Lambda Calculus Repl

An intuitive repl for lambda calculus written in Elm.

Try repl here!

Features

• Cell-based repl with easy navigation
• Seamless multi-line cell editing
• Instant evaluations and problem feedbacks
• Auto save repl
• Support several color themes
• Tailored experiences for all devices

Themes

Light

Solarized Light

Dark

Development

1. Install elm-live.

2. At the project root directory, start elm-live server

./start.sh

Note: You may need to run chmod +x ./start.sh to enable execution permission.

Deployment

At the project root directory, run build.sh to create an optimized and minimized build:

./build.sh

Note: You may need to run chmod +x ./build.sh to enable execution permission.

License

MIT

Change Log

Release 0.7.0

• Align repl to top of window
• Fix icon z-index hierarchy
• Color error messages tomato red

Release 0.6.0

• Support expr without name in repl
• Fix indentation parsing
• Properly handle key up and down in multi-row cells
• Allow comments before and after def or expr in repl
• Support 3 color themes

Release v0.5.0

• Add close active cell button
• Better visual hierarchy in popups
• Add link to source code in help popup

Release v0.4.0

• Fix substitution issues by switching to De Bruijn Indices
• Support full evaluation
• Protect against infinite recursion like the merge function (\x. x x) (\x. x x)
• Clean up parentheses wrapping
• Return evaluated defs in original order

Release v0.3.0

• Save model automatically to LocalStorage
• Add settings popup for evaluation strategy
• Add tooltips for buttons

Release v0.2.0

• Evaluate all cells when editing one cell
• Track cell index in checker for problems like duplicated definition
• Enforce end of def and expr when parseDef and parseExpr
• Replace line prompt with cell index
• Place add cell button at the active cell

Release v0.1.0

• Basic repl support