Transcript O InterProlog e a Declarativa Miguel Calejo Declarativa

Introducing InterProlog
• Architecture
• Functionality and examples
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From Prolog side
From Java side
A Java-Prolog-Java event roundtrip
Term displayers etc.
• Under the hood
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1st InterProlog architecture - sockets
Terms
Objects
A Java
application
A Prolog
application
InterProlog
classes
InterProlog
predicates
Java VM
Prolog
executable
sockets,
console redirection
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InterProlog architecture (cont.)
• Java/Prolog connection
– Sockets (SubprocessEngine)
• Java program linked to Prolog through I/O and object sockets,
launches “PrologEngines”
– currently XSB, SWI, YAP
– JNI (NativeEngine)
• native methods and built-in predicate for callbacks were added
to XSB Prolog 2.5 and later
• Dynamic Prolog->Java calls using Reflection
• Serialized objects are parsed/generated by a Definite
Clause Grammar :-)
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Yet another use for DCGs :-)
Object network
in memory
JAVA
Serialization
API
Prolog
Term
Stream bytes
InterProlog
Object
Grammar
object(class(...),...data)
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Programming on the Prolog side
• I think I’m under a console process
– The listener window and the first “Hello, World”
?- writeln('Hello, world!').
• javaMessage(Target,Message(Args))
javaMessage( ‘java.lang.System’-out,
println(string(‘hello, world’)) )
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Cynical’s perspective: yet another RPC
Wide open API, as far as Java security allows
Variations handle exceptions, return value, cf. docs
Full version:
javaMessage( Target, Result, Exception, MessageName, ArgList,
NewArgList )
• Needed: a generic approach to specifying objects and basic
type values, stay tuned…
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Object specifications in Prolog
• string(Atom) and 'null'
• ipObjectSpec('InvisibleObject',X,[ID],_)
– Object X should be the object already existing and registered as (int) ID on
the Java side
• ipObjectSpec('IPClassObject',X,[C],_)
– X is the class object for class with name C
• ipObjectSpec('IPClassVariable',X,[C,V],_)
– X is the class variable V of class C
• ipObjectSpec(boolean,X,[B],_)
– X is a boolean basic type for B (which should be 1 or 0); similar
ipObjectSpec facts are available for the remaining basic types: byte, small,
int, long, float, double, char
•
ipObjectSpec(C,X,Variables,_)
– (Generic case) New object X of class C; C must be the fully qualified class
name
– How to add mine? to be seen in Sudoku example
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Hello world, in a window
javaMessage('javax.swing.JFrame',W,'JFrame'(string(myTitle))),
javaMessage(W,C,getContentPane),
javaMessage('javax.swing.JLabel',L,
'JLabel'(string('Hello Prolog, greetings from Swing:-)'))
),
javaMessage(C,add(string('Center'),L)),
javaMessage(W,pack),
javaMessage(W,show).
Note concerning previous slide:
• javaMessage/3 calls ipObjectSpecification/4 before
calling javaMessage/6. A first look at interprolog.P
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Programming on the Java side basics
• 1 PrologEngine <-> 1 XSB (or SWI or YAP) engine
– Implementation restrictions
• Object[] deterministicGoal(
String G, String Ovars, Object[] objectsP, String RVars )
– object specification subgoals must be included in G to accept
objectsP (in Ovars list) and to generate the result (in RVars list)
– Simpler variantes are available, e.g. not requiring input objects or
not returning bindings, cf. Javadoc
• int registerJavaObject(Object x)
– Allow Prolog to refer x by an integer key reference
• interrupt(), shutdown()
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Programming on the Java side
PrologEngine engine = new SWISubprocessEngine();
engine.consultFromJar("test.pl");
/* or consultRelative (to the class location), or
consultAbsolute(File),…*/
Object[] bindings = engine.deterministicGoal(
"descendent_of(X,someAncestor)", "[string(X)]" );
if(bindings!=null){// succeeded
String X = (String)bindings[0];
System.out.println( "X = " + X);
}
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Programming on the Java side
Object[] bindings = engine.deterministicGoal(
“X=string(helloWorld),
ipObjectSpec(‘java.lang.Integer’,Y,[value=13]”,
”[X,Y]”
);
String hw = (String)bindings[0];
Integer lucky = (Integer)bindings[1];
• The deterministicGoal variants
• More examples
– see packages com.declarativa.interprolog.gui,
com.declarativa.interprolog.examples, PrologEngineTest class
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“Hello World”, with a roundtrip
CREATING WINDOW FROM PROLOG:
ipPrologEngine(Engine), javaMessage(
'com.declarativa.interprolog.examples.Hel
loWindow', 'HelloWindow'(Engine))
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Control flow in “Hello World”
a JBu tto n
a JTextFie ld
action Performed()
a
Prolog Even tBro ke r
se tTe xt("He llo World!")
de terministicGo al("g re etat(BUTTONID)")
a Prolo gEng ine
a Callb ackHa nd le r
gree tat(T) :java Me ss ag e(T,string('Hello Wo rld !'))
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Prolog Term displayers
•
browseList([one(X),two(Y),1+1+1,X/Y]).
•
browseLiteralInstances(foo('First','Last'),
[foo('Miguel','Calejo'),foo('Terry','Swift'),foo('David','Warren'),foo('Robert','Pokorn
y')]).
•
browseTreeTerm(t(root,[t(child1,[]),t(child2,[]),t(child3,[t(granchild31,[t(grandgr
andchild311,[])])])])).
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More Prolog support stuff
• The TermModel class
– A convenient way to have Prolog term copies on the Java
side
• Building a Java representation of an arbitrary Prolog
term…
– buildTermModel(Term,TermModel)
• …and vice-versa
– recoverTermModel(TermModel,Term)
• How to write a visual term browser
– Hint: TermModel implements TreeModel
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A larger example:
Sudoku puzzle editor and solver
• Java side
– A Sudoku board in a window (to start, call its constructor)
– SudokuWindow class with inner classes
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SudokuBoard extends JTable
SudokuModel implements TableModel
A few others
Menus call Prolog goals
• Prolog side
– Known numbers Ni in predicate facts n(X,Y,Ni)
– resolve(PlacedNumbers1,PlacedNumbersN)
– Front-end "action" predicates act on current puzzle
• newPuzzle, openPuzzle(File,Array), savePuzzle(File)
• How is data passed between Java and Prolog?
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Getting object specification
predicates from object examples
• Sudoku example uses two object types for
communication:
– int[][] matrix for "bulk assigment" of the whole
board model in one step
– CellValue[] objects, representing a few cells, for
"sparse" (a few at a time) assigment
• Teaching InterProlog about my classes
– teachMoreObjects(ObjectExamplePair[])
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“Under the hood”:
Java package/file structure
• com.declarativa.interprolog
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com.declarativa.interprolog.gui
com.declarativa.interprolog.examples
com.declarativa.interprolog.util
xsb,swi,yap,gnu subdirectories with specific Prolog
file
• com.xsb.interprolog
– NativeEngine and two related classes
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“Under the hood”
• The serialization grammar
• About javaMessage
– javaMessage/2, javaMessage/3, javaMessage/6
– Returning objects rather than references: getRealJavaObject
• A special Java object
– ipPrologEngine(E)
• The deterministicGoal/javaMessage tandem
• Prolog peer classes
– Supporting multiple Prolog systems
– Walkthrough of ipPrologEngine(E),
javaMessage(E,R,getPrologVersion)
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Installation
• Make sure Java and the Prolog systems work
• Download and expand interprolog.zip
• Edit windowsVariables
– There are other ways to let InterProlog find the Prolog
executables
• Running
– Use script to launch listener window
– JUnit test
– Use script to launch your app using the interprolog.jar
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