Simple Lisp Shell (pronounced slosh)

Note this is a new expermental version, see ./legacy/ for the original version (slush).

Simple Lisp SHell (sl-sh) is a lisp based shell written in Rust. It is not POSIX compliant and makes no effort to be. Sl-sh should run on any *nix platform as well as macOS (CI currently only tests against ubuntu and macOS).It is a Lisp-1 that is heavily inspired by Clojure and Common Lisp. It is a shell, it is a scripting language, and it is a REPL.

Some of the more prominent features:

• The contains both a shell and a lisp reader so familiar bash-isms like

  cat file | tr -s " " | cut -d " " -f 2,4
  "just work"
• Support for an rc file, ~/.config/slosh/init.slosh, to set up environment and fully customize your prompt.
• Common Lisp style macro system with support for quote and backquote (with clojure style ~ and ~@ expansion).
• Dynamically Typed
• Note lacks many features from legacy sl-sh but catching up (std lib is currently tiny).

Contains these crates:

• slosh: a REPL with debugger and extensions that use compiler, includes shell functionality.
• compiler: the core compiler code
• compile_state: helper crate with state contained by a VM for use with compiler
• vm: this is the bytecode VM that is target of the compiler
• builtins: set of some core builtins
• shell: contains shell specific code, this includes a shell reader (parser), job control etc
• bridge_macros: macros for exported Rust functions as slosh functions
• bridge_types: helper types for code using bridge_macros
• legacy (excluded): original sl-sh version, more complete but slower and worse core shell support

Running

cargo run -p slosh

Installation

1. Get sl-sh

• Install git

  git clone https://github.com/sl-sh-dev/sl-sh
  cd slsh
  

2. Build sl-sh

• Install Rust and build from source:

  
  cargo build -p slosh --release
  ./target/release/slosh
  

3. Use sl-sh as primary shell

• install binary

sudo install -D -m 755 target/release/slosh /usr/local/bin/

• add slosh to /etc/shells and change login shell to slosh

echo /usr/local/bin/slosh | sudo tee -a /etc/shells
chsh -s /usr/local/bin/slosh

Compiler

These are a subset of sl-sh forms and most work exactly the same. See the sl-sh docs at: https://sl-sh-dev.github.io/sl-sh/mydoc_api.html

Primitive types

• True
• False
• Nil
• String Constant
• Symbol
• Keyword
• Character (chars are grapheme clusters)
• Float (32 bits- f32)
• Integer (56 bit signed integer)
• Byte

Heap allocated objects (complex types)

• Pair/ConsCell
• Vector
• HashMap
• String

Special Forms

The following special forms are currently in the compiler:

• def
• set!
• do
• fn
• macro
• if
• quote (')
• back-quote (` supports ~ ~@)
• and
• or
• err
• let
• call/cc
• defer
• on-error
• while

Compiled Forms

Normal forms follow normal calling evaluation. Note: These are all compiled to bytecode and once compiled are not dynamic anymore.

• not
• recur
• this-fn
• type
• +
• -
• *
• /
• inc!
• dec!
• list
• list-append
• cons
• car
• cdr
• xar!
• xdr!
• vec
• make-vec
• vec-push!
• vec-pop!
• str
• =
• /=
• <
• <=
• >
• >=
• eq?
• equal?

Features

• Lisp reader (no reader macros yet)
• Lisp lists (pair/concell based)
• Vectors
• Tail call optimization
• Continuations (call/cc)
• Lambda/Closures (supports optional and variadic arguments)
• Garbage collection (basic but should function)
• Lisp back quotes (including nested back quotes)
• Macros

slosh

Slosh is the shell and scripting language REPL using the compiler, vm and shell crates.

Built-in Forms

These forms (written in Rust but callable from Lisp) are supported.

• pr (print)
• prn (println)
• dasm (disassemble a lambda or closure)
• load (load a lisp file and execute it)
• vec-slice (new vec that is a slice of old vec)
• vec->list (turn a vec to a list)
• get-prop (get a property from an object- either a global variable or a heap object)
• set-prop (set a property on an object- either a global variable or a heap object)
• eval (eval an expression)

Features

• Line editor with history
• Debug on error, currently useful for probing VM state only

Links

• sl-sh legacy shell: https://github.com/sl-sh-dev/sl-sh/legacy