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- | ===== What is AmbientTalk? | ||
- | {{: | ||
- | |||
- | For the programming language adepts: AmbientTalk is: | ||
- | * **dynamically typed**, which is **not** the same as being untyped: AmbientTalk //values// are typed, but // | ||
- | * object-oriented, | ||
- | * event-driven: | ||
- | * distributed: | ||
- | * **symbiotic**: | ||
- | |||
- | A word of warning, though: AmbientTalk is **not** a stable development platform. Rather, it is a research artifact used as a " | ||
- | |||
- | ==== AmbientTalk in a nutshell ==== | ||
- | |||
- | Enough talking, let's delve into some AmbientTalk code by means of a simple example to see whether we can spark your interest in AmbientTalk. The demo program we're about to explore is an extremely simple instant messenger program. Each instant messenger runs on e.g. a PDA, laptop or cell phone. When peers join the ad hoc network, the instant messenger should issue a warning to the user that a new buddy is available for chatting. The user can then send simple text messages to that buddy. When peers leave the ad hoc network, the user should also be notified. Off we go. | ||
- | |||
- | === Design === | ||
- | |||
- | Here is the skeleton code for the instant messenger: | ||
- | |||
- | < | ||
- | def createInstantMessenger(username) { | ||
- | defstripe InstantMessenger; | ||
- | |||
- | def TextMessage := isolate: { ... }; | ||
- | def buddyList := jlobby.java.util.HashMap.new(); | ||
- | def printMessage(textMessage) { ... }; | ||
- | |||
- | def localInterface := object: { | ||
- | def sendTextMessage(to, | ||
- | }; | ||
- | def remoteInterface := object: { | ||
- | def receiveTextMessage(textMessage, | ||
- | def getName(future) { ... }; | ||
- | }; | ||
- | | ||
- | export: remoteInterface as: InstantMessenger; | ||
- | whenever: InstantMessenger discovered: { |messenger| | ||
- | ... | ||
- | }; | ||
- | localInterface; | ||
- | }; | ||
- | </ | ||
- | |||
- | An instant messenger object is created by invoking a function called '' | ||
- | |||
- | === Implementation === | ||
- | |||
- | < | ||
- | def createInstantMessenger(username) { | ||
- | |||
- | defstripe InstantMessenger; | ||
- | |||
- | def TextMessage := isolate: { | ||
- | def from := nil; | ||
- | def content := nil; | ||
- | def init(f,c) { | ||
- | from := f; | ||
- | content := c; | ||
- | }; | ||
- | }; | ||
- | |||
- | def buddyList := jlobby.java.util.HashMap.new(); | ||
- | | ||
- | def printMessage(textMessage) { | ||
- | system.println(textMessage.from + ": " + | ||
- | textMessage.content) | ||
- | }; | ||
- | |||
- | def localInterface := object: { | ||
- | def sendTextMessage(to, | ||
- | def buddy := buddyList.get(to); | ||
- | if: (nil == buddy) then: { | ||
- | system.println(" | ||
- | } else: { | ||
- | def msg := TextMessage.new(username, | ||
- | buddy< | ||
- | def resolve() { | ||
- | printMessage(msg); | ||
- | } | ||
- | }); | ||
- | }; | ||
- | }; | ||
- | }; | ||
- | |||
- | def remoteInterface := object: { | ||
- | def receiveTextMessage(textMessage, | ||
- | printMessage(textMessage); | ||
- | future< | ||
- | }; | ||
- | def getName(future) { future< | ||
- | }; | ||
- | | ||
- | export: remoteInterface as: InstantMessenger; | ||
- | | ||
- | whenever: InstantMessenger discovered: { |messenger| | ||
- | messenger< | ||
- | def resolve(name) { | ||
- | if: (nil == buddyList.get(name)) then: { | ||
- | buddyList.put(name, | ||
- | system.println(" | ||
- | when: messenger disconnected: | ||
- | system.println(" | ||
- | }; | ||
- | when: messenger reconnected: | ||
- | system.println(" | ||
- | }; | ||
- | }; | ||
- | }; | ||
- | }); | ||
- | }; | ||
- | |||
- | localInterface; | ||
- | }; | ||
- | </ |