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https://github.com/fish-shell/fish-shell.git
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827bce6c88
mandoc users do not need to install nroff to be able to format and view manual pages. If both nroff and mandoc cannot be found it will show an error.
100 lines
3.6 KiB
Fish
100 lines
3.6 KiB
Fish
function __fish_print_help --description "Print help message for the specified fish function or builtin" --argument item
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if test "$item" = '.'
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set item source
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end
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# Do nothing if the file does not exist
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if not test -e "$__fish_data_dir/man/man1/$item.1" -o -e "$__fish_data_dir/man/man1/$item.1.gz"
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return
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end
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# Render help output, save output into the variable 'help'
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set -l help
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set -l format
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set -l cols
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if test -n "$COLUMNS"
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set cols (math $COLUMNS - 4) # leave a bit of space on the right
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end
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# Pick which command we are using to render output or fail if none
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if command -qs nroff
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set format nroff -c -man -t
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if test -e $__fish_data_dir/groff/fish.tmac
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set -a format -M$__fish_data_dir/groff -mfish
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end
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if test -n "$cols"
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set -a format -rLL={$cols}n
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end
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else if command -qs mandoc
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set format mandoc -c
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if test -n "$cols"
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set -a format -O width=$cols
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end
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else
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echo fish: (_ "Cannot format help; no parser found")
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return 1
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end
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if test -e "$__fish_data_dir/man/man1/$item.1"
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set help ($format "$__fish_data_dir/man/man1/$item.1" 2>/dev/null)
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else if test -e "$__fish_data_dir/man/man1/$item.1.gz"
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set help (gunzip -c "$__fish_data_dir/man/man1/$item.1.gz" 2>/dev/null | $format 2>/dev/null)
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end
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# The original implementation trimmed off the top 5 lines and bottom 3 lines
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# from the nroff output. Perhaps that's reliable, but the magic numbers make
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# me extremely nervous. Instead, let's just strip out any lines that start
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# in the first column. "normal" manpages put all section headers in the first
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# column, but fish manpages only leave NAME like that, which we want to trim
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# away anyway.
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#
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# While we're at it, let's compress sequences of blank lines down to a single
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# blank line, to duplicate the default behavior of `man`, or more accurately,
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# the `-s` flag to `less` that `man` passes.
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set -l state blank
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for line in $help
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# categorize the line
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set -l line_type
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switch $line
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case ' *' \t\*
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# starts with whitespace, check if it has non-whitespace
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printf "%s\n" $line | read -l word __
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if test -n $word
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set line_type normal
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else
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# lines with just spaces probably shouldn't happen
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# but let's consider them to be blank
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set line_type blank
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end
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case ''
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set line_type blank
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case '*'
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# not leading space, and not empty, so must contain a non-space
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# in the first column. That makes it a header/footer.
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set line_type meta
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end
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switch $state
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case normal
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switch $line_type
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case normal
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printf "%s\n" $line
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case blank
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set state blank
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case meta
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# skip it
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end
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case blank
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switch $line_type
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case normal
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echo # print the blank line
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printf "%s\n" $line
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set state normal
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case blank meta
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# skip it
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end
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end
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end | ul # post-process with `ul`, to interpret the old-style grotty escapes
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echo # print a trailing blank line
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end
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