TC39 General
2024-08-07
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01:05
<ljharb>
as i commented there, i think import.meta only makes sense for things that are specific to the ES module it’s used in, and env vars are globals
01:42
<Meghan Denny>
have there been proposals in the past for a seedable prng?
01:54
<kriskowal>
have there been proposals in the past for a seedable prng?
I like to think of all such proposals as new Math. But, in earnest there is TabAtkins‘s https://github.com/tc39/proposal-seeded-random
01:59
<Meghan Denny>
thanks!
16:05
<nicolo-ribaudo>

For anybody good at grammar -- is this reading of the spec correct? https://github.com/tc39/test262/pull/4189

Or is it invalid syntax because once we enter the MethodDefinition (which we can enter, because get is a valid first token for it) we don't backtrack?

16:16
<Michael Ficarra>
the test looks correct to me
16:17
<nicolo-ribaudo>
Ok thanks!
16:19
<Michael Ficarra>
grammar alternatives in 262 are not ordered as they are in PEGs
16:21
<nicolo-ribaudo>

And here there is no ASI right? Because the offending token is x and not async:

class B {
    get
    async x() {}
}
19:39
<Michael Ficarra>
correct, the offending token is x and it's not separate by a LineTerminator from async, so ASI does not occur and this fails to parse
20:08
<littledan>
grammar alternatives in 262 are not ordered as they are in PEGs
except for Annex B regexps right?
20:09
<littledan>
or did that change?
20:10
<littledan>

B.1.2 Regular Expressions Patterns
The syntax of 22.2.1 is modified and extended as follows. These changes introduce ambiguities that are broken by the ordering of grammar productions and by contextual information. When parsing using the following grammar, each alternative is considered only if previous production alternatives do not match.

20:10
<Michael Ficarra>
possibly, I don't often consider the RegExp grammar
20:10
<Michael Ficarra>
gross
20:10
<littledan>
(I'm not sure if thumbs-up is an appropriate emoji response here)
20:11
<Michael Ficarra>
I'm going to go back to not thinking much about Annex B
20:22
<shu>
B for Best
20:22
<shu>
or maybe B for ✨️B✨️eautiful
20:25
<bakkot>
https://github.com/tc39/ecma262/pull/2445 should eliminate the ordering, if we ever get it
20:44
<jmdyck>
Note that all of 2445's changes to the grammar are ready for review. I think the only reason the PR is still in draft is that it needs to generalize the definition of lookahead-constraints somewhat.
20:48
<jmdyck>
But there didn't seem to be much interest.