PassByConstruction
From Erights
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</code> | </code> | ||
will be passed-by-construction across CapTP. This means that its __optUncall() method will be called on the sending side, the elements of the result triple will be passed, and the corresponding triple as received will be called (here, as “E.call(1, "add", [2])”) to create the object as received. | will be passed-by-construction across CapTP. This means that its __optUncall() method will be called on the sending side, the elements of the result triple will be passed, and the corresponding triple as received will be called (here, as “E.call(1, "add", [2])”) to create the object as received. | ||
| + | |||
| + | ==Example== | ||
| + | |||
| + | The first part of the example is a maker for a 2D Vector. The created vectors are Pass By Construction, they should pass the guard :pbc. | ||
| + | The method __optUncall is a [Miranda_Method miranda method]. When the vector is copied to another [vat], the method __optUncall is called by the CapTP networking subsystem of E. The result of the method is used to recreate the object in the destination [vat]. | ||
| + | This code should be positioned in a file in the java classpath at the location "tests.makeVector.emaker" | ||
| + | |||
| + | <code> | ||
| + | def makeVector implements pbc { | ||
| + | to run(var x, var y) { | ||
| + | def vector implements pbc { | ||
| + | to getX() :any { return x } | ||
| + | to getY() :any { return y } | ||
| + | to __optUncall() :any { return [makeVector, "run", [x,y]] } | ||
| + | to __printOn(out) {out.print(`<Vector $x $y>`)} | ||
| + | } | ||
| + | return vector | ||
| + | } | ||
| + | to __optUncall() :any { | ||
| + | return [<import>, "get", ["tests.makeVector"]] | ||
| + | } | ||
| + | } | ||
| + | </code> | ||
| + | |||
| + | Example of usage: | ||
| + | <code> | ||
| + | #create a new Vector object | ||
| + | ? def makeVector := <import:tests.makeVector> | ||
| + | # value: <makeVector> | ||
| + | |||
| + | ? def vector := makeVector(6.6,7.7) | ||
| + | # value: <Vector 6.6 7.7> | ||
| + | |||
| + | #create a new vat | ||
| + | ? introducer.onTheAir() | ||
| + | # value: ["3DES_SDH_M2", "3DES_SDH_M"] | ||
| + | |||
| + | ? def seedVatAuthor := <elang:interp.seedVatAuthor>(<unsafe>).virtualize((introducer)) | ||
| + | # value: <virtualSeedVat> | ||
| + | |||
| + | # source code for the new vat | ||
| + | ? def scriptSource:="def run(thing :pbc) {println(`Thing: $thing`)}" | ||
| + | # value: "def run(thing :near) {println(`Thing: $thing`)}" | ||
| + | |||
| + | ? def [scriptObj, vat] := seedVatAuthor(scriptSource) | ||
| + | # value: [<Promise>, <Vat newVirtualSeedVat in <runs in newVirtualSeedVat>>] | ||
| + | |||
| + | ? scriptObj <- run(vector) | ||
| + | # value: <Remote Promise> | ||
| + | |||
| + | ? Thing: <Vector 6.6 7.7> | ||
| + | </code> | ||
Revision as of 09:58, 18 April 2007
An object declared as, for example
def foo implements pbc {
to __optUncall() { return [1, "add", [2]] }
# ...
}
will be passed-by-construction across CapTP. This means that its __optUncall() method will be called on the sending side, the elements of the result triple will be passed, and the corresponding triple as received will be called (here, as “E.call(1, "add", [2])”) to create the object as received.
Example
The first part of the example is a maker for a 2D Vector. The created vectors are Pass By Construction, they should pass the guard :pbc. The method __optUncall is a [Miranda_Method miranda method]. When the vector is copied to another [vat], the method __optUncall is called by the CapTP networking subsystem of E. The result of the method is used to recreate the object in the destination [vat]. This code should be positioned in a file in the java classpath at the location "tests.makeVector.emaker"
def makeVector implements pbc {
to run(var x, var y) {
def vector implements pbc {
to getX() :any { return x }
to getY() :any { return y }
to __optUncall() :any { return [makeVector, "run", [x,y]] }
to __printOn(out) {out.print(`<Vector $x $y>`)}
}
return vector
}
to __optUncall() :any {
return [<import>, "get", ["tests.makeVector"]]
}
}
Example of usage:
- create a new Vector object
? def makeVector := <import:tests.makeVector>
- value: <makeVector>
? def vector := makeVector(6.6,7.7)
- value: <Vector 6.6 7.7>
- create a new vat
? introducer.onTheAir()
- value: ["3DES_SDH_M2", "3DES_SDH_M"]
? def seedVatAuthor := <elang:interp.seedVatAuthor>(<unsafe>).virtualize((introducer))
- value: <virtualSeedVat>
- source code for the new vat
? def scriptSource:="def run(thing :pbc) {println(`Thing: $thing`)}"
- value: "def run(thing :near) {println(`Thing: $thing`)}"
? def [scriptObj, vat] := seedVatAuthor(scriptSource)
- value: [<Promise>, <Vat newVirtualSeedVat in <runs in newVirtualSeedVat>>]
? scriptObj <- run(vector)
- value: <Remote Promise>
? Thing: <Vector 6.6 7.7>
