ixample returns an empty result. This turned out to be due to a power failure that left ixampl in a dubious state: it appeared to be running, but because of a file that should have been deleted but wasn't, was failing to include the results in the output. That notwithstanding, the testcase also surfaced a bug in ixampl that ought to be a separate test case for Earley parsers: If a number of alternatives all start with the same nonterminal at the same input position, only one of the alternatives actually processes the nonterminal, and then signals the other alternatives to restart if the nonterminal was successful. Because Earley treats alternatives in input-position order, normally all alternatives with the same leading nonterminal will have started by the time the nonterminal succeeds. However, if the leading nonterminal succeeds without consuming any input (i.e. it has an empty alternative), it can be the case that (some of) the other alternatives with that leading nonterminal have not yet started, and so miss the signal to restart, and thus hang for ever. I have to admit, I have long stared at that bit of code, and wondered if there was an edge case that would fail, and promised myself I would analyse it at some point. Well, this test case forced me to do it. Anyway, after changing the ixml to divert around this bug, ixampl returns 15.0 So, my suggestion would be to factor out the s's so that this test only tests Unicode, and add another test for the bug. By the way, I edited my earlier version of the Unicode version test in this way, but hadn't published it yet: Unicode: version. @version: v15; v14; v13; v12; pre-v12. -v15: Lo, Lo, Lo, Lo, +"15". -v14: Cn, Lo, Lo, Lo, +"14". -v13: Cn, Cn, Lo, Lo, +"13". -v12: Cn, Cn, Cn, Lo, +"12". -pre-v12: Cn, Cn, Cn, Cn, +"pre 12". -Lo: -[Lo], -#a. -Cn: -[Cn], -#a. Thus producing the output: <Unicode version='15'/> Steven
Received on Wednesday, 22 November 2023 12:16:13 UTC