grammar org.xtext.example.mydsl.MyDsl with org.eclipse.xtext.common.Terminals

generate myDsl "http://www.xtext.org/example/mydsl/MyDsl"

Model:
	elements+=Element*
	mappings+=Mapping*
;
	
Element:
	"element" name=ID "{"
		attributes+=Attribute*
	"}"
;

Attribute:
	"attr" name=ID
;

Mapping:
	"mapping" from=MappingPart "->" to=MappingPart
;

MappingPart:
	element=[Element] "." attribute=[Attribute]
;

public class MyDslScopeProvider extends AbstractDeclarativeScopeProvider {
	
	public IScope scope_MappingPart_attribute(MappingPart mappingPart, EReference ref) {
		return Scopes.scopeFor(mappingPart.getElement().getAttributes());
	}

}

element A {
	attr a1
	attr a2
}

element B {
	attr b1
	attr b2
}

mapping A.a1 -> B.b2

QualifiedTableReference hidden():ID'.'ID;

QualifiedTable:
name=ID;

QualifiedColumn:
name=ID;

QualifiedTableReference hidden():
	element=[QualifiedTable] "." attribute=[QualifiedColumn];


And ScopeProvider like this
public IScope scope_QualifiedTableReference_attribute(QualifiedTableReference qualifiedTableReference, EReference ref) {
	return Scopes.scopeFor(qualifiedTableReference.getQualifiedTable().getQualifiedColumn());
}

grammar org.xtext.newdef.NewDef with org.eclipse.xtext.common.Terminals

generate newDef "http://www.xtext.org/newdef/NewDef"


Model:
TableDefinitions|NameSpaces;


TableDefinitions:{TableDefinition}'TableDefinitions' tables+=Table*;
Table: name=ID'{'columns+=Column*'}';
Column: name=ID;


NameSpaces:{NameSpaces}
(namespace+=NameSpace)*;

NameSpace:
'Namespace' name=ID "{"
(query+=Query)*
"}";

Query:
'Query' namespace=[NameSpace] ("." name=QualifiedName) "{"
(

("[" 'Description:' description=MYSTRING"]")
&
("[" 'Query:'queryName=[Query|QualifiedName]"]")?
&
("[" 'Filter:' filter+=Filter (',' filter+=Filter)*"]")?
&
//no return fragments yet
("[" 'Return:' return+=ReturnElement (',' return+=ReturnElement)* "]")?
&
("[" 'From:' from=[Table]
joinespression+=JoinExpression*
"]")?
&
("[" 'Where:' where=Where"]")?
&
("[" 'Order:' order+=Order (',' order+=Order)*"]")?)

"}";


Filter: column=ID (multi?='*')?;

ReturnElement: ref=[Column|QualifiedTableReference] ('As' asname=ID)?;

Where: column=[Column|QualifiedTableReference] (expression=WhereExpression)
(("And"|"Or") equals+=ColumnEqualsExpression)*;


Order: ref= [Column|QualifiedTableReference] (direction=Direction)?;
enum Direction: ascending="Asc"|descending="Desc";

JoinExpression: InnerJoinExpression|OuterJoinExpression;

InnerJoinExpression:
(optional?='Optional')? 'Inner' 'Join' jointablename=[Table]
"On" equals+=ColumnRefEqualsExpression
(("And"|"Or") equals+=ColumnEqualsExpression)*;

OuterJoinExpression:
('Optional')? 'Left' 'Join' jointablename=[Table]
"On" equals+=ColumnRefEqualsExpression
(("And"|"Or") equals+=ColumnEqualsExpression)*;


ColumnEqualsExpression:ColumnRefEqualsExpression|ColumnStringEqualsExpression|ColumnOtherExpression;

ColumnRefEqualsExpression: left=[Column|QualifiedTableReference] '=' 
right=[Column|QualifiedTableReference];
ColumnStringEqualsExpression: left=[Column|QualifiedTableReference] ('='|'<>') 
right=STRING;

ColumnOtherExpression: left=[Column|QualifiedTableReference] right=WhereExpression;

WhereExpression: 
IntCompareExpression|NullExpression|NotNullExpression|StringEqualsExpression;

NullExpression: "Is" "Null"{NullExpression};
NotNullExpression: "Is" "Not" "Null"{NotNullExpression};

IntCompareExpression: comparator=Comparator value=INT;
StringEqualsExpression: '=' value=STRING;
enum Comparator: equals = "="| greater=">"|less="<"| 
lessequals="<="|greaterequals= ">="|notequals= "<>";

MYSTRING hidden(): (ID|WS|INT|STRING|'not'|','|ANY_OTHER)*;
QualifiedName hidden():ID('.'ID)*;

//QualifiedTableReference hidden():ID'.'ID;
QualifiedTable:
name=ID;

QualifiedColumn:
name=ID;

QualifiedTableReference hidden():
	element=[QualifiedTable] "." attribute=[QualifiedColumn];

mapping A.a1 -> B.b2  

public IScope scope_MappingPart_attribute(MappingPart mappingPart, EReference ref) {
	return Scopes.scopeFor(mappingPart.getElement().getAttributes());
}

mapping A.a1 -> B.b1

mapping A.b1 -> B.b1

grammar org.xtext.scope.mydsl.MyDsl with org.eclipse.xtext.common.Terminals

generate myDsl "http://www.xtext.org/scope/mydsl/MyDsl"

Model:
	elements+=Element*
	mappings+=Mapping*
;
	
Element:
	"element" name=ID "{"
		attributes+=Attribute*
	"}"
;

Attribute:
	"attr" name=ID
;

Mapping:
	"mapping" from=MappingPart "->" to=MappingPart
;

MappingPart:
	element=[Element] "." attribute=[Attribute]
;

public class MyDslRuntimeModule extends org.xtext.example.mydsl.AbstractMyDslRuntimeModule {
	
	@Override
	public Class<? extends IQualifiedNameProvider> bindIQualifiedNameProvider() {
		return SimpleNameProvider.class;
	}
	

}

grammar org.xtext.example.mydsl.MyDsl with org.eclipse.xtext.common.Terminals

generate myDsl "http://www.xtext.org/example/mydsl/MyDsl"

Model:
	elements+=Element*
	mappings+=Mapping*
;
	
Element:
	"element" name=ID "{"
		attributes+=Attribute*
	"}"
;

Attribute:
	"attr" name=ID
;

Mapping:
	"mapping" from=MappingPart "->" to=MappingPart
;

MappingPart:
	attribute=[Attribute|FQN]
;

FQN: ID ("." ID)*;

QualifiedTableReference hidden():
element=[Table]"."attribute=[Column];

ReturnElement: ref=QualifiedTableReference ('As' asname=ID)?;