Superbol LSP language server."
+  ;; (list (lsp-package-path 'superbol-language-server) "lsp"))
+  (list (expand-file-name "superbol-free" lsp-superbol-path) "lsp"))
+
+;; (lsp-dependency 'superbol-language-server
+;; 		`(:system ,(executable-find (lsp-package-path 'superbol-language-server))))
+;; '(:system "superbol-language-server"))
+
+(lsp-register-client
+ (make-lsp-client
+  :new-connection (lsp-stdio-connection #'lsp-superbol--server-command)
+  :priority 0
+  :activation-fn (lsp-activate-on "superbol" "cobol" "COBOL")
+  :server-id 'superbol-ls
+  ))
+
+;; ---
+
+;; (with-eval-after-load 'superbol-mode
+(add-to-list 'lsp-language-id-configuration '(superbol-mode . "cobol"))
+(add-to-list 'lsp-language-id-configuration '(cobol-mode    . "cobol"))
+
+(defun lsp-superbol--start ()
+  "Superbol LSP startup function for lsp-mode"
+
+  ;; Enable semantic tokens
+  (set (make-local-variable 'lsp-semantic-tokens-enable) t)
+
+  ;; Actually start the LSP server
+  (lsp)
+
+  ;; Turn on fontification
+  (funcall font-lock-fontify-buffer-function))
+
+;; Autostart the LSP when entering superbol-mode
+(add-hook 'superbol-mode-hook #'lsp-superbol--start)
+
+;; Also load on cobol-mode
+(with-eval-after-load 'cobol-mode
+  (add-hook 'cobol-mode-hook #'lsp-superbol--start))
+
+;; ---
+
+(lsp-consistency-check lsp-superbol)
+
+(provide 'lsp-superbol)
+
+;;; lsp-superbol.el ends here

emacs/superbol-mode.el

@@ -0,0 +1,40 @@
+;;; superbol-mode.el --- Superbol COBOL major mode -*- lexical-binding: t; -*-
+;;
+;;  Copyright (c) 2023 OCamlPro SAS
+;;
+;;  All rights reserved.
+;;  This source code is licensed under the MIT license found in the
+;;  LICENSE.md file in the root directory of this source tree.
+
+;;; Commentary:
+
+;; Major mode for editing COBOL files using Superbol as a LSP server
+
+;;; Code:
+
+;; CHECKME: Force association right here?
+(defun superbol-mode-enable-for-default-extensions ()
+  "Automatically associate `superbol-mode` with a few common COBOL file
+extensions."
+  (dolist (regex '("\\.[cC][oO][bB]\\'"
+		   "\\.[cC][bB][lL]\\'"
+		   "\\.[cC][pP][yY]\\'"))
+    (add-to-list 'auto-mode-alist `(,regex . superbol-mode))))
+
+;;;###autoload
+(define-derived-mode superbol-mode prog-mode
+  "Superbol"
+  "SUPERBOL mode is a major mode for handling COBOL files.  It is mostly intended
+to be backed by an LSP."
+  ;; XXX: could actually derive from cobol-mode, if available.
+
+  ;; Straight from cobol-mode
+  (set (make-local-variable 'comment-start-skip)
+       "\\(^.\\{6\\}\\*\\|\\*>\\)\\s-* *")
+  (set (make-local-variable 'comment-start) "*>")
+  (set (make-local-variable 'comment-end) ""))
+
+;; ---
+
+(provide 'superbol-mode)
+;;; superbol-mode.el ends here

sphinx/emacs.rst

@@ -1,5 +1,11 @@
-Emacs modes
-===========
+GNU/Emacs modes
+===============
+
+We document two means that are available for editing COBOL files using
+GNU/Emacs.  One makes use of a modified version of
+:code:`cobol-mode.el` that can be found on ELPA.  The other is a new
+mode, :code:`superbol-mode`, that simply makes use of the LSP to
+provide a powerful COBOL IDE.
 
 Standard file :code:`cobol-mode.el`
 -----------------------------------
@@ -30,7 +36,7 @@ change this option using :code:`M-x customize`, save and then restart emacs.
 Features
 ~~~~~~~~
 
-The :code:`cobol-mode.el` provides a following features:
+The :code:`cobol-mode.el` provides the following features:
 
 * colorization
 * indentation
@@ -46,3 +52,86 @@ Customization
 We advise to also use the :code:`auto-complete` mode also. This mode
 will propose completions while typing keywords (use TAB or RET to
 complete).
+
+Superbol-mode
+-------------
+
+The new Superbol mode provides an IDE that makes use of the Superbol
+LSP to provide advanced navigation and editing facilities for COBOL
+projects.  It can be used in combination with any of the two main LSP
+clients that exist within the GNU/Emacs ecosystem to interact with LSP
+servers: `lsp-mode` and `eglot`.
+
+Superbol-mode with `lsp-mode`
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+`lsp-mode`_ appears to be the most prominent at the moment.  This
+client benefits from a large user-base, but is also considered
+"bloated" by some.
+
+The main advantages for using it in our context is its support for
+`semantic tokens`_, that provide a way for LSPs to issue information
+about the semantics of symbols from the source code.  Compared to
+traditional regexp-based highlighting, semantic tokens-based
+highlighting can drastically improve code readability of various
+source code elements based on their syntactic location;
+
+.. _lsp-mode: https://github.com/emacs-lsp/lsp-mode
+.. _semantic tokens:
+    https://code.visualstudio.com/api/language-extensions/semantic-highlight-guide
+
+
+Superbol-mode with `eglot`
+~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Another possibility is to use `eglot`_, that is sometimes considered
+easier to configure and more lightweight than `lsp-mode` (which
+notably makes it more reactive to user inputs).  Being more recent, it
+lacks some of the features of `lsp-mode`, among which is the support
+for semantic tokens [#eglot-semtok-issue]_.  However, additionally
+enabling the aforementioned `cobol-mode.el` provides reasonable syntax
+highlighting.
+
+.. _eglot: https://elpa.gnu.org/packages/eglot.html
+
+Setup
+~~~~~
+
+Let us first define an environment variable that indicates where the
+``superbol-free`` executable can be found.  Additionally, define a
+variable that points to the root of the source directory for the
+extension:
+
+.. code-block:: shell
+
+   export SUPERBOL_DIR="<directory where superbol-free can be found>";
+   export SUPERBOL_VSCODE_PLATFORM_DIR="$PWD";
+
+After this, the following command launches a GNU/Emacs instance with
+an `lsp-mode`-based client configured for COBOL files:
+
+.. code-block:: shell
+
+   emacs -L "$SUPERBOL_VSCODE_PLATFORM_DIR/emacs" \
+         --load lsp-superbol \
+         --eval "(custom-set-variables '(lsp-superbol-path \"$SUPERBOL_DIR\"))" \
+         --funcall superbol-mode-enable-for-default-extensions
+
+To use `eglot`, type the following instead:
+
+.. code-block:: shell
+
+   emacs -L "$SUPERBOL_VSCODE_PLATFORM_DIR/emacs" \
+         --load eglot-superbol \
+         --eval "(add-to-list 'exec-path \"$SUPERBOL_DIR\")" \
+         --funcall superbol-mode-enable-for-default-extensions
+
+Further configuration for auto-indentation:
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+`lsp-mode` provides a ``lsp-format-region`` function that may be used
+to use the LSP-provided intentation.  When using `eglot`, the same
+functionality is provided by ``eglot-format``.
+
+.. [#eglot-semtok-issue] Note there is a pending issue on this point
+   at https://github.com/joaotavora/eglot/issues/615 .