My friend and co-worker Panos Astithas was in town the other day, and so
we decided to hack together on some features that we wouldn't normally be
working on in our regular day-to-day. Among them was a new evaluation feature
for the Firefox Developer Tools' Scratchpad that allows you to
evaluate individual top level functions at a time. The command is bound to the
Cmd + E keyboard shortcut and was inspired by SLIME's
slime-compile-defun (C-c C-c) command.
Being able to re-evaluate individual functions at a time enables faster
prototyping. The previous workflow whenever you wanted to edit functions was to
refresh the app, repeat interactions that put the app back into the previous
state, and then finally observe how your changes affected the app. In many
cases, you can avoid this lengthy process by editing your code in the Scratchpad
Cmd + E to re-evaluate individual functions. Re-evaluating
individual functions doesn't refresh the app, and lets it maintain its existing
state. No refreshing or repeated interactions required.
When you re-evaluate a function with
Cmd + E, we flash the function's source
text briefly to provide some visual feedback.
This feature is available in Firefox 28, which is currently in the Nightly release channel.