The OCaml Style Checker

A style checker for OCaml language.

Overview

The OCaml Style Checker is a tool for OCaml sources. Its allows to automatically check the conformance of your code to some coding rules. ocp-lint is highly configurable and easily extensible.

Dependencies

ocp-lint is currently written for OCaml 4.02 and superior versions.

OPAM dependencies: ocp-build, menhir, yojson, ppx_tools

You can use make opam-deps to install dependencies in the current switch.

Build Instructions

Use the following instructions:

$ make opam-deps (if you are using OPAM)
$ ./configure
$ make
$ make install

to compile and install ocp-lint on your system.

Running

Easiest Way

You can just run ocp-lint in the home directory of your project, and the tool will recursively scan sub-directories, analyze your source files and report warning and/or errors. If you are using emacs, it's better to run the command inside the editor to be able to quickly jump to locations of reported errors and/or warnings.

Initialization, Global Configuration and Database

As explained above, ocp-lint is ready to work by just running one command, and without arguments. No pre-configurations or additional information are required to start using it. However, it may be better to run ocp-lint --init once to:

• create a database (directory _olint) to store ocp-lint results and avoid useless computations when files are not modified,

• create a global configuration file (called .ocp-lint) that you can customize for your needs.

Pre-commit Hooks

If you are using Git, it is highly preferable to add a pre-commit hook to prevent you from commiting source files for which ocp-lint reports some warning and/or errors. To do that, create a file .git/hooks/pre-commit (with execution premissions) with the following content:

#!/bin/sh

LINT=ocp-lint # or the exact path to ocp-lint

$LINT --warn-error --path <absolute/path/to/your/project_source>

if [ "$?" = 0 ]; then
    exit 0
else
    echo "\n/!\\ ocp-lint: please fix the warnings before commiting./!\\"
    exit 1
fi

Options

ocp-lint comes will a large set of options. With those options, you can tweek the behavior of ocp-lint or configure the plugins that offers options. In order to use those options, you either use the command-line or the configuration file. One thing to note is that the command-line have the priority over the configuration file.

Command-line options

Kernel arguments

ocp-lint offers a lot of options to change the way it runs. Here some examples:

• --path DIR: Give a project dir path

• --list: List of every plugins and linters

Plugin arguments

Each plugin comes with a set of options:

• --plugin-name.linter-name.warnings: Enable/Disable warnings from "Checks on module type name."

• --{enable,disable}-plugin-name.linter-name: Enable/Disable linter "Checks on module type name."

To those options the author of the plugins can add his own options. Eg:

• --plugin-text.code-length.max-line-length: allows to choose the maximum line length (default value: 80)

• --plugin-parsetree.code-identifier-length.min-identifier-length: allows to choose the minimum identifier length (default value:2)

Configuration file

General use

ocp-lint allows you to manage the options in a configuration file. This file is .ocplint. You can generate it with the --save-config argument.

This file has the following format :

option_name = value
plugin1_name = {
  linter1_name = {
    option1_name = value
    option2_name = value
  }
  linter2_name = { .. }
}
plugin2_name = { .. }

ocp-lint will look for a .ocplint where you run it.

Multi config files

You can use several configuration files in your source in order to manage the options more accurely. If you use an .ocplint in the subdir, the configuration will be use only for the sources in this dir. If you use 2 .ocplint files, one at the root of your project and one in a deep subdir, then ocp-lint will use the root .ocplint for all sources except for the source in the subdir. The sources in the subdir will options that result after merging the 2 .ocplint.

Available Analyses

You can check the generated documentation here.

Contributing

Bug Reports

If you have some bugs, you can submit a bug report or you can fork this repository and make a pull request with a bug fix.

All contributions are welcome !

Licensing, Support and Dev on Demand

The OCaml Style Checker is a free-software. It is distributed under the terms of GNU Public Licence version 3.0. However, to keep to project alive, don't hesitate to support our development and/or maintenance. We can also develop additional plugins for your particular needs.