/gaplint

A linter for GAP (https://www.gap-system.org/)

Primary LanguagePythonGNU General Public License v3.0GPL-3.0

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.

Code Name Description
W000 analyse-lvars Warns if there are declared local variables that are not used or assigned but not used or if there are unused function arguments.
W001 empty-lines Warns if there are consecutive empty lines.
W002 line-too-long Warns if there is a line which is longer than the configured maximum (defaults to 80)
W003 indentation Warns if a line is under indented.
W004 align-assignments Warns if there are assignments in consecutive lines that are not aligned.
W005 align-trailing-comments Warns if there are trailing comments in consecutive lines that are not aligned.
W006 align-comments Warns if there are non-trailing comments in consecutive lines that are not aligned
W007 trailing-whitespace Warns if there is trailing whitespace at the end of a line
W008 no-space-after-comment Warns if there is no space after any number of # is a line
W009 not-enough-space-before-comment Warns if there is not enough space before the first # in any line (defaults to 2)
W010 space-after-comma Warns if a comma is followed by more than 1 space
W011 space-before-comma Warns if a comma is preceded by a space
W012 space-after-bracket Warns if there is a space after an opening bracket
W013 space-before-bracket Warns if there is a space before a closing bracket
W014 multiple-semicolons Warns if there is more than one semicolon in a line
W015 keyword-function Warns if the keyword function is not followed by an open bracket
W016 whitespace-op-assign Warns if there is not exactly 1 space after an assignment (:=)
W017 tabs Warns if there are tabs
W018 function-local-same-line Warns if the keywords function and local appear in the same line
W019 whitespace-op-minus Warns if there is not exactly 1 space either side of a minus (-) operator
W020 whitespace-op-plus Warns if there is not exactly 1 space either side of a plus (+) operator
W021 whitespace-op-multiply Warns if there is not exactly 1 space either side of a multiply (*) operator
W022 whitespace-op-negative Warns if there is not exactly 1 space preceding a negative (-) operator
W023 whitespace-op-less-than Warns if there is not exactly 1 space either side of a less-than (<) operator
W024 whitespace-op-less-equal Warns if there is not exactly 1 space either side of a less-than / equal-to (<=) operator
W025 whitespace-op-more-than Warns if there is not exactly 1 space either side of a greater-than(>) operator
W026 whitespace-op-more-equal Warns if there is not exactly 1 space either side of greater than or equal to (>=) operator
W027 whitespace-op-equals Warns if there is not exactly 1 space either side of equals (=) operator
W028 whitespace-op-mapping Warns if there is not exactly 1 space either side of mapping (->) operator
W029 whitespace-op-divide Warns if there is not exactly 1 space either side of divide (/) operator
W030 whitespace-op-power Warns if there is not exactly 1 space either side of the power (^) operator
W031 whitespace-op-not-equal Warns if there is not exactly 1 space either side of not-equal (<>) operator
W032 whitespace-op-double-dot Warns if there is not exactly 1 space either side of arithmetic progression (..) operator
W033 assign-then-return Warns if a variable is assigned and then immediately returned
W034 1-line-function Warns that one line functions can be lambdas
W035 pointless-lambda Warns when there are lambda functions of the form x -> f(x) which can be replaced by f
W036 use-return-true Warns that x -> true can be replaced by ReturnTrue
W037 use-return-false Warns that x -> false can be replaced by ReturnFalse
W038 use-return-fail Warns that x -> fail can be replaced by ReturnFail
W039 use-remove-not-unbind Warns that Unbind(x[Length[x]]) can be replaced by Remove(x)

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.
  • max-warnings: maximum number of warnings before gaplint aborts. Defaults to 1000.
  • indentation: minimum indentation of nested statements. Defaults to 2.
  • disable: rules can be disabled using their name or code. Defaults to no rules disabled.

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 a hierarchy described below. A preference given somewhere higher on the hierarchy than another will be given precedence. Disabled rules accumulate through the hierarchy.

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=<name_or_code>, <name_or_code> ...

  • 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)=<name_or_code>, <name_or_code>, ...

  • 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=<name_or_code>, <name_or_code>, ...

Via a configuration file

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

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.