Commify

Insert or remove grouping commas (or other grouping character) in the number under or adjacent to the cursor, or for all numbers within the region, with a single command. This is an otherwise tedious chore and one that is not easily done via a macro or other Emacs user-level facilities.

Installation

Without Package

Add commify.el to your load-path and

(require 'commify)

With Package Manager

Simply install the commify package.

Configuration

Commify has several variables that you can set to alter its behaviour, either through the Emacs customize facility or with setq’s in your init file.

Variables controlling decimal numbers

The following variables affect how commify treats decimal numbers:

commify-group-char

set this to a one-character string for inserting between groups of digits. By default it is set to “,”.

commify-group-size

set this to an integer specifying the number of decimal digits you want in each group. By default this is set to 3.

commify-decimal-char

set this to a one-character string that is recognized as the decimal point. By default this is set to “.”.

Variables controlling hexadecimal numbers

The following variables affect how commify treats numbers in other bases:

commify-hex-enable

set non-nil to enable grouping on hexadecimal numbers. By default it is set to t.

commify-hex-group-char

set this to a string for inserting between groups of hexadecimal digits. By default it is set to “_”.

commify-hex-group-size

set this to an integer specifying the number of hexadecimal digits you want in each group. By default this is set to 4.

commify-hex-prefix-re

set to a string regular expression that matches the beginning of a string by which hexadecimal numbers can be recognized. By default it is set to “0[xX]”

commify-hex-digits

set to a string that represents a character class (without the square brackets) of valid hexadecimal digits. This is not itself a regular expression, but is used to build one to recognize hexadecimal numbers. By default it is set to “0-9A-Fa-f”.

commify-hex-suffix-re

set to a string regular expression that matches the end of a string by which hexadecimal numbers can be recognized. By default it is set to “”

Variables controlling octal numbers

Similar variables control commify’s treatment of octal numbers:

commify-oct-enable

set non-nil to enable grouping on octal numbers. By default it is set to t.

commify-oct-group-char

set this to a string for inserting between groups of octal digits. By default it is set to “_”.

commify-oct-group-size

set this to an integer specifying the number of octal digits you want in each group. By default this is set to 2.

commify-oct-prefix-re

set to a string regular expression that matches the beginning of a string by which octal numbers can be recognized. By default it is set to “0[oO]”

commify-oct-digits

set to a string that represents a character class (without the square brackets) of valid octal digits. This is not itself a regular expression, but is used to build one to recognize octal numbers. By default it is set to “0-7”.

commify-oct-suffix-re

set to a string regular expression that matches the end of a string by which octal numbers can be recognized. By default it is set to “”

Variables controlling binary numbers

And, finally, another set of variables control commify’s treatment of binary numbers:

commify-bin-enable

set non-nil to enable grouping on binary numbers. By default it is set to t.

commify-bin-group-char

set this to a string for inserting between groups of binary digits. By default it is set to “_”.

commify-bin-group-size

set this to an integer specifying the number of binary digits you want in each group. By default this is set to 4.

commify-bin-prefix-re

set to a string regular expression that matches the beginning of a string by which binary numbers can be recognized. By default it is set to “0[bB]”.

commify-bin-digits

set to a string that represents a character class (without the square brackets) of valid binary digits. This is not itself a regular expression, but is used to build one to recognize binary numbers. By default it is set to “0-1”.

commify-bin-suffix-re

set to a string regular expression that matches the end of a string by which binary numbers can be recognized. By default it is set to “”

Keybindings

Bind the commify-toggle command to a convenient key. I have put it on the “,,” keychord since it is rare in English to type two commas in a row.

(key-chord-define-global ",," 'commify-toggle)

You may also want to change the default settings:

(setq commify-group-char "_")
(setq commify-decimal-char ",")
(setq commify-group-size 4)
(setq commify-bin-group-size 8)
(key-chord-define-global ",," 'commify-toggle)

Usage

When editing a buffer, simply put your cursor before, after, or within a number, integer, or decimal, then invoke the command.

The factorial of 15 is 1307674368000.

With the cursor anywhere in or immediately adjacent to the number, hit “,,” (or whatever you’ve bound the commify-toggle command to) and the buffer will change to:

The factorial of 15 is 1,307,674,368,000.

If you invoke the command again, the commas are removed. commify-toggle works on floating or scientific numbers as well, but it only ever affects the digits before the decimal point as defined in the commify-decimal-char variable.

Afterwards, the cursor will be moved to the point immediately after the affected number.

Ignored Numbers

If a number appears to be (1) part of a date, (2) part of an identifier, or (3) a decimal number starting with zero, commify will ignore it. Thus, if the cursor is to the left of ‘2012-09-22’ invoking commify-toggle will leave the text alone, but will still advance the cursor.

Acting on the Region

If the region is active when the you invoke commify-toggle, all numbers in the region have commify-toggle invoked on them. This can be especially handy when you want to commify numbers in a org-mode table, for example.

With the following table set as the region:

|      Decimal | Binary                                     | Octal           |          Hex |
|--------------+--------------------------------------------+-----------------+--------------|
|   4207868622 | 0b11111010110011101111101011001110         | 0o37263575316   |   0xFACEFACE |
|   2882343476 | 0b10101011110011010001001000110100         | 0o25363211064   |   0xABCD1234 |
|   3405695742 | 0b11001010111111101100101011111110         | 0o31277545376   |   0xCAFECAFE |
| 802549529294 | 0b1011101011011011101011011111101011001110 | 0o3533353375316 | 0xBADBADFACE |

Running commify-toggle on the region yields:

| Decimal         | Binary                                              | Octal                 | Hex            |
|-----------------+-----------------------------------------------------+-----------------------+----------------|
| 4,207,868,622   | 0b1111_1010_1100_1110_1111_1010_1100_1110           | 0o3_72_63_57_53_16    | 0xFACE_FACE    |
| 2,882,343,476   | 0b1010_1011_1100_1101_0001_0010_0011_0100           | 0o2_53_63_21_10_64    | 0xABCD_1234    |
| 3,405,695,742   | 0b1100_1010_1111_1110_1100_1010_1111_1110           | 0o3_12_77_54_53_76    | 0xCAFE_CAFE    |
| 802,549,529,294 | 0b1011_1010_1101_1011_1010_1101_1111_1010_1100_1110 | 0o3_53_33_53_37_53_16 | 0xBA_DBAD_FACE |

Not much to it, but it saves me a lot of time.