Steve Lawrence created DAFFODIL-1917:
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Summary: Support for new character classes
Key: DAFFODIL-1917
URL: https://issues.apache.org/jira/browse/DAFFODIL-1917
Project: Daffodil
Issue Type: New Feature
Components: Back End, Front End, Middle "End"
Reporter: Steve Lawrence
Fix For: deferred
Daffodil v2.0 wishlist includes new character class entities LSP, LSP* and
LSP+, which are the same as WSP except they do not match line endings. This is
useful as currently it is impossible to match an empty line followed by a
newline via something like %WSP*;%NL; due to the greediness of WSP* and the
inability for our delimiter scanner to backtrack of forward lookahead.
Related, it might be useful to also add NL+ and NL* to match an unbounded
number of newlines.
Additionally, it might be a good idea to cause an SDE if a character class that
contains * or
+ is immediately followed by a character inside that character class. The
reason being that such sequences will always fail without lookahead or
backtracking, which probalby isn't worth implementing.
For security reasons, we should also implement a tunable to limit the number or
repetitions of these character entities.
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