openmethods

1 
2 import openmethods; // import lib
3 mixin(registerMethods); // once per module - don't forget!
4 
5 interface  Animal {}
6 class Dog : Animal {}
7 class Pitbull : Dog {}
8 class Cat : Animal {}
9 class Dolphin : Animal {}
10 
11 // open method with single argument <=> virtual function "from outside"
12 string kick(virtual!Animal);
13 
14 @method // implement 'kick' for dogs
15 string _kick(Dog x) // note the underscore
16 {
17   return "bark";
18 }
19 
20 @method("kick") // use a different name for specialization
21 string notGoodIdea(Pitbull x)
22 {
23   return next!kick(x) ~ " and bite"; // aka call 'super'
24 }
25 
26 // multi-method
27 string meet(virtual!Animal, virtual!Animal);
28 
29 // 'meet' implementations
30 @method
31 string _meet(Animal, Animal)
32 {
33   return "ignore";
34 }
35 
36 @method
37 string _meet(Dog, Dog)
38 {
39   return "wag tail";
40 }
41 
42 @method
43 string _meet(Dog, Cat)
44 {
45   return "chase";
46 }
47 
48 void main()
49 {
50   updateMethods(); // once per process - don't forget!
51 
52   import std.stdio;
53 
54   Animal rex = new Pitbull, snoopy = new Dog;
55   writeln("kick snoopy: ", kick(snoopy)); // bark
56   writeln("kick rex: ", kick(rex)); // bark and bite
57 
58   Animal felix = new Cat, flipper = new Dolphin;
59   writeln("rex meets felix: ", meet(rex, felix)); // chase
60   writeln("rex meets snoopy: ", meet(rex, snoopy)); // wag tail
61   writeln("rex meets flipper: ", meet(rex, flipper)); // ignore
62 }

Members

Aliases

MethodErrorHandler

alias MethodErrorHandler = void function(MethodError error)

Undocumented in source.

VirtualType

alias VirtualType(T : virtual!U, U) = U

Undocumented in source.

Classes

MethodError

class MethodError

Information passed to the error handler function.

virtual

class virtual(T)

Mark a parameter as virtual, and declare a method.

Enums

IsVirtual

eponymoustemplate IsVirtual(T)

Undocumented in source.

IsVirtual

eponymoustemplate IsVirtual(T : virtual!U, U)

Undocumented in source.

Functions

TypeIds

auto TypeIds()

Undocumented in source. Be warned that the author may not have intended to support it.

_registerMethods

string _registerMethods()

Undocumented in source. Be warned that the author may not have intended to support it.

defaultMethodErrorHandler

void defaultMethodErrorHandler(MethodError error)

Undocumented in source. Be warned that the author may not have intended to support it.

needUpdateMethods

bool needUpdateMethods()

Undocumented in source. Be warned that the author may not have intended to support it.

next

auto next(T args)

Call the next most specialized override if it exists. In other words, call the override that would have been called if this one had not been defined.

registerMethods

string registerMethods(string moduleName)

Used as a string mixin: register the methods declaration and definitions in the current module.

setMethodErrorHandler

void function(MethodError error) setMethodErrorHandler(void function(MethodError error) handler)

Set the function that is called if a method cannot be called with the arguments. Default is to abort the program.

updateMethods

void updateMethods()

Update the runtime dispatch tables. Must be called once before calling any method. Typically this is done at the beginning of main.

Mixin templates

Restrict

mixintemplate Restrict(M...)

Undocumented in source.

_method

mixintemplate _method(string name, R, A...)

Undocumented in source.

_registerSpecs

mixintemplate _registerSpecs(alias MODULE)

Undocumented in source.

implement

mixintemplate implement(alias M, alias S)

Undocumented in source.

Structs

Method

struct Method(string id, string Mptr, R, T...)

Undocumented in source.

MethodTag

struct MethodTag

Undocumented in source.

Restriction

struct Restriction

Undocumented in source.

Runtime

struct Runtime

Undocumented in source.

method

struct method

Used as an attribute: add an override to a method.

mptr

struct mptr

Undocumented in source.

Templates

CallParams

template CallParams(T...)

Undocumented in source.

VirtualArity

template VirtualArity(QP...)

Undocumented in source.

castArgs

template castArgs(T...)

Undocumented in source.

Variables

errorHandler

MethodErrorHandler errorHandler;

Undocumented in source.

hasVirtualParameters

bool hasVirtualParameters(alias F);

Undocumented in source.

• nextdemo
• openmethods