readline

Crystal bindings to GNU Readline Library.

Installation

  1. Add the dependency to your shard.yml:

    dependencies:
  readline:
    github: crystal-lang/crystal-readline

  2. Run shards install

Usage

require "readline"

user_input = Readline.readline("> ")

Troubleshooting

Static linking

If you build your binary with crystal build --static you might encounter errors like these:

(.text+0x678): undefined reference to `PC'
(.text+0x687): undefined reference to `BC'
(.text+0x68e): undefined reference to `UP'
(.text+0x728): undefined reference to `tgetent'
(.text+0x76f): undefined reference to `tgetstr'
(.text+0x799): undefined reference to `PC'
(.text+0x7af): undefined reference to `BC'
(.text+0x7bd): undefined reference to `UP'
(.text+0x7cf): undefined reference to `tgetflag'
(.text+0x81e): undefined reference to `tgetflag'
(.text+0x938): undefined reference to `tgetflag'

In this case you may need to explicitly link to libtermcap. Crystal offers the --link-flags option but it doesn't let you specify where to insert the new flags, and this is order dependent. Luckily, the linker doesn't complain about duplicate flags, so you can link libtermcap like so:

$ crystal build --static --link-flags "-rdynamic -static -lreadline -ltermcap" main.cr

Contributing

  1. Fork it (https://github.com/crystal-lang/crystal-readline/fork)
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Add some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create a new Pull Request