ICR - Interactive Crystal

Interactive console for Crystal Programming Language.

• Usage
  • Require local files
• Installation
  • Arch Linux
• How does it work?
• Commands and special locals
• Update check
• Development
• Editor Integration
• Contributors

Usage

It's like irb, but for Crystal:

Require local files

You can require local files by relative path (starts with ./):

require "./src/my_cool_lib"

Libs can also be required from the cli:

$ icr -r colorize -r ./src/my_cool_lib

Installation

Prerequisites:

• The latest version of crystal.
• Readline (for Debian/Ubuntu install libreadline6-dev package).
• LLVM development files.

Clone the repo:

git clone https://github.com/crystal-community/icr.git

Switch to repo-directory:

cd icr

Build:

make

Install:

sudo make install

As a shard dependency

If you would like to include icr as a dependency, you can add it to your shard.yml

dependencies:
  icr:
    github: crystal-community/icr
    branch: master

Then just run shards install from your project!

Enjoy!

Arch Linux

Arch Linux users can install ICR from AUR.

How does it work?

• Every time you press Enter it adds a new instruction, generates a new crystal program, and executes it.
• The output is split into 2 parts: regular program output (e.g. output from puts 10) and the value returned by the last command.
• The regular output is saved, and when you type a new instruction, a new program is generated. The saved output is subtracted from the new output, and the difference is printed out. It creates an illusion that only new instructions are executed :)

Commands and special locals

• paste - enables paste mode
• debug - toggles debug mode off and on. In debug mode icr will print the code before executing it
• quit or exit - exits current interactive console
• reset - clears out all of the accumulated commands
• __ - holds the result of the last expression. Example:

icr > "5" + "2"
=> "52"
icr > __.to_i - 10
=> 42

Update check

ICR periodically checks for the new releases on Github. If your current version is out of date, it will simply show you a notice at start.

You can disable this behavior using --disable-update-check CLI flag.

Development

To run tests:

make test

Editor integration

• inf-crystal.el - Connects REPL buffer to the ICR subprocess in Emacs

Contributors

• greyblake Potapov Sergey - creator, maintainer
• BlaXpirit Oleh Prypin - fixes for Crystal 0.16
• puppetpies Brian Hood - support of records
• jwoertink Jeremy Woertink - support of -r option and number of other contributions
• veelenga V. Elenhaupt - maintenance
• MakeNowJust TSUYUSATO Kitsune - syntax highlight support