README - gaplint - by James D. Mitchell and Simon Tollman

gaplint automatically checks the format of a GAP file according to some conventions, which are somewhat configurable. It prints the nature and location of instances of any instances of violations of these conventions (see below for more details).

Installation

Simply run::

$ pip install gaplint

Usage

To use it::

$ gaplint --help

List of all rules

To disable all rules for a particular file you can add the line::

# gaplint: disable = all

to the start of the file before any lines that contain any code. All rules are enabled by default.

.. image:: all-rules.png :width: 750 :alt: A list of all gaplint rules.

You can obtain an explanation of a rule at the command line using the --explain flag, i.e. --explain W000,W001.

Configuration

Certain parameters can be configured, for example, the maximum number of characters permitted per line. All rules are enabled by default but can be disable at the command line, by comments in the file itself, or in a configuration file .gaplint.yml.

Configuration keywords:

• columns: maximum number of characters per line. Defaults to 80.
• disable: rules can be disabled using their name or code. Defaults to no rules disabled.
• dupl-func-min-len: only warn about duplicate functions with at least this many lines. Defaults to 4.
• enable: rules can be enabled using their name or code. Defaults to all rules enabled.
• indentation: minimum indentation of nested statements. Defaults to 2.
• max-warnings: maximum number of warnings before gaplint aborts. Defaults to 1000.

A list of all of the rules that gaplint can apply is given below.

You can alter the configuration in various places, the order of precedence of these is governed by the hierarchy described below. A preference given somewhere higher in the hierarchy will be given precedence.

Configuration

Via the command line ^^^^^^^^^^^^^^^^^^^^

These preferences will be applied for a single run of gaplint only (though multiple files may be linted in this run). To configure gaplint to be run on file1, file2, ..., with preferences as in the example above, we enter the following into the command line::

   gaplint --columns=100 --indentation=4 --disable=W002,W028 file1 file2 ...

Via comments in source files ^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Any rule, including all, can be suppressed for a specific line or for a whole file:

• To supress a rule(s) for a given line, include the following after the line of code for which the rule is to be suppressed::

  gaplint: disable=, ...

• If the above is too long to fit after the relevant line of code, suppressions can be declared in the line above for the line below by including (nextline)::

  gaplint: disable(nextline)=, , ...

• If rules have been suppressed for a given line using both the in-line and nextline options, the union of the two rule sets given for suppression will be disabled for the line.

• To suppress rules for a whole file the following must be included before any code is written (i.e. either as the first line of a GAP file, or preceded by any combination of only whitespace, empty lines and comments)::

  gaplint: disable=, , ...

Via a configuration file ^^^^^^^^^^^^^^^^^^^^^^^^

To configure gaplint as in the above examples, create a .gaplint.yml file containing the following lines:

.. code:: yaml

   columns: 100
   indentation: 4
   disable:
   - W002
   - W028

gaplint looks for the .gaplint.yml file in the current directory, and its ancestors, until it reaches a directory containing a git repository or the .gaplint.yml file is located. If there is no .gaplint.yml file, then the default configuration options are used. The options configured in .gaplint.yml are applied to every file on which gaplint is run from the current directory unless overruled higher in the hierarchy.