fish-shell/share/functions/__fish_print_help.fish
Sanne Wouda cad1dc5293 Fix #1978:"ul: unknown escape sequence" when asking for help
It seems that `ul` can't handle the escape sequences for bold text that `nroff` generates on my system.  Fixed by either removing `| ul`, or adding `-c` to the `nroff` command.

Needs testing for old (OSX?) versions of nroff.
2015-04-04 12:03:58 -07:00

100 lines
2.8 KiB
Fish

function __fish_print_help --description "Print help message for the specified fish function or builtin" --argument item
# special support for builtin_help_get()
set -l tty_width
if test "$item" = "--tty-width"
set tty_width $argv[2]
set item $argv[3]
end
if test "$item" = '.'
set item source
end
# Do nothing if the file does not exist
if not test -e "$__fish_datadir/man/man1/$item.1"
return
end
set -l IFS \n\ \t
# Render help output, save output into the variable 'help'
set -l help
set -l cols
set -l rLL
if test "$tty_width" -gt 0
set cols $tty_width
else if command test -t 1
# We want to simulate `man`'s dynamic line length, because
# defaulting to 80 kind of sucks.
# Note: using `command test` instead of `test` because `test -t 1`
# doesn't seem to work right.
# Note: grab the size from the stdout terminal in case it's somehow
# different than the stdin of fish.
# use fd 3 to copy our stdout because we need to pipe the output of stty
begin
stty size 0<&3 | read __ cols
end 3<&1
end
if test -n "$cols"
set cols (expr $cols - 4) # leave a bit of space on the right
set rLL -rLL=$cols[1]n
end
set help (nroff -man -c -t $rLL "$__fish_datadir/man/man1/$item.1" ^/dev/null)
# The original implementation trimmed off the top 5 lines and bottom 3 lines
# from the nroff output. Perhaps that's reliable, but the magic numbers make
# me extremely nervous. Instead, let's just strip out any lines that start
# in the first column. "normal" manpages put all section headers in the first
# column, but fish manpages only leave NAME like that, which we want to trim
# away anyway.
#
# While we're at it, let's compress sequences of blank lines down to a single
# blank line, to duplicate the default behavior of `man`, or more accurately,
# the `-s` flag to `less` that `man` passes.
set -l state blank
for line in $help
# categorize the line
set -l line_type
switch $line
case ' *' \t\*
# starts with whitespace, check if it has non-whitespace
printf "%s\n" $line | read -l word __
if test -n $word
set line_type normal
else
# lines with just spaces probably shouldn't happen
# but let's consider them to be blank
set line_type blank
end
case ''
set line_type blank
case '*'
# not leading space, and not empty, so must contain a non-space
# in the first column. That makes it a header/footer.
set line_type meta
end
switch $state
case normal
switch $line_type
case normal
printf "%s\n" $line
case blank
set state blank
case meta
# skip it
end
case blank
switch $line_type
case normal
echo # print the blank line
printf "%s\n" $line
set state normal
case blank meta
# skip it
end
end
end | ul # post-process with `ul`, to interpret the old-style grotty escapes
echo # print a trailing blank line
end