Language Reference/Terms/Anonymous Predicates - Revision history

Thomas Linder Puls: Review

2025-08-22T11:05:54Z

Review

Tbn: /* Background threads */ minor typos

2016-11-08T09:14:37Z

Background threads: minor typos

← Older revision		Revision as of 11:14, 8 November 2016
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	===== Background threads =====		===== Background threads =====

	The routine for starting a thread takes a null-ary predicate and ~~run~~ it in the new thread. But you nearly always need to pass some input data to the job in the new thread.		The routine for starting a thread takes a null-ary predicate and runs it in the new thread. But you nearly always need to pass some input data to the job in the new thread.
	This is possible in several ways, but the absolutely simplest way is to use anonymous predicates.		This is possible in several ways, but the absolutely simplest way is to use anonymous predicates.
	The project <vp>bgDemo</vp> from the Visual Prolog example collection (that can be installed from the IDE) use this method.		The project <vp>bgDemo</vp> from the Visual Prolog example collection (that can be installed from the IDE) use this method.
	The project has a form that can start background job and display status information from the job in a <vp>jobControl</vp> that is added to the form.		The project has a form that can start a background job and display status information from the job in a <vp>jobControl</vp> that is added to the form.
	A background job is a predicate that will receive a <vp>jobLog</vp>, which it can use to report status and completion degree:		A background job is a predicate that will receive a <vp>jobLog</vp>, which it can use to report status and completion degree:

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	jobCtrl:postAction(Action).</vip>		jobCtrl:postAction(Action).</vip>

	<vp>Action</vp> is a null-ary predicate that will set the status in the <vp>jobCtrl</vp>. We post this action to the <vp>jobCtrl</vp>. When the <vp>jobCtrl</vp> receives the action it invokes it and is thus updated. This way ~~that~~ actual update of the control will be performed by the GUI thread.		<vp>Action</vp> is a null-ary predicate that will set the status in the <vp>jobCtrl</vp>. We post this action to the <vp>jobCtrl</vp>. When the <vp>jobCtrl</vp> receives the action it invokes it and is thus updated. This way, the actual update of the control will be performed by the GUI thread.
	This anonymous predicate not only captures the <vp>Status</vp> variable it also captures the <vp>jobCtrl</vp> fact.		This anonymous predicate not only captures the <vp>Status</vp> variable it also captures the <vp>jobCtrl</vp> fact.

SergeMukhin: remove filterPredicate

2015-01-01T22:04:52Z

remove filterPredicate

← Older revision		Revision as of 00:04, 2 January 2015
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	<vip>class predicates		<vip>class predicates
	writeFiltered :		writeFiltered :
	(string L, ~~filterPredicate~~{integer} Filter).		(string L, predicate_dt{integer} Filter).
	clauses		clauses
	writeFiltered(Label, Filter) :-		writeFiltered(Label, Filter) :-
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	<source lang="text">> 3 [4,5,6,7,8,9]		<source lang="text">> 3 [4,5,6,7,8,9]
	Rem3 [3,6,9]</source>		Rem3 [3,6,9]</source>


	===== Sorting =====		===== Sorting =====

Thomas Linder Puls: subarticle

2013-02-12T09:36:16Z

subarticle

← Older revision		Revision as of 11:36, 12 February 2013
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	We have used an anonymous predicate to perform the execution of the rest of the script. This anonymous predicate captures <vp>T</vp> and <vp>OnDone</vp>.		We have used an anonymous predicate to perform the execution of the rest of the script. This anonymous predicate captures <vp>T</vp> and <vp>OnDone</vp>.
	<noinclude>~~[[Category:Language Reference Subarticle]]~~</noinclude>		<noinclude>{{LanguageReferenceSubarticle\|Terms/Anonymous Predicates}}</noinclude>

Thomas Linder Puls: line

2012-10-25T15:46:15Z

line

← Older revision		Revision as of 17:46, 25 October 2012
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	We have used an anonymous predicate to perform the execution of the rest of the script. This anonymous predicate captures <vp>T</vp> and <vp>OnDone</vp>.		We have used an anonymous predicate to perform the execution of the rest of the script. This anonymous predicate captures <vp>T</vp> and <vp>OnDone</vp>.

	<noinclude>[[Category:Language Reference Subarticle]]</noinclude>		<noinclude>[[Category:Language Reference Subarticle]]</noinclude>

Thomas Linder Puls: ...

2009-05-05T12:00:07Z

...

← Older revision		Revision as of 14:00, 5 May 2009
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	===== Capturing ellipsis (…) =====		===== Capturing ellipsis (...) =====

	An anonymous predicate can capture the ellipsis variable (i.e. …):		An anonymous predicate can capture the ellipsis variable (i.e. ...):

	<vip>clauses		<vip>clauses

Thomas Linder Puls: Categorized

2008-10-29T19:59:41Z

Categorized

← Older revision		Revision as of 21:59, 29 October 2008
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	We have used an anonymous predicate to perform the execution of the rest of the script. This anonymous predicate captures <vp>T</vp> and <vp>OnDone</vp>.		We have used an anonymous predicate to perform the execution of the rest of the script. This anonymous predicate captures <vp>T</vp> and <vp>OnDone</vp>.

			<noinclude>[[Category:Language Reference Subarticle]]</noinclude>

Thomas Linder Puls: spell & grammar

2008-10-21T11:44:53Z

spell & grammar

← Older revision		Revision as of 13:44, 21 October 2008
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	===== Asynchronous callbacks =====		===== Asynchronous callbacks =====

	Assume that we send commands to a remote service. The command execution is ~~asynchron-ous~~, so when we execute a command we also give a callback action which will be invoked when the execution of the command is finished. To execute a command we must call this predicate:		Assume that we send commands to a remote service. The command execution is asynchronous, so when we execute a command we also give a callback action which will be invoked when the execution of the command is finished. To execute a command we must call this predicate:

	<vip>predicates		<vip>predicates

SergeMukhin: /* Background treads */

2008-10-18T11:43:36Z

Background treads

← Older revision		Revision as of 13:43, 18 October 2008
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	As mentioned a very powerful feature of anonymous predicates is the ability to capture context. The examples in this section show some ways you can use this.		As mentioned a very powerful feature of anonymous predicates is the ability to capture context. The examples in this section show some ways you can use this.

	===== Background ~~treads~~ =====		===== Background threads =====

	The routine for starting a thread takes a null-ary predicate and run it in the new thread. But you nearly always need to pass some input data to the job in the new thread.		The routine for starting a thread takes a null-ary predicate and run it in the new thread. But you nearly always need to pass some input data to the job in the new thread.
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	<vip>domains		<vip>domains
	job = (jobLog Log).		job = (jobLog Log).</vip>
	A jobLog looks like this:		A jobLog looks like this:
	interface jobLog		<vip>interface jobLog

	properties		properties

SergeMukhin: /* Sorting */

2008-10-18T11:39:07Z

Sorting

← Older revision		Revision as of 13:39, 18 October 2008
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	Sorted = sortBy(C, List),		Sorted = sortBy(C, List),
	write(Label, "\n"),		write(Label, "\n"),
	foreach S = getMember_nd(Sorted) do		foreach S = list::getMember_nd(Sorted) do
	writef(" %\n", S)		writef(" %\n", S)
	end foreach.</vip>		end foreach.</vip>
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	<vip>domains		<vip>domains
	person = p(string First, string Last).		person = p(string First, string Last).</vip>
	For the demonstration we will use this test predicate:		For the demonstration we will use this test predicate:
	class predicates		<vip>class predicates
	writePersonsSorted :		writePersonsSorted :
	(string Label, comparator{person} Comparator).		(string Label, comparator{person} Comparator).
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	Sorted = sortBy(C, List),		Sorted = sortBy(C, List),
	write(Label, "\n"),		write(Label, "\n"),
	foreach p(F,L) = getMember_nd(Sorted) do		foreach p(F,L) = list::getMember_nd(Sorted) do
	writef(" % %\n", F, L)		writef(" % %\n", F, L)
	end foreach.</vip>		end foreach.</vip>
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	Uma Thurman		Uma Thurman
	John Wayne</source>		John Wayne</source>


	===== Capturing context =====		===== Capturing context =====