Option lists and maps are specified using separate arguments, avoiding
the need for additional escaping of their separator and reusing the
existing command line spliting logic instead.
As discussed on #2087, this should make it much easier to work with
list options, and make the general option system feel cleaner.
Command line parsing now works as follow:
* Quoted strings ('...', "..." and %~...~ with '~' non nestable)
use 'doubling-up' for escaping their delimiter, if the delimiter
appears twice in a row, it is considered as part of the string and
represent one delimiter character. So 'abc''def' == "abc'def". No
other escaping takes place in those strings.
* Balanced strings (%{...}) do not support any kind of escaping, but
finds the matching closing delimiter by taking nesting into account.
So %{abc{def}} == "abc{def}".
* Non quoted words support escaping of `;` and whitespaces with `\`,
`%`, `'` and '"` can be escaped with `\` at the start of the word,
they do not need escaping (and will not be escaped) else where in
a word where they are treated literally. Any other use of '\' is a
literal '\'. So \%abc%\;\ def == "%abc%; def"
As discussed in #2046 this should make our command line syntax more
robust, provide a simple programmatic way to escape a string content
(s/<delim>/<delim><delim>/g), be well defined instead of ad-hoc
undocumented behaviour, and interact nicely with other common
escaping by avoiding escaping hell (:grep <regex> can in most case
be written with the regex unquoted).
Automatic reparsing of %sh{...}, while convenient in many cases,
can be surprising as well, and can lead to security problems:
'echo %sh{ printf "foo\necho bar" }' runs 'echo foo', then 'echo bar'.
we make this danger explicit, and we fix the 'nop %sh{...}' pattern.
To reparse %sh{...} strings, they can be passed to evaluate-commands,
which has been fixed to work in every cases where %sh{...} reparsing
was used..
I dedicate any and all copyright interest in this software to the
public domain. I make this dedication for the benefit of the public at
large and to the detriment of my heirs and successors. I intend this
dedication to be an overt act of relinquishment in perpetuity of all
present and future rights to this software under copyright law.
Note: `GNU/screen` has a different interpretation of what constitutes
a "vertical split", hence the inverted command descriptions, compared
to the tmux/iterm etc.
Closes#1626
