flex: How can I make REJECT cascade across start condition boundaries?
How can I make REJECT cascade across start condition boundaries?
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You can do this as follows. Suppose you have a start condition 'A', and
after exhausting all of the possible matches in '<A>', you want to try
matches in '<INITIAL>'. Then you could use the following:
%x A
%%
<A>rule_that_is_long ...; REJECT;
<A>rule ...; REJECT; /* shorter rule */
<A>etc.
...
<A>.|\n {
/* Shortest and last rule in <A>, so
* cascaded REJECTs will eventually
* wind up matching this rule. We want
* to now switch to the initial state
* and try matching from there instead.
*/
yyless(0); /* put back matched text */
BEGIN(INITIAL);
}
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