[colm-users] new way of constructing trees

Adrian Thurston thurston at complang.org
Wed Sep 9 23:54:42 UTC 2009


I'm experimenting with a new way in Colm to make trees. The existing 
construct expression is useful for building trees in a bottom up 
fashion. It is parsed at compile-time to give some static assurance of 

The existing parse expression can be used to parse from a stream source, 
or reparse the text of a tree as a new type. The parsing happens at 
run-time and may fail.

A new third method, the accumulator, can be used to incrementally build 
a tree by parsing little bits at a time. This is useful for building an 
output tree over the course of a top-down, left-right traversal.

See here for a simple example:



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