fish-shell/share/functions/__fish_print_help.fish
2019-04-21 09:07:29 -07:00

107 lines
4 KiB
Fish

function __fish_print_help --description "Print help message for the specified fish function or builtin" --argument item
if test "$item" = '.'
set item source
end
# Do nothing if the file does not exist
if not test -e "$__fish_data_dir/man/man1/$item.1" -o -e "$__fish_data_dir/man/man1/$item.1.gz"
return
end
# Render help output, save output into the variable 'help'
set -l help
set -l format
set -l cols
if test -n "$COLUMNS"
set cols (math $COLUMNS - 4) # leave a bit of space on the right
end
# Pick which command we are using to render output or fail if none
if command -qs nroff
set format nroff -c -man -t
if test -e $__fish_data_dir/groff/fish.tmac
set -a format -M$__fish_data_dir/groff -mfish
end
if test -n "$cols"
set -a format -rLL={$cols}n
end
else if command -qs mandoc
set format mandoc -c
if test -n "$cols"
set -a format -O width=$cols
end
else
echo fish: (_ "Cannot format help; no parser found")
return 1
end
if test -e "$__fish_data_dir/man/man1/$item.1"
set help ($format "$__fish_data_dir/man/man1/$item.1" 2>/dev/null)
else if test -e "$__fish_data_dir/man/man1/$item.1.gz"
set help (gunzip -c "$__fish_data_dir/man/man1/$item.1.gz" 2>/dev/null | $format 2>/dev/null)
end
# 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
set -l have_name
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 '*'
# Remove man's bolding
set -l name (string replace -ra '(.)'\b'.' '$1' -- $line)
# We start after we have the name
contains -- $name NAME; and set have_name 1; and continue
# We ignore the SYNOPSIS header
contains -- $name SYNOPSIS; and continue
# Everything after COPYRIGHT is useless
contains -- $name COPYRIGHT; and break
# 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
set -q have_name[1]; or continue
switch $state
case normal
switch $line_type
case normal meta
printf "%s\n" $line
case blank
set state blank
end
case blank
switch $line_type
case normal meta
echo # print the blank line
printf "%s\n" $line
set state normal
case blank meta
# skip it
end
end
end | string replace -ra '^ ' '' | ul # post-process with `ul`, to interpret the old-style grotty escapes
end