From 761fd7247a77f550a5083ca8cbd430909f773bd5 Mon Sep 17 00:00:00 2001
From: Tom Ryder <tom@sanctum.geek.nz>
Date: Thu, 26 Nov 2015 18:15:58 +1300
Subject: Experimental man(1) completion

---
 bash/bashrc.d/man.bash | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 65 insertions(+)
 create mode 100644 bash/bashrc.d/man.bash

diff --git a/bash/bashrc.d/man.bash b/bash/bashrc.d/man.bash
new file mode 100644
index 00000000..4994c379
--- /dev/null
+++ b/bash/bashrc.d/man.bash
@@ -0,0 +1,65 @@
+# Autocompletion for man(1)
+_man() {
+
+    # Don't even bother if we don't have manpath(1)
+    hash manpath || return 1
+
+    # Snarf the word
+    local word
+    word=${COMP_WORDS[COMP_CWORD]}
+
+    # If this is the second word, and the previous word was a number, we'll
+    # assume that's the section to search
+    local section 
+    if ((COMP_CWORD > 1)) && [[ ${COMP_WORDS[COMP_CWORD-1]} != [^0-9] ]] ; then
+        section='man'${COMP_WORDS[COMP_CWORD-1]}
+    fi
+
+    #
+    # Read newline-separated output from a subshell into the COMPREPLY array.
+    #
+    # This is subtly wrong. Given that it's just a path, there's theoretically
+    # no reason that the name of a man(1) page couldn't contain a newline. If
+    # one of them does, then this method will include some junk manual page
+    # names. But who on earth makes a manual page with a newline in the name?
+    #
+    # Using null separators doesn't work, because read prioritises reading the
+    # end of the line before it does field-splitting, and filling COMPREPLY
+    # entry-by-entry is *really* slow, so this is the least-wrong solution I
+    # could come up with that allows me to use a subshell to elegantly set
+    # globbing shell options.
+    #
+    IFS=$'\n' read -a COMPREPLY -d '' -r < <(
+
+        # Don't return dotfiles, and expand empty globs to just nothing
+        shopt -u dotglob
+        shopt -s nullglob
+
+        # Start an array of pages
+        declare -a pages
+
+        # Break manpath(1) output into an array of paths
+        IFS=: read -a manpaths -r < <(manpath)
+
+        # Iterate through the manual page paths and add every manual page we find
+        for manpath in "${manpaths[@]}" ; do
+            [[ $manpath ]] || continue
+            pages=("${pages[@]}" "$manpath"/"$section"*/"$word"*)
+        done
+
+        # Strip paths, .gz suffixes, and finally .<section> suffixes
+        pages=("${pages[@]##*/}")
+        pages=("${pages[@]%.gz}")
+        pages=("${pages[@]%.*}")
+
+        # Bail out if we ended up with no pages somehow to prevent us from
+        # printing
+        ((${#pages[@]})) || exit 1
+
+        # Print the pages array to stdout, newline-separated; see above
+        # explanation
+        (IFS=$'\n' ; printf %s "${pages[*]}")
+    )
+}
+complete -F _man -o default man
+
-- 
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