Send selected lines to Espruino

Actually, if you go to Editor Key Shortcuts in Settings, you'll see:

Shift + ENTER
Upload just the text that is selected in the editor pane

So that should do exactly what you want? It's not a specific button but just a keypress, but still...

I guess another option is to have the snippets option be able to check the contents of the current editor file for comments of a special form:

/* SNIPPETS
Water Plants : turnWaterPumpOn();
Reset : reset();
*/

Might work?