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Prybar is a universal interpreter front-end. Same interface, same REPL, different languages.


At, we're in the business of running REPLs. As it happens to be, every language implements them differently. We wanted them to all behave the same: run code and drop into a REPL!

How it works

Prybar, written in Go, maintains a common command-line interface that calls into a select language backend. When possible, the language backends are implemented using cgo and the language's C-bindings. Otherwise, they make use of a small script written in the host language which starts a Prybar-compatible REPL.


Usage: ./prybar-LANG [FLAGS] [FILENAME]...
  -I	interactive (use readline repl)
  -c string
    	execute without printing result
  -e string
    	evaluate and print result
  -i	interactive (use language repl)
  -ps1 string
    	repl prompt (default "--> ")
  -ps2 string
    	repl continuation prompt (default "... ")
  -q	don't print language version

Language Support

language eval eval expression eval file repl repl like eval set prompt
Clojure -
Emacs Lisp
Javascript (nodejs)
Javascript (spidermonkey) -
Lua 5.1
Python 2.7
Python 3.x
Ruby 2.5
Tcl -

Build and run

% make help
  make all          Build all Prybar binaries
  make prybar-LANG  Build the Prybar binary for LANG
  make docker       Run a shell with Prybar inside Docker
  make image        Build a Docker image with Prybar for distribution
  make test         Run integration tests
  make test-image   Test Docker image for distribution
  make clean        Remove build artifacts
  make help         Show this message

Prybar uses Docker to make it easy to get started with development. First, you must install Docker. Then, run:

$ make docker

to create a Docker image containing the Prybar code and all of its dependencies, and launch a shell inside of it. The Prybar source repository will be synchronized with the working directory of the container's filesystem, so you only need to re-run make docker if you change the Dockerfile or any of its scripts.

To build Prybar (this should be done inside make docker unless you have installed all of Prybar's dependencies on your system), run make or make all. Then the prybar-LANG binaries will be available in the working directory and on $PATH, one for each supported language LANG (see the languages subdirectory of this repository):

$ prybar-python3 -h


Run make image to create a Docker image containing not only Prybar's dependencies and source code but also its compiled binaries, which can be embedded inside other Docker images by means of COPY --from=basicer/prybar.

This image is automatically built and deployed to Docker Hub every time a commit is merged to master.


Copyright (C) 2004-2018 Neoreason, Inc. et al.

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA.

See the COPYING file for more information regarding the GNU General Public License.