Oil Source Code

Oil is a new Unix shell. It's our upgrade path from bash! (Why Create a New Unix Shell? / 2019 FAQ)

Its source code lives in git.

It's written in Python, but we deploy a native executable by reusing portions of the CPython interpreter.

Contributing

• Make sure to check out the Contributing page.
• Let us know if you have problems getting started by posting on the #oil-dev channel of oilshell.zulipchat.com.
• Feel free to grab an issue from Github. Let us know what you're thinking before you get too far.

Quick Start on Linux

Clone the repo, build the Python extension, and run bin/osh (or bin/oil):

bash$ build/dev.sh minimal
...
# Now you should have a libc.so symlink in the repository root directory

bash$ bin/osh
osh$ name=world
osh$ echo "hello $name"
hello world

Try running a shell script you wrote with bin/osh myscript.sh.

This is called the developer build, and is very different from the release tarball. The Contributing page describes this difference in detail.

The release tarballs are linked from the home page. (Developer builds don't work on OS X, so use the release tarballs on OS X.)

Run bin/oil to try the Oil language. Send me feedback about it!

Docs

The Wiki has many developer docs. Feel free to edit them. If you make a major change, let us know on Zulip!

There are also READMEs in some subdirs, like opy/ and mycpp/.

If you're confused, the best thing to do is to ask on Zulip and someone should produce a pointer and/or improve the docs.

Docs for end users are linked from each release page.

Repository Structure

Try this to show a summary of what's in the repo and their line counts:

$ metrics/source-code.sh all

(Other functions in this file may be useful as well.)

A Collection of Interpreters

Oil is naturally structured as a set of mutually recursive parsers and evaluators.

bin/              # Main entry points (bin/osh)
osh/              # OSH parser and evaluator
oil_lang/         # Oil parser and evaluator
frontend/         # Lexing/Parsing code common to Oil and OSH
core/             # Other code shared between Oil and OSH
pylib/            # Borrowed from the Python standard library.
native/           # Python extension modules, e.g. libc.c
cpp/              # C++ code which complements the mycpp translation
tools/            # User-facing tools, e.g. the osh2oil translator
Python-2.7.13/    # CPython is the initial basis for the Oil VM

DSLs / Code Generators

Oil is implemented with DSLs and metaprogramming, for "leverage".

asdl/             # ASDL implementation, derived from CPython
pgen2/            # Parser Generator, borrowed from CPython
mycpp/            # Experimental translator from typed Python to C++.
                  # Depends on MyPy.
opy/              # Python compiler in Python
  lib/            # Common code
  compiler2/      # Bytecode compiler
  byterun/        # Metacircular bytecode VM in Python
  gold/           # tests
  byterun/        # Unused bytecode interpreter

Tests

Unit tests are named foo_test.py and live next to foo.py.

test/             # Test automation
  unit.sh         ## Types of test runner: unit, spec, wild, smoke
  spec.sh
  wild.sh
  smoke.sh
  sh_spec.py      # shell spec test framework
testdata/
gold/             # Gold Test cases
spec/             # Spec test cases
  bin/            # tools used in many spec tests
  testdata/       # scripts for specific test cases
  errors/         # TODO: migrate these bad shell scripts
types/            # Scripts for running MyPy and PyAnnotate, etc.

Dev Tools and Scripts

We use a lot of automation to improve the dev process. It's largely written in shell, of course!

benchmarks/       # Benchmarks should be run on multiple machines.
metrics/          # Metrics don't change between machines (e.g. code size)
build/            # Build automation
  oil-defs/       # Files that define our slice of CPython.
  dev.sh          # For development builds, running CPython
devtools/         # For Oil developers (not end users)
  release.sh      # The (large) release process.
demo/             # Demonstrations of bash/shell features.  Could be
                  # moved to tests/ if automated.
misc/             # A junk drawer
web/              # HTML/JS/CSS for tests and tools

Temp Dirs

Directories that begin with _ are not stored in git. The dev tools above create and use these dirs.

_bin/             # Native executables are put here
_build/           # Temporary build files
_devbuild/        # Developer build files not deleted upon 'make clean'
  gen/            # Generated Python and C code
_deps/            # build dependencies like re2c
_tmp/             # Test suites and other temp files
  spec/
  wild/
    raw/
    www/
  osh-parser/
  osh-runtime/
  vm-baseline/
  oheap/
  startup/
  ...
_release/         # Source release tarballs are put here
  VERSION/        # Published at oilshell.org/release/$VERSION/
    benchmarks/
    doc/
    metrics/
    test/
      spec.wwz
      wild.wwz
      ...
    web/          # Static files, copy of $REPO_ROOT/web
      table/

End user build system

This is very different than the developer build of Oil.

Makefile
configure
install

Docs

doc/              # A mix of docs
README.md         # For Oil developers

LICENSE.txt       # For end users
INSTALL.txt

More info

• The blog has updates on the project status.
• Oil Home Page
• oilshell.zulipchat.com is for any kind of discussion
• Subscribe for updates:
  • /r/oilshell on Reddit
  • @oilshellblog on Twitter