Clickable terminal patterns

libvte9 includes the ability to tell its clients if a particular position is within a match to any of a list of regexps; this ability is used by gnome-terminal and xfce4-terminal to make links in terminals clickable.

However, the list of regexps is hardcoded. It would be useful to add additional regexps, for reasons like the following:

• Clicking on grep -n output like "./terminal/terminal-widget.c:292:" could request Emacs to open the file at the line in question.
• Clicking on a company-internal bug number like "ITN-6748" could open the URL of the ticket in question.
• Clicking on a date could open your favorite calendar app to that date.
• Clicking on a Bitcoin address could open your Bitcoin client to send Bitcoins to its owner.
• Clicking on an IP address could prompt you with various things to do: mtr, nmap, reverse DNS lookup, etc.
• Clicking on a street address could search for it in Google Maps.
• Clicking on a Twitter @username could open their Twitter page.
• Clicking on a DOI number could look it up in a way appropriate to your campus.
• Clicking on a phone number could call it, add it to your address book, or look it up in your address book.

These suggest a configuration file with a syntax like

/home/paul/bin/open-ticket ITN-[[:digit:]]+
/home/paul/bin/open-editor ^[./][^ ]*:[[:digit:]]+:
/home/paul/bin/open-calendar \<[[:digit:]]{4}-[[:digit:]]{2}-[[:digit:]]{2}\>

where the scripts alluded to will be invoked with the matched string as an argument. open-editor could be implemented, for example, as follows:

#!/bin/sh
exec >"$HOME/editor.log" 2>&1
IFS=:
set $1
emacsclient +$2 $1 &

In the case of xfce-terminal, this would involve:

1. Dynamically allocating new pattern types when reading this file, in addition to the four predefined ones at terminal/terminal-widget.c:65.

2. Adding the new regexes to the libvte widget, along with the ones from regex_patterns at terminal/terminal-widget.c:78, in terminal_widget_update_highlight_urls at terminal/terminal-widget.c:772.

3. Perhaps factoring the two calls to vte_terminal_match_check in terminal_widget_context_menu at terminal/terminal-widget.c:292 and in terminal_widget_button_press_event at terminal/terminal-widget.c:403 into a single thing? In any case, wire them both up to invoke a new function to invoke the user-defined action.

4. Writing the new user-defined action function, which would spawn off a subprocess with the requested command.