https://github.com/comby-tools/comby
A code rewrite tool for structural search and replace that supports ~every language.
https://github.com/comby-tools/comby
c go java javascript linting parser-combinators parsing php program-transformation python reason refactoring regex rewriting rust search-and-replace swift syntax syntax-transformation typescript
Last synced: about 12 hours ago
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A code rewrite tool for structural search and replace that supports ~every language.
- Host: GitHub
- URL: https://github.com/comby-tools/comby
- Owner: comby-tools
- License: apache-2.0
- Created: 2019-04-08T21:35:40.000Z (about 6 years ago)
- Default Branch: master
- Last Pushed: 2025-03-20T06:34:26.000Z (25 days ago)
- Last Synced: 2025-04-07T01:00:58.158Z (8 days ago)
- Topics: c, go, java, javascript, linting, parser-combinators, parsing, php, program-transformation, python, reason, refactoring, regex, rewriting, rust, search-and-replace, swift, syntax, syntax-transformation, typescript
- Language: OCaml
- Homepage: https://comby.dev
- Size: 1.82 MB
- Stars: 2,470
- Watchers: 23
- Forks: 64
- Open Issues: 79
-
Metadata Files:
- Readme: README.md
- Contributing: docs/CONTRIBUTING.md
- License: LICENSE
- Code of conduct: docs/CODE_OF_CONDUCT.md
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README
# comby
[](LICENSE)
[](https://codecov.io/gh/comby-tools/comby)
[](Downloads)
[](Commit)
### See the [usage documentation](https://comby.dev).
[A short example below](https://github.com/comby-tools/comby#isnt-a-regex-approach-like-sed-good-enough) shows how comby simplifies matching and rewriting compared to regex approaches like `sed`.
Comby supports interactive review mode (click here to see it in action).
## Install (pre-built binaries)
### Mac OS X
- `brew install comby`
### Ubuntu Linux
- `bash <(curl -sL get-comby.netlify.app)`
- **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](https://github.com/comby-tools/comby#build-from-source).
### Windows
- [Install the Windows Subsystem for Linux](https://docs.microsoft.com/en-us/windows/wsl/install-win10) and install Ubuntu. Then run `bash <(curl -sL get.comby.dev)`
### Docker
- `docker pull comby/comby`
click to expand an example invocation for the docker image
Running with docker on `stdin`:
```bash
docker run -a stdin -a stdout -a stderr -i comby/comby '(:[emoji] hi)' 'bye :[emoji]' lisp -stdin <<< '(👋 hi)'
```
### Or [try it live](https://bit.ly/2UXkonD).
## 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](https://twitter.com/rvtond) on Twitter.
```c
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](https://bit.ly/30935ou).
## Build from source
- Install [opam](https://opam.ocaml.org/doc/Install.html). 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 libev4 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 . --deps-only
```
- Build and test
```
make
make test
```
- Install `comby` on your `PATH` by running
```
make install
```