Alexander Kogtenkov: Added a note about possible optimization of BREAK_AS

2011-06-16T15:24:34Z

Added a note about possible optimization of BREAK_AS

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== Optimization ==
<e>BREAK_AS</e> can be significantly optimized if the source text is not kept inside the node, but outside it. The following approaches are possible:
# Locked source code. The source code is saved in a secure place that can be accessed whenever needed. The pair <e>position</e>-<e>count</e> can be used to get the text of the node. <e>BREAK_AS</e> has no reference fields.
# Dictionary. All character sequences are stored in a central dictionary and <e>BREAK_AS</e> keeps an index of the corresponding sequence. <e>BREAK_AS</e> for the same character sequences share the same dictionary item. Text of the node corresponds to the text of an item in the dictionary. <e>BREAK_AS</e> has no reference fields. Dictionary can be organized in a way without reference fields as well.
It's even possible to avoid creating <e>BREAK_AS</e> altogether. It's sufficient to have a '''match list'''. If there are gaps in the indexes between two adjacent leaves in the AST, it means the missing items correspond to the <e>BREAK_AS</e> elements that can be found in '''match list'''. Any information that is written in <e>BREAK_AS</e> can be computed on the fly.

Talk:Design of Roundtrip Parser - Revision history

Alexander Kogtenkov: Added a note about possible optimization of BREAK_AS