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String == operator overload [message #1065540]

Wed, 26 June 2013 12:18

claudio rosati

Messages: 5
Registered: June 2013

Junior Member

Hi everybody, I'm just a beginner on xtext and I'm trying to develop a really easy DSL for "rule editing".

I've a lot of questions, but googling around I'm answering them one at a time.
At the moment I've a problem I'm getting stuck with (and google doesn't seem to have an answer): the overloading of the '==' operator of strings.

Given this code:

if ( riskClass == 'RK1' ) c12 = 0.9000
	else if ( riskClass > 'RK2' ) c12 = 0.1000

the engine generates this java output via model inferrer:

  public void op_0() {
    boolean _equals = void.equal(this.riskClass, "RK1");
    if (_equals) {
      this.c12 = 0.9000;
    } else {
      boolean _greaterThan = (this.riskClass.compareTo("RK2") > 0);
      if (_greaterThan) {
        this.c12 = 0.1000;
      }
    }
  }

It seems that the engine manages without problems the overloading of ">" and ">" or "<="... but the engine misses the overloading of "==" and refers to void.equal(this.riskClass, "RK1").

For clarity here is the inferrer code:

var method = toMethod("op_" + i, newTypeRef(Void::TYPE)) [					    			
  body = operazione.op
]

where operazione.op is an XExpression

The grammar is the following:

grammar com.armundia.quotr.QtrDsl with org.eclipse.xtext.xbase.Xbase
import "http://www.eclipse.org/xtext/common/JavaVMTypes" as types
generate qtrDsl "..."

Model:
rules+=Rule*;

Rule:
'rule' name=ID 
dichiarazioni+=Dichiarazione*		
operazioni+=Operazione*	
'end rule';

Dichiarazione:
Variabile|VariabileInput;

Variabile:	
'outputvar' name=ValidID (':' type=JvmTypeReference)? ('=' right=XExpression)?;

VariabileInput:
'inputvar' name=ValidID (':' type=JvmTypeReference)? ('=' right=XExpression)?;

Operazione:
op=XExpression;

Result:
ret=XReturnExpression;

I've included on the runtime eclipse the library:

org.eclipse.xtext.xbase.lib_2.4.1.v201304180855.jar

Waiting to be more helpful on the list, thanks for the help

Claudio

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Re: String == operator overload [message #1065590 is a reply to message #1065540]

Wed, 26 June 2013 15:26

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

Hi

i dont get this it is intended todo an equals.

/**
* The <code>equals</code> operator. This is the equivalent to a null-safe invocation of
* {@link Object#equals(Object)}.
*
* @param a
* an object.
* @param b
* another object.
* @return <code>true</code> if {@code a} and {@code b} are equal.
*/
@Pure
@Inline(value="$3.equal($1, $2)", imported=Objects.class)
public static boolean operator_equals(Object a, Object b) {
return Objects.equal(a, b);
}

Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

[Updated on: Wed, 26 June 2013 15:31]

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Re: String == operator overload [message #1065594 is a reply to message #1065590]

Wed, 26 June 2013 15:31

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

P.S => Looks like a bug to me (or your classpath is insufficient)

Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

[Updated on: Wed, 26 June 2013 15:35]

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Re: String == operator overload [message #1065596 is a reply to message #1065594]

Wed, 26 June 2013 15:34

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

P.P.S:

com.google.common.base.Objects.equal(Object, Object) should be called.

Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

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Re: String == operator overload [message #1065598 is a reply to message #1065596]

Wed, 26 June 2013 15:36

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

Here a starting point for debugging: org.eclipse.xtext.xbase.compiler.FeatureCallCompiler.appendInlineFeatureCall(XAbstractFeatureCall, ITreeAppendable)

Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

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