Constructs a new Symbol representing the provided name.
The name must be a valid public Dart member name, public constructor name, or library name, optionally qualified.
A qualified name is a valid name preceded by a public identifier name
and a '.
', e.g., foo.bar.baz=
is a qualified version of baz=
.
That means that the content of the name
String must be either
_
"),+
", "-
", "*
", "/
", "%
", "~/
", "&
", "|
",
"^
", "~
", "<<
", ">>
", "<
", "<=
", ">
", ">=
", "==
",
"[]
", "[]=
", or "unary-
"),.
',Symbol instances created from the same name
are equal,
but not necessarily identical, but symbols created as compile-time
constants are canonicalized, as all other constant object creations.
assert(new Symbol("foo") == new Symbol("foo"));
assert(identical(const Symbol("foo"), const Symbol("foo")));
If name
is a single identifier that does not start with an underscore,
or it is a qualified identifier,
or it is an operator name different from unary-
,
then the result of const Symbol(name)
is the same instance that
the symbol literal created by prefixing #
to the content of name
would evaluate to.
assert(new Symbol("foo") == #foo);
assert(new Symbol("[]=") == #[]=]);
assert(new Symbol("foo.bar") == #foo.bar);
assert(identical(const Symbol("foo"), #foo));
assert(identical(const Symbol("[]="), #[]=]));
assert(identical(const Symbol("foo.bar"), #foo.bar));
This constructor cannot create a Symbol instance that is equal to
a private symbol literal like #_foo
.
const Symbol("_foo") // Invalid
``
The created instance overrides [Object.==].
The following text is non-normative:
Creating non-const Symbol instances may result in larger output. If
possible, use `MirrorsUsed` from "dart:mirrors" to specify which names
might be passed to this constructor.
const factory Symbol(String name) = internal.Symbol;