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Editor Setup for Cure String Literals

This guide helps you configure your editor to easily input Unicode curly quotes (' and ') for Cure charlist literals.

Implementation Status: Charlist literals with Unicode curly quotes are fully implemented in the Cure lexer and tested (see test/string_lexer_test.erl). However, in practice, most Cure code uses regular strings ("hello") for text. Charlists are primarily for Erlang interoperability when needed.

Quick Reference

Cure uses different quote characters for different purposes:

Character	Unicode	Usage	Example
`"`	U+0022	String literals	`"hello"`
`'`	U+2018	Charlist start	`'hello'`
`'`	U+2019	Charlist end	`'hello'`
`:`	U+003A	Atoms (recommended)	`:my_atom`
`'`	U+0027	Atoms (alternative)	`'my_atom'`

Operating System Methods

macOS

System-wide Keyboard Shortcuts:
- Left curly quote ': Option + ]
- Right curly quote ': Option + Shift + ]

Text Substitution (Automatic):
1. Open System Preferences → Keyboard → Text
2. Add entries:
- Replace: '' → With: '' (two single curly quotes)
- Or configure your preferred trigger

Linux

Compose Key Method:
1. Set a compose key in your keyboard settings
2. Use sequences:
- ' (left): Compose < '
- ' (right): Compose > '

XKB Custom Layout:
Create a custom keyboard layout in ~/.config/xkb/symbols/custom:

partial alphanumeric_keys
xkb_symbols "cure_quotes" {
    include "us(basic)"
    key <AC10> { [ apostrophe, quotedbl, U2018, U2019 ] };
};

Apply with: setxkbmap -option "custom:cure_quotes"

Windows

AutoHotkey Script:

Save as cure_quotes.ahk:

; Cure Charlist Quotes
; Press Alt+[ for left curly quote
; Press Alt+] for right curly quote

![ ::SendInput {U+2018}  ; Alt+[
!] ::SendInput {U+2019}  ; Alt+]

Run the script on startup.

Editor-Specific Configurations

VS Code

Method 1: Custom Keybindings

Add to keybindings.json:

[
  {
    "key": "alt+[",
    "command": "type",
    "args": { "text": "'" },
    "when": "editorTextFocus && editorLangId == 'cure'"
  },
  {
    "key": "alt+]",
    "command": "type",
    "args": { "text": "'" },
    "when": "editorTextFocus && editorLangId == 'cure'"
  }
]

Method 2: Snippets

Add to Cure language snippets:

{
  "Charlist Literal": {
    "prefix": "cl",
    "body": "'$1'",
    "description": "Insert charlist literal with curly quotes"
  }
}

Method 3: Text Expander Extension

Install an extension like "Text Expander" and configure:
- 'c → ' (left curly quote)
- c' → ' (right curly quote)

Vim/Neovim

Method 1: Insert Mode Mappings

Add to .vimrc or init.vim:

" Cure charlist quotes
inoremap <A-[> '
inoremap <A-]> '

" Or use digraphs (Ctrl+K followed by code)
" '<' for U+2018, '>' for U+2019

Method 2: Abbreviations

" Auto-expand ''c to charlist quotes
autocmd FileType cure inoreabbrev ''c ''

Method 3: Custom Digraphs

digraphs c< 8216  " '<
digraphs c> 8217  " '>

Then use: Ctrl+K c < for '

Emacs

Method 1: Custom Keybindings

Add to .emacs or init.el:

;; Cure charlist quotes
(define-key cure-mode-map (kbd "M-[") 
  (lambda () (interactive) (insert "'")))
(define-key cure-mode-map (kbd "M-]") 
  (lambda () (interactive) (insert "'")))

Method 2: Abbrev Mode

(define-abbrev cure-mode-abbrev-table "'c" "''")

Method 3: YASnippet

Create cure-mode/charlist.yasnippet:

# -*- mode: snippet -*-
# name: charlist
# key: cl
# --
'$1'$0

Sublime Text

Method 1: Key Bindings

Add to Preferences → Key Bindings:

[
  {
    "keys": ["alt+["],
    "command": "insert_snippet",
    "args": {"contents": "'"}
  },
  {
    "keys": ["alt+]"],
    "command": "insert_snippet",
    "args": {"contents": "'"}
  }
]

Method 2: Snippets

Create cure-charlist.sublime-snippet:

<snippet>
    <content><![CDATA['$1']]></content>
    <tabTrigger>cl</tabTrigger>
    <scope>source.cure</scope>
    <description>Charlist Literal</description>
</snippet>

IntelliJ IDEA / WebStorm

Live Templates:

Go to Settings → Editor → Live Templates
Create new template group "Cure"
Add template:
- Abbreviation: cl
- Template text: '$END$'
- Applicable in: Cure files

Keymap:

Settings → Keymap
Search for "Insert Live Template"
Add shortcut: Alt+[ for ', Alt+] for '

Atom

Snippets:

Add to snippets.cson:

'.source.cure':
  'Charlist Literal':
    'prefix': 'cl'
    'body': "'$1'"

Keybindings:

Add to keymap.cson:

'atom-text-editor[data-grammar="source cure"]':
  'alt-[': 'snippets:insert-text-left-curly-quote'
  'alt-]': 'snippets:insert-text-right-curly-quote'

Language Server / LSP Support

If you're using a Cure language server, it can provide:

Auto-Closing Pairs:
- Typing ' automatically inserts '
- Cursor positioned between quotes

Snippet Completion:
- Type char or cl → charlist literal template

Diagnostics:
- Warns when using ASCII ' for charlists
- Suggests correction to Unicode quotes

Copy-Paste Method

If configuring your editor is too complex, you can:

Create a file snippets.txt with commonly-used patterns:
'' (empty charlist) 'hello' 'world'
Copy-paste as needed
Or use a clipboard manager with pre-configured snippets

Testing Your Setup

Create a test file test.cure:

module Test do
  export [main/0]

  import Std.Io [println/1]

  def main(): Int =
    # String literal (straight quotes)
    let str = "hello"
    println(str)

    # Charlist literal (curly quotes) - stores as [104, 101, 108, 108, 111]
    # let chars = 'hello'

    # Atom (ASCII single quote)
    let atom = :my_atom

    0
end

Verify:
- "hello" → String (UTF-8 binary)
- 'hello' → Charlist (list of Unicode codepoints: [104, 101, 108, 108, 111])
- :my_atom → Atom (recommended syntax)
- 'my_atom' → Atom (alternative ASCII single quote syntax)

Troubleshooting

Characters Not Displaying

Issue: Curly quotes show as boxes or question marks

Solution: Ensure your editor uses a Unicode-aware font:
- Recommended fonts: Fira Code, JetBrains Mono, Source Code Pro
- Enable UTF-8 encoding in editor settings

Incorrect Character Inserted

Issue: Wrong Unicode character inserted

Solution:
- Verify the Unicode codepoints: U+2018 (left) and U+2019 (right)
- Check your keyboard layout or input method
- Use xxd or a Unicode inspector to verify characters

Auto-Pairing Conflicts

Issue: Editor's auto-pairing interferes with charlist quotes

Solution:
- Disable auto-pairing for single quotes in Cure files
- Configure language-specific settings
- Use explicit keybindings instead of relying on editor defaults

Alternative: ASCII Syntax (Not Recommended)

If Unicode input is impossible in your environment, you can use ASCII single quotes for atoms instead:

# ASCII single quote for atoms (fully supported)
atom = 'my_atom'

# Or use colon prefix (recommended)
atom = :my_atom

Note: Charlists with Unicode curly quotes are implemented and tested in the compiler (see test/string_lexer_test.erl), but are rarely used in practice. Most Cure code uses strings ("hello") for text and atoms (:atom) for symbolic values.

Contributing

Found a better method for your editor? Please contribute:

Fork the Cure repository
Update this document with your configuration
Submit a pull request

See CONTRIBUTING.md for guidelines.

Resources

Unicode Character Table
Curly Quotes vs Straight Quotes
Cure Syntax Guide
String Lexer Tests - Reference implementation tests

Support

Need help configuring your editor?

Open an issue on GitHub
Join the Cure community chat
Check the FAQ in the main documentation

Happy coding! 🎉