PassByConstruction - Revision history

Kevin Reid: revert

2011-04-20T22:48:47Z

revert

New page

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]]).

{{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(`<Vector $x $y>`)}
}
return vector
}
to __optUncall() :any {
return [<import>, "get", ["tests.makeVector"]]
}
}</pre>

Example of usage:

<pre># 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>

? introducer.onTheAir()
# value: ["3DES_SDH_M2", "3DES_SDH_M"]

# function for creating a new local vat
? def seedVatAuthor := <elang:interp.seedVatAuthor>(<unsafe>).virtualize(introducer)
# value: <virtualSeedVat>

# 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: [<Promise>, <Vat newVirtualSeedVat in <runs in newVirtualSeedVat>>]

# pass the pbc object into the new vat
? scriptObj <- run(vector)
# value: <Remote Promise>

? Thing: <Vector 6.6 7.7></pre>

{{stub}}
[[Category:ELib specification]]

89.135.83.224: kKEOfZlGRkahfivNXF

2011-04-20T14:37:50Z

kKEOfZlGRkahfivNXF

←Older revision		Revision as of 14:37, 20 April 2011
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-	That's ~~way~~ the ~~betsset answer so far~~!	+	That's really thinking out of the box. Tahkns!

207.160.242.242: NoUJMpqGCdPItmtw

2011-04-20T11:28:24Z

NoUJMpqGCdPItmtw

←Older revision		Revision as of 11:28, 20 April 2011
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-	~~Kewl you suhold come up with that. Excellent~~!	+	That's way the betsset answer so far!

87.230.147.96: TLPifArKWPO

2011-04-20T08:40:32Z

TLPifArKWPO

←Older revision		Revision as of 08:40, 20 April 2011
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-	~~Wow~~! ~~Great thniikng! JK~~	+	Kewl you suhold come up with that. Excellent!

57.90.36.29: QyNpPIWQAISt

2011-04-20T08:32:38Z

QyNpPIWQAISt

←Older revision		Revision as of 08:32, 20 April 2011
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-	~~With the bases loaded you srcutk us out with that answer~~!	+	Wow! Great thniikng! JK

129.241.106.22: nerGwbbwGJHpGA

2011-04-20T03:30:19Z

nerGwbbwGJHpGA

←Older revision		Revision as of 03:30, 20 April 2011
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-	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(`<Vector $x $y>`)}~~	+
-	}	+
-	~~return vector~~	+
-	}	+
-	~~to __optUncall() :any {~~	+
-	~~return [<import>, "get", ["tests.makeVector"]]~~	+
-	}	+
-	~~}</pre>~~	+
-		+
-	~~Example of usage:~~	+
-		+
-	~~<pre># 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>~~	+
-		+
-	~~? introducer.onTheAir()~~	+
-	~~# value: ["3DES_SDH_M2", "3DES_SDH_M"]~~	+
-		+
-	~~# function for creating a new local vat~~	+
-	~~? def seedVatAuthor := <elang:interp.seedVatAuthor>(<unsafe>).virtualize(introducer)~~	+
-	~~# value: <virtualSeedVat>~~	+
-		+
-	~~# 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: [<Promise>, <Vat newVirtualSeedVat in <runs in newVirtualSeedVat>>]~~	+
-		+
-	~~# pass the pbc object into the new vat~~	+
-	~~? scriptObj <- run(vector)~~	+
-	~~# value: <Remote Promise>~~	+
-		+
-	~~? Thing: <Vector 6.6 7.7></pre>~~	+
-		+
-	~~{{stub}}~~	+
-	~~[[Category:ELib specification]]~~	+

Kevin Reid: add more taxonomic info, put in specification

2009-08-17T13:15:08Z

add more taxonomic info, put in specification

←Older revision		Revision as of 13:15, 17 August 2009
Line 1:		Line 1:
-	~~When objects are transfered to another~~ [[~~vat~~]], ~~they arrive~~ as [[~~far reference\|far references~~]] ~~by default. To reconstruct the object~~ as a [[~~near~~ reference]] in the ~~receiving~~ vat~~, Pass By Construction~~ (~~pbc~~) ~~can~~ be used.	+	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]]).
		+
		+	{{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:		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:
Line 10:		Line 16:
	</code>		</code>

-	==Example==	+	===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 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.
Line 59:		Line 65:

	? Thing: <Vector 6.6 7.7></pre>		? Thing: <Vector 6.6 7.7></pre>
		+
		+	{{stub}}
		+	[[Category:ELib specification]]

Kevin Reid: Pass By Construction moved to PassByConstruction: use formal name

2009-08-17T13:09:33Z

Pass By Construction moved to PassByConstruction: use formal name

←Older revision

Revision as of 13:09, 17 August 2009

Mscheffler: linked to emaker article

2007-04-23T08:20:30Z

linked to emaker article

←Older revision		Revision as of 08:20, 23 April 2007
Line 13:		Line 13:

	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 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 a file in the java classpath at the location "tests/makeVector.emaker"	+	This code should be positioned in an [[emaker]] file in the java classpath at the location "tests/makeVector.emaker"

	<pre>def makeVector implements pbc {		<pre>def makeVector implements pbc {

Kevin Reid: removing description of portrayals now that they have a separate page

2007-04-21T14:07:29Z

removing description of portrayals now that they have a separate page

←Older revision		Revision as of 14:07, 21 April 2007
Line 1:		Line 1:
	When objects are transfered to another [[vat]], they arrive as [[far reference\|far references]] by default. To reconstruct the object as a [[near reference]] in the receiving vat, Pass By Construction (pbc) can be used.		When objects are transfered to another [[vat]], they arrive as [[far reference\|far references]] by default. To reconstruct the object as a [[near reference]] in the receiving vat, Pass By Construction (pbc) can be used.

-	~~To mark an~~ object ~~as pbc, it has to be~~ approved by the <code>pbc</code> auditor:	+	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>		<code>
Line 9:		Line 9:
	}		}
	</code>		</code>
-
-	__optUncall is a [[miranda message]]. When the object is sent out of the [[current vat]], __optUncall/0 is called by the [[comm system]], and the result of the call is used as the structure to represent the object to the destination [[vat]].
-
-	~~The triple returned by __optUncall, a '''portrayal''', has this format:~~
-	~~<pre>~~
-	~~[<var>recipient</var> :[[near]], <var>verb</var> :[[String]], <var>args</var> :[[List]]]~~
-	~~</pre>~~
-	~~which together specify a call to perform in the receiving vat; the object is unserialized as the result of this call.~~

	==Example==		==Example==