PassByConstruction

From Erights

Revision as of 13:15, 17 August 2009 (view source) Kevin Reid (Talk | contribs) (add more taxonomic info, put in specification) ← Previous diff		Revision as of 03:30, 20 April 2011 (view source) 129.241.106.22 (Talk) (nerGwbbwGJHpGA) Next diff →
Line 1:		Line 1:
-	A PassByConstruction (also 'pbc') object is one which, when sent over a [[comm system]] (e.g. [[CapTP]]) to another vat, is sent as some serialized representation, and will typically arive [[near]] rather than as a [[far reference]] back to the originating vat ([[PassByProxy]]).	+	With the bases loaded you srcutk us out with that answer!
-		+
-	{{XXX|Are there any references neither PBP nor PBC?}}	+
-		+
-	PassByConstruction objects may additionally be [[Selfless]], which by definition makes them [[PassByCopy]], i.e. exactly duplicated. On the other hand, [[Selfish]] PassByConstruction objects are used, for example, for [[una]].	+
-		+
-	==Defining pass-by-construction objects==	+
-		+
-	E [[comm system]]s serialize any object approved by the <code>pbc</code> auditor as the [[portrayal]] returned by its [[Miranda optUncall|__optUncall/0]] method. For example, this is an object which will always arrive as the number 3:	+
-		+
-	<code>	+
-	def foo implements pbc {	+
-	to [[Miranda optUncall|__optUncall]]() { return [1, "add", [2]] }	+
-	# ...	+
-	}	+
-	</code>	+
-		+
-	===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.	+
-	This code should be positioned in an [[emaker]] file in the java classpath at the location "tests/makeVector.emaker"	+
-		+
-	<pre>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(`&lt;Vector $x $y&gt;`)}	+
-	}	+
-	return vector	+
-	}	+
-	to __optUncall() :any {	+
-	return [&lt;import&gt;, "get", ["tests.makeVector"]]	+
-	}	+
-	}</pre>	+
-		+
-	Example of usage:	+
-		+
-	<pre># create a new Vector object	+
-	? def makeVector := &lt;import:tests.makeVector&gt;	+
-	# value: &lt;makeVector&gt;	+
-		+
-	? def vector := makeVector(6.6,7.7)	+
-	# value: &lt;Vector 6.6 7.7&gt;	+
-		+
-	? introducer.onTheAir()	+
-	# value: ["3DES_SDH_M2", "3DES_SDH_M"]	+
-		+
-	# function for creating a new local vat	+
-	? def seedVatAuthor := &lt;elang:interp.seedVatAuthor&gt;(&lt;unsafe&gt;).virtualize(introducer)	+
-	# value: &lt;virtualSeedVat&gt;	+
-		+
-	# Run this source code in the new vat. The method accepts a pbc object and prints it.	+
-	? def scriptSource:="def run(thing :pbc) {println(`Thing: $thing`)}"	+
-	# value: "def run(thing :near) {println(`Thing: $thing`)}"	+
-		+
-	# create the new vat. Return a far reference to the object and a reference to the vat object	+
-	? def [scriptObj, vat] := seedVatAuthor(scriptSource)	+
-	# value: [&lt;Promise&gt;, &lt;Vat newVirtualSeedVat in &lt;runs in newVirtualSeedVat&gt;&gt;]	+
-		+
-	# pass the pbc object into the new vat	+
-	? scriptObj &lt;- run(vector)	+
-	# value: &lt;Remote Promise&gt;	+
-		+
-	? Thing: &lt;Vector 6.6 7.7&gt;</pre>	+
-		+
-	{{stub}}	+
-	[[Category:ELib specification]]	+

---

Revision as of 03:30, 20 April 2011

With the bases loaded you srcutk us out with that answer!