inline codeexecution like textmate

EX:

<div id="calender">
</div>
Caret position is after cal - pressing cmd-e (for execute) will make a best guess on what to execute and execute it (executes cal in a background process / terminal and pipes the generated calendar in as a replacement for cal)

this could then be used in all files like this:

<div id="php-version">
</div>

which would then execute php -v to get full version string and place it in the editor.


Also please add basic math features

css files:
b{
left:  10px;
right:10px;
}

Blue shows selection.

b{
left:  10px+144/3;
right:10px+144/3;
}

executing (cmd+e) would then replace selected numbers with the math:


b{
left:  58px;
right:58px;
}