What's a valid left-hand-side expression in JavaScript grammar?

Question

Okay, we all know what the valid left-hand-side expressions are. Kind of.*

But, looking at the definition from the ECMA-Script standard, I\'m very c

Answer 1

This is an alternative JavaScript grammar which only will match valid LeftHandSideExpressions, that is, LeftHandSideExpressions that are actually assignable.

NewExpression :
    PrimaryExpression
    new NewExpressionQualifier Arguments
    new NewExpressionQualifier

NewExpressionQualifier :
    NewExpressionQualifier Qualifier
    NewExpression

CallExpression :
    NewExpression
    CallExpressionQualifier Arguments

CallExpressionQualifier :
    CallExpression
    CallExpressionQualifier Qualifier

LeftHandSideExpression :
    LeftHandSideExpression Qualifier
    CallExpression Qualifier
    Identifier
    ( LeftHandSideExpression )
    ( Expression , LeftHandSideExpression )

Qualifier :
    . IdentifierName
    [ Expression ]

Each Arguments for which the choice of associated new or call expression is ambiguous shall be associated with the nearest possible new expression that would otherwise have no corresponding Arguments. I think this is one of the reasons why there is both a NewExpression and a MemberExpression nonterminal in the JavaScript grammar.