This attempts to support a simple formatting and intentation style for
plain sh syntax (and other sh-compatible code which doesn't stray too
far from portable sh).
The complexity of sh syntax means that we have to be opinionated -
attempting to be more flexible would require extensive context
awareness, and would require something more akin to a proper
autoformatting tool or a language server.
The formatting style used here makes use of vertical whitespace as the
primary delimiter, so that code ends up looking like this:
if [ $foo = "bar" ]; then
thing1
else
thing2
fi
for i in foo bar baz; do
thing1
thing2
done
case "$foo" in
bar) thing1;;
baz)
thing1
thing2
;;
esac
Since the formatting style used is very opinionated the 'sh_auto_indent'
option can be used to disable auto-indentation, with the default set to
'no'.
Due to ambiguity in the POSIX standard, GNU and BSD versions of the `wc`
utility use slightly different whitespace conventions when formatting
their output [1]. When limiting the output to just counting the number
of bytes (as is done by Kakoune when calculating the length of words
for spell check highlighting), the BSD version of `wc -c` has some
additional leading whitespace:
gnu$ printf %s "test" | wc -c
4
bsd$ printf %s "test" | wc -c
4
This leading whitespace needs to be removed before defining the "region"
to highlight, or `set-option` will not be able to parse the given
`spell_regions` and will complain that there are "not enough elements
in tuple." In other words, the region `1.21+8|Error` on Linux ends up
looking like `1.21+ 8|Error` on macOS, which is invalid.
Removing the whitespace could be accomplished in a number of ways, but
using arithmetic expansion [2] is POSIX compliant and does not require
shelling out to another process.
[1]: https://unix.stackexchange.com/questions/205906/extra-space-with-counted-line-number
[2]: https://mywiki.wooledge.org/ArithmeticExpression
