import ceylon.language.meta.model {
Value,
Attribute,
AppliedType = Type,
IncompatibleTypeException,
StorageException
}
"""A value declaration.
<a name="toplevel-sample">a>
### Usage sample for toplevel value
Getting a model requires applying type arguments to the
value declaration with [[apply]] in order to be able to read that value. For example, here is how you would
obtain a value model that you can read from a toplevel attribute declaration:
String foo = "Hello";
void test(){
// We need to apply the the foo declaration in order to get the foo value model
Value<String> valueModel = `value foo`.apply<String>();
// This will print: Hello
print(valueModel.get());
}
<a name="member-sample">a>
### Usage sample for attributes
For attributes it is a bit longer, because attributes need to be applied the containing type, so you should
use [[memberApply]] and start by giving the containing closed type:
class Outer(){
shared String foo => "Hello";
}
void test(){
// Apply the containing closed type `Outer` to the attribute declaration `Outer.foo`
Attribute<Outer,String> valueModel = `value Outer.foo`.memberApply<Outer,String>(`Outer`);
// We now have an Attribute, which needs to be applied to a containing instance in order to become a
// readable value:
Value<String> boundValueModel = valueModel(Outer());
// This will print: Hello
print(boundValueModel.get());
}
"""
shared sealed interface ValueDeclaration
satisfies FunctionOrValueDeclaration & GettableDeclaration {
"True if this declaration is annotated with [[late|ceylon.language::late]]."
since("1.2.0")
shared formal Boolean late;
"True if this declaration is annotated with [[variable|ceylon.language::variable]]."
shared formal Boolean variable;
"True if this declaration is an `object` declaration, whose type is an anonymous class."
since("1.1.0")
shared formal Boolean objectValue;
"This value's anonymous class declaration if this value is an object declaration. `null` otherwise."
since("1.1.0")
shared formal ClassDeclaration? objectClass;
"Applies this value declaration in order to obtain a value model.
See [this code sample](#toplevel-sample) for an example on how to use this."
throws(`class IncompatibleTypeException`, "If the specified `Get` or `Set` type arguments are not compatible with the actual result.")
shared formal Value<Get, Set> apply<Get=Anything, Set=Nothing>();
"Applies this `static` value declaration in order to obtain a value model."
throws(`class IncompatibleTypeException`, "If the specified `Get` or `Set` type arguments are not compatible with the actual result.")
shared formal Value<Get, Set> staticApply<Get=Anything, Set=Nothing>(AppliedType<Object> containerType);
"Applies the given closed container type to this attribute declaration in order to obtain an attribute model.
See [this code sample](#member-sample) for an example on how to use this."
throws(`class IncompatibleTypeException`, "If the specified `Container`, `Get` or `Set` type arguments are not compatible with the actual result.")
shared formal Attribute<Container, Get, Set> memberApply<Container=Nothing, Get=Anything, Set=Nothing>(AppliedType<Object> containerType);
"Reads the current value of this toplevel value."
shared actual default Anything get()
=> apply<Anything, Nothing>().get();
"Reads the current value of this attribute on the given container instance."
throws(`class IncompatibleTypeException`, "If the specified container is not compatible with this attribute.")
throws(`class StorageException`,
"If this attribute is not stored at runtime, for example if it is neither shared nor captured.")
shared actual default Anything memberGet(Object container)
=> memberApply<Nothing, Anything, Nothing>(`Nothing`).bind(container).get();
"Reads the current value of this `static` attribute."
throws(`class IncompatibleTypeException`, "If the specified `Get` or `Set` type arguments are not compatible with the actual result.")
shared actual default Anything staticGet(AppliedType<Object> containerType)
=> staticApply<Anything, Nothing>(containerType).get();
"Sets the current value of this toplevel value."
shared default void set(Anything newValue)
=> apply<Anything,Nothing>().setIfAssignable(newValue);
"Sets the current value of this attribute on the given container instance."
throws(`class IncompatibleTypeException`, "If the specified container or new value type is not compatible with this attribute.")
throws(`class StorageException`,
"If this attribute is not stored at runtime, for example if it is neither shared nor captured.")
shared formal void memberSet(Object container, Anything newValue);
//=> memberApply<Nothing, Anything, Nothing>(`Nothing`).bind(container).setIfAssignable(newValue);
"Returns the setter declaration for this variable if there is one, `null` otherwise."
shared formal SetterDeclaration? setter;
}