add syntax highlighting for emacs

Signed-off-by: Ava Hahn <ava@sunnypup.io>

Readme.org

@@ -80,6 +80,13 @@ Variables and functions defined in an external script loaded by your interpreter
   (call "my-extra-library-functions.rls")
 #+END_SRC
 
+* Syntax Highlighting
+Syntax Highlighting is implemented for Emacs under [[file:snippets/relish-mode.el][the Relish Mode module (snippets/relish-mode.el)]].
+For installation, consider adding the following to your ~\~/.emacs~:
+#+BEGIN_SRC el
+  (load-file "/PATH/TO/relish/snippets/relish-mode.el")
+#+END_SRC
+
 * Compilation
 Compiling Relish is as simple as kicking off a build with Cargo.
 #+BEGIN_EXAMPLE sh
@@ -162,6 +169,7 @@ Note: this section only tracks the state of incomplete TODO items. Having everyt
 - Make an icon if you feel like it
 - Post release to relevant channels
 ** TODO v1.1 tasks
+- emacs lsp implementation
 - finish stretch goals in the [[file:snippets/interactive-devel.rls][interactive development library]]
 - History length configurable (env var?)
 - Lex function
@@ -174,7 +182,6 @@ Note: this section only tracks the state of incomplete TODO items. Having everyt
   - a snippet with a bunch of color constants
 - Search delim configurable
 ** TODO v1.2 release tasks
-- Emacs syntax highlighting and/or LSP implementation
 - Bindings for the simplest possible UI library?
 - Scheme compatibility layer?
 - Get on that bug tracker

Writing.org

@@ -297,7 +297,7 @@ The following table is up to date as of Relish 0.3.0. For latest information try
 |----------------+---------------+----------------+---------+--------+-----------+-----------+-----------+--------+-------------|
 | exit           | set?          | fg             | dq      | div    | concat    | or        | get-paths |        |             |
 |----------------+---------------+----------------+---------+--------+-----------+-----------+-----------+--------+-------------|
-|                |               |                | pop     | gte?   | string    |           | cond      |        |             |
+|                |               | bg             | pop     | gte?   | string    |           | cond      |        |             |
 |----------------+---------------+----------------+---------+--------+-----------+-----------+-----------+--------+-------------|
 |                |               |                | list?   | int    |           |           |           |        |             |
 |----------------+---------------+----------------+---------+--------+-----------+-----------+-----------+--------+-------------|

snippets/relish-mode.el

@@ -0,0 +1,79 @@
+;;; relish-mode.el --- sample major mode for editing Relish. -*- coding: utf-8; lexical-binding: t; -*-
+
+;; Copyright © 2017, by Ava Hahn
+;; Author: Ava Hahn (ava@sunnypup.io)
+;; Version: 1
+;; Keywords: languages
+
+;; This file is not part of GNU Emacs.
+
+;;; License:
+;; You can redistribute this program and/or modify it under the terms of the GNU General Public License version 3.
+
+;;; Code:
+
+(setq relish-keywords
+      (let* (
+             (r-control-flow '("if" "let" "circuit" "while" "assert" "exit"))
+             (r-declaration  '("lambda" "q" "quote" "def" "get-doc" "set-doc" "set?"))
+             (r-shell        '("pipe" "load-to-string" "l" "load" "load-with" "cd" "fg" "bg"))
+             (r-list         '("car" "len" "cons" "cdr" "reverse" "dq" "pop" "list?"))
+             (r-math         '("float" "sub" "mul" "inc" "dec" "div" "gte?" "int" "mod" "exp" "lt?" "gt?" "add" "lte?"))
+             (r-strings      '("strlen" "substr?" "echo" "split" "input" "concat" "string"))
+             (r-bool         '("toggle" "bool" "and" "eq?" "not" "or"))
+             (r-file         '("read-file" "append-file" "write-file" "exists?"))
+             (r-misc         '("call" "help" "env" "eval"))
+             (r-userlib      '("reduce" "prepend" "add-path" "set" "map" "get-paths" "cond"))
+
+             (r-control-flow-regexp (regexp-opt r-control-flow 'words))
+             (r-declaration-regexp (regexp-opt r-declaration 'words))
+             (r-shell-regexp (regexp-opt r-shell 'words))
+             (r-list-regexp (regexp-opt r-list 'words))
+             (r-math-regexp (regexp-opt r-math 'words))
+             (r-strings-regexp (regexp-opt r-strings 'words))
+             (r-bool-regexp (regexp-opt r-bool 'words))
+             (r-file-regexp (regexp-opt r-file 'words))
+             (r-misc-regexp (regexp-opt r-misc 'words))
+             (r-userlib-regexp (regexp-opt r-userlib 'words)))
+
+        `(
+          (,r-control-flow-regexp . 'font-lock-type-face)
+          (,r-declaration-regexp  . 'font-lock-type-face)
+          (,r-misc-regexp         . 'font-lock-type-face)
+
+          (,r-list-regexp         . 'font-lock-builtin-face)
+
+          (,r-math-regexp         . 'font-lock-keyword-face)
+          (,r-strings-regexp      . 'font-lock-keyword-face)
+          (,r-bool-regexp         . 'font-lock-keyword-face)
+
+          (,r-shell-regexp        . 'font-lock-constant-face)
+          (,r-file-regexp         . 'font-lock-constant-face)
+
+          (,r-userlib-regexp      . 'font-lock-function-name-face)
+          )))
+
+(setq relish-mode-syntax-table
+      (let ((table (make-syntax-table)))
+        ;; string delims
+        (modify-syntax-entry ?'  "\"" table)
+        (modify-syntax-entry ?\" "\"" table)
+        (modify-syntax-entry ?`  "\"" table)
+
+        ;; comment delims
+        (modify-syntax-entry ?\; "<" table)
+        (modify-syntax-entry ?\n ">" table)
+
+        table))
+
+(define-derived-mode relish-mode
+  text-mode
+  "Major mode for editing Relish"
+  :syntax-table relish-mode-syntax-table
+  (setq font-lock-defaults '((relish-keywords))))
+
+(add-to-list 'auto-mode-alist '("\\.rls\\'" . relish-mode))
+(add-to-list 'auto-mode-alist '(".relishrc" . relish-mode))
+(provide 'relish-mode)
+
+;;; relish-mode.el ends here