Simple arl-mode plugin for Emacs

arl.org

@@ -1,5 +1,6 @@
 #+title: ARL - Issue tracker
 #+date: 2026-01-23
+#+filetags: arl
 
 * TODO Write a minimum working transpiler
 We need to be able to compile the following file:
@@ -23,13 +24,13 @@ It's a Eulerian Path from the source code to the native executable.
 [[file:src/parser/]]
 [[file:include/arl/parser/]]
 
-We need to generate some form of AST from the token stream.  We want
-something a stage above the tokeniser so it should distinguish the
-following cases:
-- Literal value
-- Primitive call
-*** TODO AST design
-*** TODO Token Stream to AST implementation
+We need to generate some form of AST from the token stream.  This
+should be a little more advanced than our initial stream,
+distinguishing between
+- Literal values
+- Primitive calls
+- References to otherwise undefined words (may be defined through
+  import or later on)
 ** TODO Stack effect/type analysis
 [[file:src/analysis/]]
 [[file:include/arl/analysis/]]

examples/hello-world.arl

@@ -1 +1 @@
-"Hello, world!\n" putstr
+"Hello, world!\n" puts

extensions/arl-mode.el

@@ -0,0 +1,37 @@
+;;; arl-mode.el --- ARL mode for Emacs               -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2026  Aryadev Chavali
+
+;; Author: Aryadev Chavali <aryadev@aryadevchavali.com>
+;; Keywords:
+
+;; Copyright (C) 2026 Aryadev Chavali
+
+;; This program is distributed in the hope that it will be useful, but WITHOUT
+;; ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+;; FOR A PARTICULAR PURPOSE.  See the MIT License for details.
+
+;; You may distribute and modify this code under the terms of the MIT License,
+;; which you should have received a copy of along with this program.  If not,
+;; please go to <https://opensource.org/license/MIT>.
+
+;;; Commentary:
+
+;;
+
+;;; Code:
+
+(defvar arl-mode-comments '(?\; ";;" ("#|" . "|#")))
+(defvar arl-mode-keywords '("if" "then" "else"))
+(defvar arl-mode-expressions '(("\".*\"" . font-lock-string-face)))
+(defvar arl-mode-automode-list '("\\.arl"))
+
+(define-derived-mode arl-mode
+  arl-mode-comments
+  arl-mode-keywords
+  arl-mode-expressions
+  arl-mode-automode-list
+  nil)
+
+(provide 'arl-mode)
+;;; arl-mode.el ends here

include/arl/lexer/token.h

@@ -25,7 +25,7 @@ typedef enum
 /// Known symbols which later stages would benefit from.
 typedef enum
 {
-  TOKEN_KNOWN_PUTSTR,
+  TOKEN_KNOWN_PUTS,
   NUM_TOKEN_KNOWNS,
 } token_known_t;
 

src/lexer/token.c

@@ -13,8 +13,8 @@ const char *token_known_to_cstr(token_known_t known)
 {
   switch (known)
   {
-  case TOKEN_KNOWN_PUTSTR:
-    return "putstr";
+  case TOKEN_KNOWN_PUTS:
+    return "puts";
   default:
     FAIL("Unexpected TOKEN_KNOWN value: %d\n", known);
   }