Mike Beckerle created DAFFODIL-3048:
---------------------------------------
Summary: Generalized peek-ahead feature in DFDL
Key: DAFFODIL-3048
URL: https://issues.apache.org/jira/browse/DAFFODIL-3048
Project: Daffodil
Issue Type: New Feature
Components: Back End, Front End
Affects Versions: 4.0.0
Reporter: Mike Beckerle
Daffodil should implement the generalized look-ahead/peek-ahead feature
described here:
[https://github.com/OpenGridForum/DFDL/issues/75]
This is pretty easy to implement. It's a degenerate form of backtracking where
only the position of the parser is backtracked. The other things, infoset,
variable-settings, etc are all retained.
This is an alternative mechanism enabling use of choice-by-dispatch without
schema authors having to contort the record layouts by hoisting out the fields
that are dispatched on.
The optimization described in DAFFODIL-2831 only works if the various record
types in a choice are distinguished by an initiator.
This generalized look/peek ahead capability would enable choice-by-dispatch on
field values that are not necessarily in tthe first position of each record,
but which are still used uniformly for every record type.
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
