lisp-extra-font-lock - Highlight bound variables and quoted exprs

Author: Anders Lindgren
Version: 0.0.6
URL: https://github.com/Lindydancer/lisp-extra-font-lock

This package highlight the location where local variables is created (bound, for example by let) as well as quoted and backquoted constant expressions.

Example

Below, ^ is used indicate highlighted normal variables and constant expressions. * is used to show highlighting of special variables (i.e. those defined by defvar) and of the backquote and comma operators.

(defun my-function (next)
                    ^^^^             <- Parameters
  (let ((numbers '(one two three))
         ^^^^^^^  ^^^^^^^^^^^^^^^    <- Var bound by `let` and quoted expr.
        (buffer-read-only t))
         ****************            <- Special variable (different color)
    `(,@numbers and ,next)))
    *^**        ^^^ *    ^           <- Backquote and comma

Screenshot

What is highlighted

• Parameters in functions and lambdas
• Variables bound by specal constructs like let, dolist, condition-case, and pcase-let
• Normal variables and variables declared as globals using defvar are highlighted in different colors, as a warning
• Quoted expressions
• Backquoted expressions. Subexpressions using the "," or ",@" are not highlighted (as they are evaluted and thus not constant). Also, the backquote and the comma operators themselves are highlighted using a bright color as a warning.
• Hash-quoted symbols.

Installation

Place this package in a directory in the load-path. To activate it, use customize or place the following lines in a suitable init file:

   (require 'lisp-extra-font-lock)
   (lisp-extra-font-lock-global-mode 1)

Customization

You can modify the following lists to add more functions that are recognized:

• lisp-extra-font-lock-let-functions -- List of function with the same syntax as let
• lisp-extra-font-lock-defun-functions -- List of function with the same syntax as defun
• lisp-extra-font-lock-lambda-functions -- List of function with the same syntax as lambda
• lisp-extra-font-lock-dolist-functions -- List of function with the same syntax as dolist
• lisp-extra-font-lock-bind-first-functions -- List of function that bind their first argument, like condition-case.
• lisp-extra-font-lock-loop-functions -- List of functions with the same syntax as cl-loop.

The following faces are used when highlighting. You can either redefine the face (e.g. using a theme), or you can rebind the corresponding variable.

• Local variables are highlighted using the standard face font-lock-variable-name-face
• Special (global) variables that are rebound are highlighted using the face bound to the variable lisp-extra-font-lock-special-variable-name-face (by default lisp-extra-font-lock-special-variable-name, which inherits from font-lock-warning-face)
• Quoted expressions use the face bound to the variable lisp-extra-font-lock-quoted-face (by default lisp-extra-font-lock-quoted, which inherits from font-lock-constant-face)
• The backquote and comma operators use the face bound to the variable lisp-extra-font-lock-backquote-face (by default lisp-extra-font-lock-backquote, which inherits from font-lock-warning-face).
• Named arguments to cl-loop are highlighted using font-lock-builtin-face.

Example

To set the face used to highlight quoted expressions to a gray color, you can use:

    (custom-set-faces
      '(lisp-extra-font-lock-quoted ((t :foreground "grey50"))))

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Converted from lisp-extra-font-lock.el by el2markdown.