06 07 l values

L-values are expressions that may appear on the left side of an assignment operation or as arguments corresponding to out and inout function parameters. An l-value represents a storage reference. The following expressions are legal l-values:

prefixedNonTypeName
    : nonTypeName
    | dotPrefix nonTypeName
    ;

lvalue
    : prefixedNonTypeName
    | THIS
    | lvalue "." member
    | lvalue "[" expression "]"
    | lvalue "[" expression ":" expression "]"
    | lvalue "[" expression "+" ":" expression "]"
    | "(" lvalue ")"
    ;

• Identifiers of a base or derived type.
• Structure, header, and header union field member access operations (using the dot notation).
• References to elements within header stacks (see Section Operations on header stacks): indexing, and references to last and next.
• The result of a bit-slice operator [m:l].

The following is a legal l-value: headers.stack[4].field. Note that method and function calls cannot return l-values.