3ynm/flymake-quickdef

Quickly define a new Flymake backend

Flymake-Quickdef

Quickly define a new Flymake backend

This package mainly defines flymake-quickdef-backend, a macro which helps remove some of the boilerplate code from defining new Flymake backend functions. The macro defines a function that is suitable to register with Flymake and is similar in implementation to the example in the Flymake manual.

New backend functions using the macro provide, minimally:

1. A Lisp form producing command line arguments for a program
2. A regular expression to search the process output
3. A Lisp form to convert the regex matches into Flymake diagnostics

The process of spawning the process and maintaining temporary files and buffers is generated by the macro. The macro definitions work similarly to Flycheck's macro. This makes it easier to define Flymake diagnostics using external linters and other programs.

Usage

Below is an example Flymake backend produced using the macro. It uses Bandit to check Python source code and shows an example of using a tool which requires a temporary file. The macro handles creating the temporary file to reflect the (possibly unsaved) state of the buffer, running the external process, and cleaning up.

(require 'flymake-quickdef)

(flymake-quickdef-backend flymake-check-bandit
  :pre-let ((bandit-exec (executable-find "bandit")))
  :pre-check (unless bandit-exec (error "Cannot find bandit executable"))
  :write-type 'file
  :proc-form (list bandit-exec "--format" "custom" "--msg-template" "diag:{line} {severity} {test_id}: {msg}" fmqd-temp-file)
  :search-regexp "^diag:\\([[:digit:]]+\\) \\(HIGH\\|LOW\\|MEDIUM\\|UNDEFINED\\) \\([[:alpha:]][[:digit:]]+\\): \\(.*\\)$"
  :prep-diagnostic
  (let* ((lnum (string-to-number (match-string 1)))
         (severity (match-string 2))
         (code (match-string 3))
         (text (match-string 4))
         (pos (flymake-diag-region fmqd-source lnum))
         (beg (car pos))
         (end (cdr pos))
         (type (cond
                ((string= severity "HIGH") :error)
                ((string= severity "MEDIUM") :warning)
                (t :note)))
         (msg (format "%s (%s)" text code)))
    (list fmqd-source beg end type msg)))

Once the backend is defined, just arrange for it to be added to flymake-diagnostic-functions, for example in a mode hook.

Note: if you use flymake-quickdef-backend in a package, always unconditionally (require 'flymake-quickdef), like in the example (not just at compile time). This will ensure that supporting definitions, like global variables, are made when the backend functions run.

License

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

Please see LICENSE.txt for a copy of the license.