[code] [textadept] The UPDATE_UI event

From: Hugh Low <hughlow3.att.live.co.uk>
Date: Wed, 23 Mar 2016 02:59:09 +0000

Hello Mitchell.

I’ve noticed that each time a character is added to a buffer, the ‘UPDATE_UI’ event is emitted up to 4 times (normally 3) with bitmask 1 (buffer.UPDATE_CONTENT). Additionally, when a character is deleted, the event is emitted twice with bitmasks 3 then 1. The following code illustrates this:

local counter, tbl = 0, {};
events.connect(events.UPDATE_UI, function(mask)
        counter, tbl[15] = (counter + 1), nil;
        table.insert(tbl, 1, string.format('[%d] = %d', counter, mask or 0));
        ui.statusbar_text = table.concat(tbl, ', ');

I wanted to let you know just in case this behaviour is not intended.

I have appended the following to my ‘~/.textadept/init.lua’ file to prevent the extra emissions:

local content_bit, previous_pos = buffer.UPDATE_CONTENT;

local content_and_sel_bits = (content_bit + buffer.UPDATE_SELECTION);

events.connect(events.UPDATE_UI, function(mask)
        if (not mask) or (mask > content_and_sel_bits) then
                return; -- changing buffers or scrolling
        local current_pos = buffer.current_pos;
        if (mask == content_bit) and (current_pos == previous_pos) then
                return false; -- prevent calls to subsequent handlers
        previous_pos = current_pos;
end, 1); -- make it the first handler to be called

Although I’ve not noticed any issues so far after adding this code, can you foresee it causing any problems under the hood?


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Received on Tue 22 Mar 2016 - 22:59:09 EDT

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