std.d.lexer requirements

[Walter Bright]

On 8/2/2012 1:41 PM, Jacob Carlborg wrote:
> On 2012-08-02 21:35, Walter Bright wrote:
>
>> A good IDE should do its parsing in a separate thread, so the main user
>> input thread remains crisp and responsive.
>>
>> If the user edits the text while the parsing is in progress, the
>> background parsing thread simply abandons the current parse and starts
>> over.
>
> It still needs to update the editor view with the correct syntax highlighting
> which needs to be done in the same thread as the rest of the GUI.
>

The rendering code should be in yet a third thread.

An editor I wrote years ago had the rendering code in a separate thread from 
user input. You never had to wait to type in commands, the rendering would catch 
up when it could. What was also effective was the rendering would abandon a 
render midstream and restart it if it detected that the underlying data had 
changed in the meantime. This meant that the display was never more than one 
render out of date.

Although the code itself wasn't any faster, it certainly *felt* faster with this 
approach. It made for crisp editing even on a pig slow machine.