Method `->=()

Method `->=

mixed `->=(object arg, string index, mixed val)
mixed `->=(mapping arg, string index, mixed val)
bool `->=(multiset arg, string index, bool val)

Description

Arrow index assignment.

Every lvalue expression with the -> operator becomes a call to this function, i.e. a->b=c is the same as predef::`->=(a,"b",c) where "b" is the symbol b in string form.

This function behaves like `[]=, except that the index is passed literally as a string instead of being evaluated.

If arg is an object that implements lfun::`->=(), that function will be called with index and val as the arguments.

arg can have any of the following types:

object	The non-protected (ie public) variable named index will be looked up in arg, and assigned val.
array|mapping	Index index in arg will be assigned val.
multiset	If val is 0 (zero), one occurrance of index in arg will be removed. Otherwise index will be added to arg if it is not already there.

Returns

val will be returned.

Note

In an expression a->b=c, the symbol b can be any token that matches the identifier syntax - keywords are disregarded in that context.

Note

An arrow indexing expression in a non-lvalue context, i.e. where the index is being queried instead of assigned, uses `-> instead of this function.

See also

`[]=(), lfun::`->=(), `->