Drop do while #6994
Drop do while #6994
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We used three different methods, which all did the same thing in the end.
Drop . Rewrite to instead. This can be done by the compiler under -rewrite.
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It seems odd, initially, not to have the statement and predicate wrapped in I checked to see if the predicate in an This would help to establish an invariant that new identifiers introduced in expressions comprising of multiple keywords would be scoped to the entire expression. However, would this work? There's an argument to be made (though I'm not sure I have strong opinions) that a block which evaluates to a Another quirk of the new syntax is that a multi-line predicate can be written without braces, whereas a multi-line action cannot, though it seems like the latter would be by far the more common case. |
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@propensive The brace-less syntax in |
Ok, great. I'll wait and see. :) |
Co-Authored-By: Nicolas Stucki <[email protected]>
| atSpan(in.skipToken()) { | ||
| in.errorOrMigrationWarning( | ||
| i"""`do <body> while <cond>' is no longer supported, | ||
| |use `while {<body> ; <cond>} do ()' instead. |
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I'm pretty sure we discussed today that this PR shouldn't be mixed up with that possible future syntax. Hence I believe we should suggest while ({ body; cond }) () here instead.
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| patch(source, cond.span.endPos, "}) ()") | ||
| } | ||
| WhileDo(Block(body :: Nil, cond), Literal(Constant(()))) |
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This is incorrect, as both body and block could define symbols with the same name. If they are put together in a single Block, the scopes will clash.
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We will need a test for this.
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Actually, body and cond are already blocks if they have definitions. I added some tests in #7002. Did I miss some other definitions that could be represented differently?
Drop
in favor of
Under -rewrite one syntax can be rewritten to the other.
Reasons:
while. So there seems to be little point in having it as a separate syntax construct.doas a statement continuation token.whileas the only loop syntax gives an elegant solution to the "loop-and-a-half" problem. E.g.