Agent - Revision history

Hzwakenberg at 16:38, 17 June 2016

2016-06-17T16:38:51Z

← Older revision		Revision as of 18:38, 17 June 2016
Line 60:		Line 60:
	make		make
	do		do
−	io.put_string("Sum of all naturals divisible ~~for~~ 3 or 5 lower than 1000 is: ")	+	io.put_string("Sum of all naturals divisible by 3 or 5 lower than 1000 is: ")
	io.put_line((low \|..\| high).aggregate(		io.put_line((low \|..\| high).aggregate(
	agent (progressive, i: INTEGER): INTEGER		agent (progressive, i: INTEGER): INTEGER

Hzwakenberg at 16:36, 17 June 2016

2016-06-17T16:36:05Z

← Older revision		Revision as of 18:36, 17 June 2016
Line 41:		Line 41:
	* beware of automatically allocated pointers for outside local variables, especially if the GC is not used. There is no such problem for arguments since their value cannot change throughout the execution of the outside feature		* beware of automatically allocated pointers for outside local variables, especially if the GC is not used. There is no such problem for arguments since their value cannot change throughout the execution of the outside feature
	* expanded arguments are twinned in the inline agent context (of course)		* expanded arguments are twinned in the inline agent context (of course)
		+
		+	== Example: agent iterating over a range ==
		+
		+	class EULERO
		+	--
		+	-- Project Euler Question 1
		+	-- https://projecteuler.net/problem=1
		+	--
		+
		+	create {ANY}
		+	make
		+
		+	feature {ANY}
		+	low: INTEGER 1
		+
		+	high: INTEGER 999
		+
		+	make
		+	do
		+	io.put_string("Sum of all naturals divisible for 3 or 5 lower than 1000 is: ")
		+	io.put_line((low \|..\| high).aggregate(
		+	agent (progressive, i: INTEGER): INTEGER
		+	do
		+	if i.divisible(3) or i.divisible(5) then
		+	Result := progressive + i
		+	else
		+	Result := progressive
		+	end
		+	end (?, ?), 0).out)
		+	end
		+
		+	end -- class EULERO

Hzwakenberg at 09:58, 17 June 2016

2016-06-17T09:58:49Z

← Older revision		Revision as of 11:58, 17 June 2016
Line 5:		Line 5:
	The agent mechanism gives the Eiffel object-oriented language the ability to handle operations, or commands, as such, like in functional programming languages.		The agent mechanism gives the Eiffel object-oriented language the ability to handle operations, or commands, as such, like in functional programming languages.

−	Agents are a new type of objects that allow to store code to be executed ~~and~~ its data into an object, named the agent. In Eiffel, four types of agents exist: a deferred type [[library_class:ROUTINE\|<tt>ROUTINE</tt>]], and three concrete types [[library_class:PROCEDURE\|<tt>PROCEDURE</tt>]], [[library_class:FUNCTION\|<tt>FUNCTION</tt>]] and [[library_class:PREDICATE\|<tt>PREDICATE</tt>]].	+	Agents are a new type of objects that allow to store the code to be executed together with its data into an object, named the agent. In Eiffel, four types of agents exist: a deferred type [[library_class:ROUTINE\|<tt>ROUTINE</tt>]], and three concrete types [[library_class:PROCEDURE\|<tt>PROCEDURE</tt>]], [[library_class:FUNCTION\|<tt>FUNCTION</tt>]] and [[library_class:PREDICATE\|<tt>PREDICATE</tt>]].

	The following figure shows their inheritance relationship:		The following figure shows their inheritance relationship:

Hzwakenberg: /* Overview */

2016-06-17T09:57:13Z

Overview

← Older revision		Revision as of 11:57, 17 June 2016
Line 5:		Line 5:
	The agent mechanism gives the Eiffel object-oriented language the ability to handle operations, or commands, as such, like in functional programming languages.		The agent mechanism gives the Eiffel object-oriented language the ability to handle operations, or commands, as such, like in functional programming languages.

−	Agents are a new type of objects that allow to store code to be executed and data in an object, named the agent. In Eiffel, four types of agents exist: a deferred type [[library_class:ROUTINE\|<tt>ROUTINE</tt>]], and three concrete types [[library_class:PROCEDURE\|<tt>PROCEDURE</tt>]], [[library_class:FUNCTION\|<tt>FUNCTION</tt>]] and [[library_class:PREDICATE\|<tt>PREDICATE</tt>]].	+	Agents are a new type of objects that allow to store code to be executed and its data into an object, named the agent. In Eiffel, four types of agents exist: a deferred type [[library_class:ROUTINE\|<tt>ROUTINE</tt>]], and three concrete types [[library_class:PROCEDURE\|<tt>PROCEDURE</tt>]], [[library_class:FUNCTION\|<tt>FUNCTION</tt>]] and [[library_class:PREDICATE\|<tt>PREDICATE</tt>]].

	The following figure shows their inheritance relationship:		The following figure shows their inheritance relationship:
Line 11:		Line 11:
	[[File:Agents-fig1.png]]		[[File:Agents-fig1.png]]

−	Agents are a way of storing operations for later execution. They are objects. As such, they can be stored, compared to <tt>Void</tt>, or passed around to other software components. The operation stored in the agent may then be executed whenever the component decides. The most common uses of agents ~~comprise~~ delayed calls, multiple calls (on different values), lazy evaluation, and so on.	+	Agents are a way of storing operations for later execution. They are objects. As such, they can be stored, compared to <tt>Void</tt>, or passed around to other software components. The operation stored in the agent may then be executed whenever the component decides to do so. The most common uses of agents are delayed calls, multiple calls (on different values), lazy evaluation, and so on.

	== Conformance rules ==		== Conformance rules ==

Cadrian: /* Conformance rules */

2013-11-20T14:26:54Z

Conformance rules

← Older revision		Revision as of 16:26, 20 November 2013
Line 23:		Line 23:
	The [[library_class:FUNCTION\|<tt>FUNCTION</tt>]] type inherits from [[library_class:ROUTINE\|<tt>ROUTINE</tt>]], and has two formal type parameters: [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[OPEN –> </tt>[[library_class:TUPLE\|<tt>TUPLE</tt>]]<tt>, RESULT_TYPE]</tt>. According to the conformance rule for generic types, a type [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[O1, R1]</tt> conforms to a type [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[O2, R2]</tt> only if <tt>O2</tt> conforms to <tt>O1</tt> and <tt>R1</tt> conforms to <tt>R2</tt>.		The [[library_class:FUNCTION\|<tt>FUNCTION</tt>]] type inherits from [[library_class:ROUTINE\|<tt>ROUTINE</tt>]], and has two formal type parameters: [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[OPEN –> </tt>[[library_class:TUPLE\|<tt>TUPLE</tt>]]<tt>, RESULT_TYPE]</tt>. According to the conformance rule for generic types, a type [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[O1, R1]</tt> conforms to a type [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[O2, R2]</tt> only if <tt>O2</tt> conforms to <tt>O1</tt> and <tt>R1</tt> conforms to <tt>R2</tt>.

−	[[library_class:PREDICATE\|<tt>PREDICATE</tt>]]<tt>[B, O]</tt> type being just a shortcut for [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[O, </tt>[[library_class:BOOLEAN\|<tt>BOOLEAN</tt>]]<tt>]</tt>, and it has the same conformance rules as [[library_class:FUNCTION\|<tt>FUNCTION</tt>]].	+	[[library_class:PREDICATE\|<tt>PREDICATE</tt>]]<tt>[O]</tt> type being just a shortcut for [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[O, </tt>[[library_class:BOOLEAN\|<tt>BOOLEAN</tt>]]<tt>]</tt>, and it has the same conformance rules as [[library_class:FUNCTION\|<tt>FUNCTION</tt>]].

	'''Note:''' You must be aware of the conformance inversion for the open arguments [[library_class:TUPLE\|tuple]]. See http://www.jot.fm/issues/issue_2004_04/article7/ for the rationale.		'''Note:''' You must be aware of the conformance inversion for the open arguments [[library_class:TUPLE\|tuple]]. See http://www.jot.fm/issues/issue_2004_04/article7/ for the rationale.

Cadrian: /* Conformance rules */

2013-11-20T14:06:30Z

Conformance rules

← Older revision		Revision as of 16:06, 20 November 2013
Line 17:		Line 17:
	The [[library_class:ROUTINE\|<tt>ROUTINE</tt>]] types are generic types with more semantic. As [[library_class:ROUTINE\|<tt>ROUTINE</tt>]] types do not have their own conformance rules one may think that the generic types rules apply. We will hold true this assumption in this chapter, and show that we can make dogs eat tomatoes.		The [[library_class:ROUTINE\|<tt>ROUTINE</tt>]] types are generic types with more semantic. As [[library_class:ROUTINE\|<tt>ROUTINE</tt>]] types do not have their own conformance rules one may think that the generic types rules apply. We will hold true this assumption in this chapter, and show that we can make dogs eat tomatoes.

−	The [[library_class:ROUTINE\|<tt>ROUTINE</tt>]] type is a generic type with one formal type parameter: [[library_class:ROUTINE\|<tt>ROUTINE</tt>]]<tt>[OPEN -> </tt>[[library_class:TUPLE\|<tt>TUPLE</tt>]]<tt>]</tt>. A type [[library_class:ROUTINE\|<tt>ROUTINE</tt>]]<tt>[O1]</tt> conforms to a type [[library_class:ROUTINE\|<tt>ROUTINE</tt>]]<tt>[O2]</tt> only if O2 conforms to O1.	+	The [[library_class:ROUTINE\|<tt>ROUTINE</tt>]] type is a generic type with one formal type parameter: [[library_class:ROUTINE\|<tt>ROUTINE</tt>]]<tt>[OPEN -> </tt>[[library_class:TUPLE\|<tt>TUPLE</tt>]]<tt>]</tt>. A type [[library_class:ROUTINE\|<tt>ROUTINE</tt>]]<tt>[O1]</tt> conforms to a type [[library_class:ROUTINE\|<tt>ROUTINE</tt>]]<tt>[O2]</tt> only if <tt>O2</tt> conforms to <tt>O1</tt>.

	The [[library_class:PROCEDURE\|<tt>PROCEDURE</tt>]] type inherits from [[library_class:ROUTINE\|<tt>ROUTINE</tt>]], and has the same formal type parameter: [[library_class:PROCEDURE\|<tt>PROCEDURE</tt>]]<tt>[OPEN –> </tt>[[library_class:TUPLE\|<tt>TUPLE</tt>]]<tt>]</tt>. Its conformance rule is thus the same as for [[library_class:ROUTINE\|<tt>ROUTINE</tt>]].		The [[library_class:PROCEDURE\|<tt>PROCEDURE</tt>]] type inherits from [[library_class:ROUTINE\|<tt>ROUTINE</tt>]], and has the same formal type parameter: [[library_class:PROCEDURE\|<tt>PROCEDURE</tt>]]<tt>[OPEN –> </tt>[[library_class:TUPLE\|<tt>TUPLE</tt>]]<tt>]</tt>. Its conformance rule is thus the same as for [[library_class:ROUTINE\|<tt>ROUTINE</tt>]].

−	The [[library_class:FUNCTION\|<tt>FUNCTION</tt>]] type inherits from [[library_class:ROUTINE\|<tt>ROUTINE</tt>]], and has two formal type parameters: [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[OPEN –> </tt>[[library_class:TUPLE\|<tt>TUPLE</tt>]]<tt>, RESULT_TYPE]</tt>. According to the conformance rule for generic types, a type [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[O1, R1]</tt> conforms to a type [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[O2, R2]</tt> only if O2 conforms to O1 and R1 conforms to R2.	+	The [[library_class:FUNCTION\|<tt>FUNCTION</tt>]] type inherits from [[library_class:ROUTINE\|<tt>ROUTINE</tt>]], and has two formal type parameters: [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[OPEN –> </tt>[[library_class:TUPLE\|<tt>TUPLE</tt>]]<tt>, RESULT_TYPE]</tt>. According to the conformance rule for generic types, a type [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[O1, R1]</tt> conforms to a type [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[O2, R2]</tt> only if <tt>O2</tt> conforms to <tt>O1</tt> and <tt>R1</tt> conforms to <tt>R2</tt>.

	[[library_class:PREDICATE\|<tt>PREDICATE</tt>]]<tt>[B, O]</tt> type being just a shortcut for [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[O, </tt>[[library_class:BOOLEAN\|<tt>BOOLEAN</tt>]]<tt>]</tt>, and it has the same conformance rules as [[library_class:FUNCTION\|<tt>FUNCTION</tt>]].		[[library_class:PREDICATE\|<tt>PREDICATE</tt>]]<tt>[B, O]</tt> type being just a shortcut for [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[O, </tt>[[library_class:BOOLEAN\|<tt>BOOLEAN</tt>]]<tt>]</tt>, and it has the same conformance rules as [[library_class:FUNCTION\|<tt>FUNCTION</tt>]].

Cadrian at 14:05, 20 November 2013

2013-11-20T14:05:43Z

← Older revision		Revision as of 16:05, 20 November 2013
Line 1:		Line 1:
	In Eiffel, the notion of agent makes it possible to describe and manipulate computation parts (i.e. operations) like ordinary data. Operations may be partially described, may be passed as ordinary data and may have their execution delayed. Agents are very convenient for many purposes, such as going through data structures and implementing call-backs in graphical libraries.		In Eiffel, the notion of agent makes it possible to describe and manipulate computation parts (i.e. operations) like ordinary data. Operations may be partially described, may be passed as ordinary data and may have their execution delayed. Agents are very convenient for many purposes, such as going through data structures and implementing call-backs in graphical libraries.
−
−	See http://www.jot.fm/issues/issue_2004_04/article7/ — some parts are reused here.

	== Overview ==		== Overview ==
Line 7:		Line 5:
	The agent mechanism gives the Eiffel object-oriented language the ability to handle operations, or commands, as such, like in functional programming languages.		The agent mechanism gives the Eiffel object-oriented language the ability to handle operations, or commands, as such, like in functional programming languages.

−	Agents are a new type of objects that allow to store code to be executed and data in an object, named the agent. In Eiffel, four types of agents exist: an ~~abstract (~~deferred) type ROUTINE, and three concrete types PROCEDURE, FUNCTION and PREDICATE. ~~The following figure shows their inheritance relationship:~~	+	Agents are a new type of objects that allow to store code to be executed and data in an object, named the agent. In Eiffel, four types of agents exist: a deferred type [[library_class:ROUTINE\|<tt>ROUTINE</tt>]], and three concrete types [[library_class:PROCEDURE\|<tt>PROCEDURE</tt>]], [[library_class:FUNCTION\|<tt>FUNCTION</tt>]] and [[library_class:PREDICATE\|<tt>PREDICATE</tt>]].
		+
		+	The following figure shows their inheritance relationship:

	[[File:Agents-fig1.png]]		[[File:Agents-fig1.png]]

−	Agents are a way of storing operations for later execution. They are objects. As such, they can be stored, compared to Void, or passed around to other software components. The operation stored in the agent may then be executed whenever the component decides. The most common uses of agents comprise delayed calls, multiple calls (on different values), lazy evaluation, and so on.	+	Agents are a way of storing operations for later execution. They are objects. As such, they can be stored, compared to <tt>Void</tt>, or passed around to other software components. The operation stored in the agent may then be executed whenever the component decides. The most common uses of agents comprise delayed calls, multiple calls (on different values), lazy evaluation, and so on.
		+
		+	== Conformance rules ==
		+
		+	The [[library_class:ROUTINE\|<tt>ROUTINE</tt>]] types are generic types with more semantic. As [[library_class:ROUTINE\|<tt>ROUTINE</tt>]] types do not have their own conformance rules one may think that the generic types rules apply. We will hold true this assumption in this chapter, and show that we can make dogs eat tomatoes.
		+
		+	The [[library_class:ROUTINE\|<tt>ROUTINE</tt>]] type is a generic type with one formal type parameter: [[library_class:ROUTINE\|<tt>ROUTINE</tt>]]<tt>[OPEN -> </tt>[[library_class:TUPLE\|<tt>TUPLE</tt>]]<tt>]</tt>. A type [[library_class:ROUTINE\|<tt>ROUTINE</tt>]]<tt>[O1]</tt> conforms to a type [[library_class:ROUTINE\|<tt>ROUTINE</tt>]]<tt>[O2]</tt> only if O2 conforms to O1.
		+
		+	The [[library_class:PROCEDURE\|<tt>PROCEDURE</tt>]] type inherits from [[library_class:ROUTINE\|<tt>ROUTINE</tt>]], and has the same formal type parameter: [[library_class:PROCEDURE\|<tt>PROCEDURE</tt>]]<tt>[OPEN –> </tt>[[library_class:TUPLE\|<tt>TUPLE</tt>]]<tt>]</tt>. Its conformance rule is thus the same as for [[library_class:ROUTINE\|<tt>ROUTINE</tt>]].
		+
		+	The [[library_class:FUNCTION\|<tt>FUNCTION</tt>]] type inherits from [[library_class:ROUTINE\|<tt>ROUTINE</tt>]], and has two formal type parameters: [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[OPEN –> </tt>[[library_class:TUPLE\|<tt>TUPLE</tt>]]<tt>, RESULT_TYPE]</tt>. According to the conformance rule for generic types, a type [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[O1, R1]</tt> conforms to a type [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[O2, R2]</tt> only if O2 conforms to O1 and R1 conforms to R2.
		+
		+	[[library_class:PREDICATE\|<tt>PREDICATE</tt>]]<tt>[B, O]</tt> type being just a shortcut for [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[O, </tt>[[library_class:BOOLEAN\|<tt>BOOLEAN</tt>]]<tt>]</tt>, and it has the same conformance rules as [[library_class:FUNCTION\|<tt>FUNCTION</tt>]].
		+
		+	'''Note:''' You must be aware of the conformance inversion for the open arguments [[library_class:TUPLE\|tuple]]. See http://www.jot.fm/issues/issue_2004_04/article7/ for the rationale.

	== Inline agents ==		== Inline agents ==
		+
		+	''> '''NB:''' The following will apply from the Bell release onwards. In Adler, inline agents are just anonymous features.''

	Inline agents are closures: they may access the arguments and local variables defined in their outside feature (called ''outside variables'').		Inline agents are closures: they may access the arguments and local variables defined in their outside feature (called ''outside variables'').

Cadrian at 12:44, 20 November 2013

2013-11-20T12:44:48Z

← Older revision		Revision as of 14:44, 20 November 2013
Line 12:		Line 12:

	Agents are a way of storing operations for later execution. They are objects. As such, they can be stored, compared to Void, or passed around to other software components. The operation stored in the agent may then be executed whenever the component decides. The most common uses of agents comprise delayed calls, multiple calls (on different values), lazy evaluation, and so on.		Agents are a way of storing operations for later execution. They are objects. As such, they can be stored, compared to Void, or passed around to other software components. The operation stored in the agent may then be executed whenever the component decides. The most common uses of agents comprise delayed calls, multiple calls (on different values), lazy evaluation, and so on.
−

	== Inline agents ==		== Inline agents ==

Cadrian at 12:44, 20 November 2013

2013-11-20T12:44:31Z

← Older revision		Revision as of 14:44, 20 November 2013
Line 1:		Line 1:
	In Eiffel, the notion of agent makes it possible to describe and manipulate computation parts (i.e. operations) like ordinary data. Operations may be partially described, may be passed as ordinary data and may have their execution delayed. Agents are very convenient for many purposes, such as going through data structures and implementing call-backs in graphical libraries.		In Eiffel, the notion of agent makes it possible to describe and manipulate computation parts (i.e. operations) like ordinary data. Operations may be partially described, may be passed as ordinary data and may have their execution delayed. Agents are very convenient for many purposes, such as going through data structures and implementing call-backs in graphical libraries.

−	See http://www.jot.fm/issues/issue_2004_04/article7/	+	See http://www.jot.fm/issues/issue_2004_04/article7/ — some parts are reused here.

		+	== Overview ==
−	(to be completed)
		+
		+	The agent mechanism gives the Eiffel object-oriented language the ability to handle operations, or commands, as such, like in functional programming languages.
		+
		+	Agents are a new type of objects that allow to store code to be executed and data in an object, named the agent. In Eiffel, four types of agents exist: an abstract (deferred) type ROUTINE, and three concrete types PROCEDURE, FUNCTION and PREDICATE. The following figure shows their inheritance relationship:
		+
		+	[[File:Agents-fig1.png]]
		+
		+	Agents are a way of storing operations for later execution. They are objects. As such, they can be stored, compared to Void, or passed around to other software components. The operation stored in the agent may then be executed whenever the component decides. The most common uses of agents comprise delayed calls, multiple calls (on different values), lazy evaluation, and so on.

Cadrian at 10:54, 20 November 2013

2013-11-20T10:54:03Z

← Older revision		Revision as of 12:54, 20 November 2013
Line 1:		Line 1:
		+	In Eiffel, the notion of agent makes it possible to describe and manipulate computation parts (i.e. operations) like ordinary data. Operations may be partially described, may be passed as ordinary data and may have their execution delayed. Agents are very convenient for many purposes, such as going through data structures and implementing call-backs in graphical libraries.
−	Agents are objects that allow to defer computation.

		+	See http://www.jot.fm/issues/issue_2004_04/article7/
−	(to be completed)

		+	(to be completed)

← Older revision		Revision as of 16:26, 20 November 2013
Line 23:		Line 23:
	The [[library_class:FUNCTION\|<tt>FUNCTION</tt>]] type inherits from [[library_class:ROUTINE\|<tt>ROUTINE</tt>]], and has two formal type parameters: [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[OPEN –> </tt>[[library_class:TUPLE\|<tt>TUPLE</tt>]]<tt>, RESULT_TYPE]</tt>. According to the conformance rule for generic types, a type [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[O1, R1]</tt> conforms to a type [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[O2, R2]</tt> only if <tt>O2</tt> conforms to <tt>O1</tt> and <tt>R1</tt> conforms to <tt>R2</tt>.		The [[library_class:FUNCTION\|<tt>FUNCTION</tt>]] type inherits from [[library_class:ROUTINE\|<tt>ROUTINE</tt>]], and has two formal type parameters: [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[OPEN –> </tt>[[library_class:TUPLE\|<tt>TUPLE</tt>]]<tt>, RESULT_TYPE]</tt>. According to the conformance rule for generic types, a type [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[O1, R1]</tt> conforms to a type [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[O2, R2]</tt> only if <tt>O2</tt> conforms to <tt>O1</tt> and <tt>R1</tt> conforms to <tt>R2</tt>.

−	[[library_class:PREDICATE\|<tt>PREDICATE</tt>]]<tt>[B, O]</tt> type being just a shortcut for [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[O, </tt>[[library_class:BOOLEAN\|<tt>BOOLEAN</tt>]]<tt>]</tt>, and it has the same conformance rules as [[library_class:FUNCTION\|<tt>FUNCTION</tt>]].	+	[[library_class:PREDICATE\|<tt>PREDICATE</tt>]]<tt>[O]</tt> type being just a shortcut for [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[O, </tt>[[library_class:BOOLEAN\|<tt>BOOLEAN</tt>]]<tt>]</tt>, and it has the same conformance rules as [[library_class:FUNCTION\|<tt>FUNCTION</tt>]].

	'''Note:''' You must be aware of the conformance inversion for the open arguments [[library_class:TUPLE\|tuple]]. See http://www.jot.fm/issues/issue_2004_04/article7/ for the rationale.		'''Note:''' You must be aware of the conformance inversion for the open arguments [[library_class:TUPLE\|tuple]]. See http://www.jot.fm/issues/issue_2004_04/article7/ for the rationale.

← Older revision		Revision as of 16:06, 20 November 2013
Line 17:		Line 17:
	The [[library_class:ROUTINE\|<tt>ROUTINE</tt>]] types are generic types with more semantic. As [[library_class:ROUTINE\|<tt>ROUTINE</tt>]] types do not have their own conformance rules one may think that the generic types rules apply. We will hold true this assumption in this chapter, and show that we can make dogs eat tomatoes.		The [[library_class:ROUTINE\|<tt>ROUTINE</tt>]] types are generic types with more semantic. As [[library_class:ROUTINE\|<tt>ROUTINE</tt>]] types do not have their own conformance rules one may think that the generic types rules apply. We will hold true this assumption in this chapter, and show that we can make dogs eat tomatoes.

−	The [[library_class:ROUTINE\|<tt>ROUTINE</tt>]] type is a generic type with one formal type parameter: [[library_class:ROUTINE\|<tt>ROUTINE</tt>]]<tt>[OPEN -> </tt>[[library_class:TUPLE\|<tt>TUPLE</tt>]]<tt>]</tt>. A type [[library_class:ROUTINE\|<tt>ROUTINE</tt>]]<tt>[O1]</tt> conforms to a type [[library_class:ROUTINE\|<tt>ROUTINE</tt>]]<tt>[O2]</tt> only if O2 conforms to O1.	+	The [[library_class:ROUTINE\|<tt>ROUTINE</tt>]] type is a generic type with one formal type parameter: [[library_class:ROUTINE\|<tt>ROUTINE</tt>]]<tt>[OPEN -> </tt>[[library_class:TUPLE\|<tt>TUPLE</tt>]]<tt>]</tt>. A type [[library_class:ROUTINE\|<tt>ROUTINE</tt>]]<tt>[O1]</tt> conforms to a type [[library_class:ROUTINE\|<tt>ROUTINE</tt>]]<tt>[O2]</tt> only if <tt>O2</tt> conforms to <tt>O1</tt>.

	The [[library_class:PROCEDURE\|<tt>PROCEDURE</tt>]] type inherits from [[library_class:ROUTINE\|<tt>ROUTINE</tt>]], and has the same formal type parameter: [[library_class:PROCEDURE\|<tt>PROCEDURE</tt>]]<tt>[OPEN –> </tt>[[library_class:TUPLE\|<tt>TUPLE</tt>]]<tt>]</tt>. Its conformance rule is thus the same as for [[library_class:ROUTINE\|<tt>ROUTINE</tt>]].		The [[library_class:PROCEDURE\|<tt>PROCEDURE</tt>]] type inherits from [[library_class:ROUTINE\|<tt>ROUTINE</tt>]], and has the same formal type parameter: [[library_class:PROCEDURE\|<tt>PROCEDURE</tt>]]<tt>[OPEN –> </tt>[[library_class:TUPLE\|<tt>TUPLE</tt>]]<tt>]</tt>. Its conformance rule is thus the same as for [[library_class:ROUTINE\|<tt>ROUTINE</tt>]].

−	The [[library_class:FUNCTION\|<tt>FUNCTION</tt>]] type inherits from [[library_class:ROUTINE\|<tt>ROUTINE</tt>]], and has two formal type parameters: [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[OPEN –> </tt>[[library_class:TUPLE\|<tt>TUPLE</tt>]]<tt>, RESULT_TYPE]</tt>. According to the conformance rule for generic types, a type [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[O1, R1]</tt> conforms to a type [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[O2, R2]</tt> only if O2 conforms to O1 and R1 conforms to R2.	+	The [[library_class:FUNCTION\|<tt>FUNCTION</tt>]] type inherits from [[library_class:ROUTINE\|<tt>ROUTINE</tt>]], and has two formal type parameters: [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[OPEN –> </tt>[[library_class:TUPLE\|<tt>TUPLE</tt>]]<tt>, RESULT_TYPE]</tt>. According to the conformance rule for generic types, a type [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[O1, R1]</tt> conforms to a type [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[O2, R2]</tt> only if <tt>O2</tt> conforms to <tt>O1</tt> and <tt>R1</tt> conforms to <tt>R2</tt>.

	[[library_class:PREDICATE\|<tt>PREDICATE</tt>]]<tt>[B, O]</tt> type being just a shortcut for [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[O, </tt>[[library_class:BOOLEAN\|<tt>BOOLEAN</tt>]]<tt>]</tt>, and it has the same conformance rules as [[library_class:FUNCTION\|<tt>FUNCTION</tt>]].		[[library_class:PREDICATE\|<tt>PREDICATE</tt>]]<tt>[B, O]</tt> type being just a shortcut for [[library_class:FUNCTION\|<tt>FUNCTION</tt>]]<tt>[O, </tt>[[library_class:BOOLEAN\|<tt>BOOLEAN</tt>]]<tt>]</tt>, and it has the same conformance rules as [[library_class:FUNCTION\|<tt>FUNCTION</tt>]].