matatu blog

Whitespace Characters and Coding

On the presence or absence of whitespace in code.

Part 1: Types of whitespace

$ raku -e 'say " ".uniname'
SPACE
$ raku -e 'say " ".ord'
32
$ raku -e 'say " ".ord.fmt("%x")'
20

ASCII 32, hex 0x20 is the space character.

There is also tab of course.

$ raku -e 'say "\t".ord.fmt("%x")'
9
$ raku -e 'say "\t".ord'
9
$ raku -e 'say "\t".uniname'
<control-0009>

Okay, I guess it's also called control-0009.

Moving on, we have the ubiquitous carriage return.

~ $ raku -e 'say "\n".uniname'
<control-000A>

which is different on half the computers in the world

$ raku -e 'say "\r\n".uninames'
(<control-000D> <control-000A>)

and I think is a neat example of how to count characters. Put these two together and you still only have one "character".

raku -e 'say "\r\n".chars'
1

What do these all have in common?

~ $ raku -e 'say " ".uniprops("White_Space")'
(True)
~ $ raku -e 'say "\t".uniprops("White_Space")'
(True)
~ $ raku -e 'say "\r\n".uniprops("White_Space")'
(True True)

They all have the "White_Space" unicode property.

So, what else has that property?

say (.fmt("%5d"),.fmt("0x%04x"),.uniname)
  for (0..0x10fff).grep: *.uniprop("White_Space")

(    9 0x0009 <control-0009>)
(   10 0x000a <control-000A>)
(   11 0x000b <control-000B>)
(   12 0x000c <control-000C>)
(   13 0x000d <control-000D>)
(   32 0x0020 SPACE)
(  133 0x0085 <control-0085>)
(  160 0x00a0 NO-BREAK SPACE)
( 5760 0x1680 OGHAM SPACE MARK)
( 8192 0x2000 EN QUAD)
( 8193 0x2001 EM QUAD)
( 8194 0x2002 EN SPACE)
( 8195 0x2003 EM SPACE)
( 8196 0x2004 THREE-PER-EM SPACE)
( 8197 0x2005 FOUR-PER-EM SPACE)
( 8198 0x2006 SIX-PER-EM SPACE)
( 8199 0x2007 FIGURE SPACE)
( 8200 0x2008 PUNCTUATION SPACE)
( 8201 0x2009 THIN SPACE)
( 8202 0x200a HAIR SPACE)
( 8232 0x2028 LINE SEPARATOR)
( 8233 0x2029 PARAGRAPH SEPARATOR)
( 8239 0x202f NARROW NO-BREAK SPACE)
( 8287 0x205f MEDIUM MATHEMATICAL SPACE)
(12288 0x3000 IDEOGRAPHIC SPACE)

A practical character from these is the "NO-BREAK SPACE"; a pithy alternative to   or <nobr>.

Putting some positive space next to the negative space makes it easier to distinguish them.

 say ("\c[FULL BLOCK]{.chr}\c[FULL BLOCK]",.uniname)
     for (0..0x10fff).grep: *.uniprop("White_Space")

(█      █ <control-0009>)
(█
█ <control-000A>)
(█
  █ <control-000B>)
(██ <control-000C>)
█ <control-000D>)
(█ █ SPACE)
(█
█ <control-0085>)
(█ █ NO-BREAK SPACE)
(█ █ OGHAM SPACE MARK)
(█ █ EN QUAD)
(█ █ EM QUAD)
(█ █ EN SPACE)
(█ █ EM SPACE)
(█ █ THREE-PER-EM SPACE)
(█ █ FOUR-PER-EM SPACE)
(█ █ SIX-PER-EM SPACE)
(█ █ FIGURE SPACE)
(█ █ PUNCTUATION SPACE)
(█ █ THIN SPACE)
(█ █ HAIR SPACE)
(█
█ LINE SEPARATOR)
(█
█ PARAGRAPH SEPARATOR)
(█ █ NARROW NO-BREAK SPACE)
(█ █ MEDIUM MATHEMATICAL SPACE)
(█　█ IDEOGRAPHIC SPACE)    

We can also remove space with the zero width joiner.

The zero width joiner is not whitespace.

raku -e 'say "\c[ZERO WIDTH JOINER]".uniprops("White_Space")'
(False)

This is not to be confused with the zero-width space, which is also not whitespace. The zero width space and no-break space give you fine-grained control over exactly where your browser decides to split up your words when doing word-wrapping. But let's look at the joiner first:

say "\c[MAN]\c[ARTIST PALETTE]"
# 👨🎨

say "\c[MAN]​\c[ZERO WIDTH JOINER]​\c[ARTIST PALETTE]"
# 👨‍🎨    

Conclusions

In part 2, we look at the use of whitespace, non-white space, and unspacing in several programming languages.