do
expressions are a syntactic construct which allows putting (some) statements in expression position without needing an immediately-invoked function expression.
With parameters labelSet and isLast.
With parameter labelSet.
Here "empty" means "consisting solely of
labelSet is always empty when this SDO is invoked by other operations. It is used to track internally the labels which, if broken, would cause the statements being examined to be empty, as in label: { break label; }
.
With parameter labelSet.
This SDO answers the question "is the first non-empty statement in this
TODO: now that we allow break/continue in do expressions, this needs to be updated to check every expression position in every statement to see if it has a
Note the additional lookahead for do
in ExpressionStatements. This prevents using do
expressions in statement position, where they are ambiguous with do
statements.
TODO: thread the Return grammar parameter through the entire expression grammar. It is allowed in parameter lists and arrow expression bodies, but not class bodies. In other circumstances it's inherited from the containing statement.
TODO: thread ContainsUndefinedBreakTarget and ContainsUndefinedContinueTarget through the entire expression grammar.
TODO: thread VarDeclaredNames through the entire expression grammar and update existing uses (
TODO: thread ContainsDuplicateLabels through the entire expression grammar.
TODO: ban do-exprs which are inside of formal parameter lists and which Contain a
Maybe it is worth abstracting out a single "CollectDoExpressionsFromExpression" SDO that other things can be written in terms of.
© 2021 Dave Herman, Chris Krychom, Kevin Gibbons
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