comby

A tool for structural code search and replace that supports ~every language
README







See the usage documentation.

A short example below shows how comby simplifies matching and rewriting compared to regex approaches like sed.

Need help writing patterns or have other problems? Post them in Gitter.

Install (pre-built binaries)

Mac OS X

  • brew install comby

Ubuntu Linux

  • bash <(curl -sL get.comby.dev)

  • Other Linux distributions: The PCRE library is dynamically linked in the Ubuntu binary. For other distributions like Arch Linux, a fixup is needed: sudo ln -s /usr/lib/libpcre.so /usr/lib/libpcre.so.3. On Fedora, use sudo ln -s /usr/lib64/libpcre.so /usr/lib64/libpcre.so.3. Alternatively, consider building from source.

Windows

Docker

  • docker pull comby/comby

Running with docker on stdin:

docker run -a stdin -a stdout -a stderr -i comby/comby '(:[emoji] hi)' 'bye :[emoji]' lisp -stdin <<< '(👋 hi)'

Or try it live.

Isn't a regex approach like sed good enough?

Sometimes, yes. But often, small changes and refactorings are complicated by nested expressions, comments, or strings. Consider the following C-like snippet. Say the challenge is to rewrite the two if conditions to the value 1. Can you write a regular expression that matches the contents of the two if condition expressions, and only those two? Feel free to share your pattern with @rvtond on Twitter.

if (fgets(line, 128, file_pointer) == Null) // 1) if (...) returns 0
      return 0;
...
if (scanf("%d) %d", &x, &y) == 2) // 2) if (scanf("%d) %d", &x, &y) == 2) returns 0
      return 0;

To match these with comby, all you need to write is if (:[condition]), and specify one flag that this language is C-like. The replacement is if (1). See the live example.

Build from source

  • Install opam. TL;DR do sh <(curl -sL https://raw.githubusercontent.com/ocaml/opam/master/shell/install.sh)

  • Run this if you don't have OCaml installed (it bootstraps the OCaml compiler):

opam init
opam switch create 4.11.0 4.11.0
  • Run eval $(opam env)

  • Install OS dependencies:

    • Linux: sudo apt-get install autoconf libpcre3-dev pkg-config zlib1g-dev m4 libgmp-dev libev-dev libsqlite3-dev

    • Mac: brew install pkg-config gmp pcre libev

  • Then install the library dependencies:

git clone https://github.com/comby-tools/comby
cd comby 
opam install ./comby-kernel.opam --deps-only
opam install ./comby-semantic.opam --deps-only
opam install ./comby.opam --deps-only
  • Build and test

make
make test
  • Install comby on your PATH by running

make install
Install
Published
17 Jun 2021
Sources
comby-kernel.1.7.0.tar.gz
md5=ee6556d8bd9b25ed0445ebe23862e48a
sha512=e6386c8ce5ef14bbcab2b0ead5b1edc39375438f56330d5f02e81e467afe6623a7e299f97f26008d77bbc62850c6dc63a7cbe5b81671b5183ff3adeee5946bb3
Dependencies
Reverse Dependencies