On 13.03.2013 10:50, Simon Riggs wrote:
On 2 March 2013 18:47, Heikki Linnakangas<hlinnakan...@vmware.com> wrote:
Interestingly, the yy_transition array generated by flex used to be much
smaller:
8.3: 22072 elements
8.4: 62623 elements
master: 64535 elements
The big jump between 8.3 and 8.4 was caused by introduction of the unicode
escapes: U&'foo' [UESCAPE 'x'] . And in particular, the "error rule" for the
UESCAPE, which we use to avoid backtracking.
I experimented with a patch that uses two extra flex states to shorten the
error rules, see attached. The idea is that after lexing a unicode literal
like "U&'foo'", you enter a new state, in which you check whether an
"UESCAPE 'x'" follows. This slashes the size of the array to 36581 elements.
+1 to do this sooner rather than later
I hear no objection, so committed. (after fixing some small bugs in the
patch, and adding some comments)
- Heikki
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