xtext generator forward input to output

Question

How to forward the part of the parsed tree from input to output in xtend generator?

For instance, in some cases of output code generation, I do not need to parse the parameters of some constructor/functions. I only need to put this constants, variables names, expessions, etc. directly to the output code (forward all inside braces):

input DSL code:

CREATE_OBJECT_O(3, a, 5+6 )

output(may be some Java or C++ code):

Object o = new Object_Impl(3, a, 5+6 )

some part of xtext grammar:

ParameterList:
    (parameter+=Parameter ( "," parameter+=Parameter)* )?
    ;
Parameter:
    variableExpression=VariableExpression |(texts+=TextInParameter | macroSubstitutions+=MacroSubstitution)*;

Zoltán Ujhelyi · Accepted Answer · 2012-10-07T19:24:24.710

There are two different services for doing that in Xtext:

You can inject the org.eclipse.xtext.serializer.ISerializer service, and then call serializer.serialize(EObject) for outputting the object in a textual format. This uses serialization rules, however, if it does not work during editing (e.g. when using inside a JVMModelInferrer).

The class org.eclipse.xtext.nodemodel.util.NodeModelUtils that contains static methods useful here. These methods use the original textual format, keeping the original formatting, so it is usable during editing.

val eObjectNode = NodeModelUtils::getNode(eObject)
eObjectNode.text //this is the output

// Or alternatively getTokenText returns the string without hidden tokens
NodeModelUtils::getTokenText(NodeModelUtils::getNode(eObject))

xtext generator forward input to output

1 Answers1