Re: [PATCH v2 3/4] mergetool--lib: Add functions for finding available tools

[Junio C Hamano <gitster@pobox.com>]

John Keeping <john@keeping.me.uk> writes:

> On Sun, Jan 27, 2013 at 04:52:25PM -0800, David Aguilar wrote:
>> --- a/git-mergetool--lib.sh
>> +++ b/git-mergetool--lib.sh
>> @@ -2,6 +2,35 @@
>>  # git-mergetool--lib is a library for common merge tool functions
>>  MERGE_TOOLS_DIR=$(git --exec-path)/mergetools
>>  
>> +mode_ok () {
>> +	diff_mode && can_diff ||
>> +	merge_mode && can_merge
>> +}
>> +
>> +is_available () {
>> +	merge_tool_path=$(translate_merge_tool_path "$1") &&
>> +	type "$merge_tool_path" >/dev/null 2>&1
>> +}
>> +
>> +show_tool_names () {
>> +	condition=${1:-true} per_line_prefix=${2:-} preamble=${3:-}
>> +
>> +	( cd "$MERGE_TOOLS_DIR" && ls -1 * ) |
>
> Is the '*' necessary here?

No, it was just from a bad habit (I have ls aliased to ls -A or ls
-a in my interactive environment, which trained my fingers to this).

I also think you can lose -1, although it does not hurt.
>> +	tool_opt="'git ${TOOL_MODE}tool --tool-<tool>'"
>> +	available=$(show_tool_names 'mode_ok && is_available' '\t\t' \
>> +		"$tool_opt may be set to one of the following:")
>> +	unavailable=$(show_tool_names 'mode_ok && ! is_available' '\t\t' \
>> +		"The following tools are valid, but not currently available:")
>>  	if test -n "$available"
>>  	then
>> -		echo "'git $cmd_name --tool=<tool>' may be set to one of the following:"
>> -		echo "$available" | sort | sed -e 's/^/	/'
>> +		echo "$available"
>>  	else
>>  		echo "No suitable tool for 'git $cmd_name --tool=<tool>' found."
>>  	fi
>>  	if test -n "$unavailable"
>>  	then
>>  		echo
>> -		echo 'The following tools are valid, but not currently available:'
>> -		echo "$unavailable" | sort | sed -e 's/^/	/'
>> +		echo "$unavailable"
>>  	fi
>>  	if test -n "$unavailable$available"
>>  	then
>
> You haven't taken full advantage of the simplification Junio suggested
> in response to v1 here.  We can change the "unavailable" block to be:
>
>     show_tool_names 'mode_ok && ! is_available' "$TAB$TAB" \
>         "${LF}The following tools are valid, but not currently available:"

Actually I was hoping that we can enhance show_tool_names so that we
can do without the $available and $unavailable variables at all.

> If you also add a "not_found_msg" parameter to show_tool_names then the
> "available" case is also simplified:
>
>     show_tool_names 'mode_ok && is_available' "$TAB$TAB" \
>         "$tool_opt may be set to one of the following:" \
>         "No suitable tool for 'git $cmd_name --tool=<tool>' found."
>
> with this at the end of show_tool_names:
>
>     test -n "$preamble" && test -n "$not_found_msg" && \
>         echo "$not_found_msg"

Yes, something along that line.