ShockScript: Patterns

Matching patterns may be used in a number of contexts, including variable bindings, try..catch clauses, switch type cases, if..let and assignment left-hand sides.

Where applicable, expressions are disambiguated into those patterns, in which case any incompatible or illegal expression results in a syntax error; for example, an expression is disambiguated into a pattern inside an assignment whose left-hand side is either an array or object literal.

Syntax

Pattern :
[lookahead ≠ undefined if pattern is nested] IdentifierPattern
ArrayPattern
ObjectPattern
ConstantPattern [if pattern is nested]
Pattern NonNull

TypedPattern :
Pattern [lookahead ≠ :]
Pattern : TypeExpression