gaplint 1.2.0

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

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.