elvish/README.md

A novel Unix shell

This project aims to explore the potentials of the Unix shell. It is a work in progress; things will change without warning.

The wiki has a random list of things you might want to know. The issues list contains many things I'm working on.

The Interface

Syntax highlighting (also showcasing right-hand-side prompt):

Tab completion for files:

Navigation mode (triggered with ^N, inspired by ranger):

Planned features:

• Auto-suggestion (like fish)
• Programmable line editor
• Directory jumping (#27)
• A vi keybinding that makes sense
• History listing (like ptpython)
• Intuitive multiline editing

The Language

Some things that the language is already capable of:

• External programs and pipelines: (~> is the prompt):

  ~> vim README.md
  ...
  ~> cat -v /dev/random
  ...
  ~> dmesg | grep -i acpi
  ...
  

• Arithmetics using the prefix notation:

  ~> + 1 2
  ▶ 3
  ~> mul (+ 1 2) 3
  ▶ 9
  

• Quoting:

  ~> echo "|  C'est pas une pipe."
  |  C'est pas une pipe.
  

• Lists and maps:

  ~> println list: [a list] map: [&key value]
  list: [a list] map: [&key value]
  ~> println [a b c][0]
  a
  ~> println [&key value][key]
  value
  

• Variables:

  ~> v=[&foo bar]; put $v[foo]
  ▶ bar
  

• Defining functions:

  ~> fn map [f xs]{ put [(put $@xs | each $f)] }
  

• Lisp-like functional programming:

  ~> map [x]{+ 10 $x} [1 2 3]
  [11 12 13]
  ~> map [x]{div $x 2} (map [x]{+ 10 $x} [1 2 3])
  [5.5 6 6.5]
  

• More natural concatenative style:

  ~> put 1 2 3 | each [x]{+ 10 $x} | each [x]{div $x 2}
  ▶ 5.5
  ▶ 6
  ▶ 6.5
  

• A separate env: namespace for environmental variables:

  ~> put $env:HOME
  ▶ /home/xiaq
  ~> env:PATH=$env:PATH":/bin"
  

Getting elvish

Prebuilt binaries

Prebuilt binaries are available for 64-bit Linux and Mac OS X. They are always built using the latest commit that builds.

Building It Yourself

Go >= 1.5 is required. This repository is a go-getable package.

Linux is fully supported. It is likely to work on BSDs and Mac OS X. Windows is not supported yet.

In case you are new to Go, you are advised to read How To Write Go Code, but here is a quick snippet:

export GOPATH=$HOME/go
export PATH=$PATH:$GOPATH/bin
go get github.com/elves/elvish
elvish

To update and rebuild:

go get -u github.com/elves/elvish

Remember to put the two exports above into your bashrc or zshrc (or whatever).

Name

In roguelikes, items made by the elves have a reputation of high quality. These are usually called elven items, but I chose elvish for an obvious reason.

The adjective for elvish is also "elvish", not "elvishy" and definitely not "elvishish".

Test coverages:

Package	Coverage
edit
eval
glob
parse
store
sys
util