Sounds good but I don't see anything about bookmarks in the API documentation.
In the same line of thinking, the search could be done over the current syntax scope (ctrl-shift-space) or the current bracket scope (ctrl-shift-m), but those scopes are not always useful. A 'current function scope' would be nicer.
Sounds like a fair alternative... I'll try that.
The two outer selections must be empty and will delimit the search area.
The middle selection will be used as a search pattern; if it's an empty selection, the whole word will be used.