chillaranand/electric-case

[emacs] insert camelCase, snake_case words without "Shift"ing

electric-case.el

camelCase、snake_caseの識別子をShiftキーなしで入力

insert camelCase and snake_case words, without “Shift”ing

Screencast

Installation

Require this script

(require 'electric-case)

and add initialize function to the major-mode hook.

(eval-after-load "cc-mode"
  '(add-hook 'java-mode-hook 'electric-case-java-init))

Now you may type identifiers in lisp-like way,

class class-name
{

:

}

and electric-case will fix it.

class ClassName
{

:

}

Settings for java, c, AHK, Scala are available by default.

electric-case-c-init
electric-case-java-init
electric-case-ahk-init
electric-case-scala-init

Configuration

electric-case-convert-calls

electric-case only fixes declarations, by default. To enable electric-case for all occurrences of identifiers, set “electric-case-convert-calls” non-nil.

(setq electric-case-convert-calls t)

This sometimes produces confusing results, and so is disabled by default. For example,

foo-bar

this is always fixed to

fooBar

even when he meant subtraction.

electric-case-convert-xxxx

Regardless of “electric-case-convert-calls”, hypens around numbers, and hyphens at beginning/end of identifiers are not fixed. That is,

-foo;
foo-3-bar-4;
qux--;

they are not fixed to

Foo;
foo3Bar4;
qux;

You may change this behavior by setting following variables non-nil.

electric-case-convert-beginning
electric-case-convert-nums
electric-case-convert-end

electric-case-pending-overlay

Identifiers that can be fixed are printed in gray. If this is not comfortable for you, set “electric-case-pending-overlay” nil.

(setq electric-case-pending-overlay)

You may also choose another face for the overlay.

(setq electric-case-pending-overlay 'highlight)

Work with Other Languages

Initializing functions (electric-case-xxx-init) actually do set two variables, and turn electric-case-mode on. If you want to use electric-case in other languages, you should configure these two variables in major-mode hooks.

electric-case-criteria

Set a function that defines which case to convert the identifier into. The function will be given two arguments: the beginning/end position of the identifier, that is going to be converted. The function must return one of camel (camelCase), ucamel (UpCamelCase), snake (snake_case), usnake (UP_SNAKE_CASE) or nil. When the return value is nil, fix for the identifier is canceled.

Remember that if “electric-case-convert-calls” is nil, identifiers not in declarations are not expected to be converted. electric-case does not judge if the identifier is in a declaration. So criteria function should return in that case.

Here is an example for C-language.

(setq electric-case-criteria
      (lambda (b e n)
        (let ((proper (text-properties-at b)))
          (cond ((member 'font-lock-function-name-face proper) 'snake)
                ((member 'font-lock-variable-name-face proper)
                 (if (member '(cpp-macro) (c-guess-basic-syntax))
                     'usnake 'snake))
                (electric-case-convert-calls 'snake)
                (t nil)))))

With criteria above, function declarations and variable declarations are converted into snake_case. Macro declarations are converted into UP_SNAKE_CASE.

electric-case-max-iteration

For example, in Java, the syntactical category of the symbol “what-is-this” below is not decidable currently.

class MyClass{
    what-is-this
}

But when “symbol;” is added, now “what-is-this” is a name of a class.

class MyClass{
    what-is-this symbol;
}

So electric-case can fix it into UpCamelCase.

class MyClass{
    WhatIsThis symbol;
}

In the example above, the symbol “what-is-this” should be checked twice or more. Otherwise, “what-is-this” is not fixed. Then “electric-case-max-iteration” should be 2 or greater.

Known Bugs and Limitations

• In java, class names that end with “Class” are not fixed correctly