Bugzilla – Full Text Bug Listing
| Summary: | Serializing an expression DSL with parentheses and different operator priorities looses the parentheses | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Product: | [Modeling] TMF | Reporter: | Cedric Vidal <c.vidal> | ||||||||
| Component: | Xtext | Assignee: | Project Inbox <tmf.xtext-inbox> | ||||||||
| Status: | CLOSED FIXED | QA Contact: | |||||||||
| Severity: | major | ||||||||||
| Priority: | P3 | CC: | moritz.eysholdt | ||||||||
| Version: | 1.0.0 | Flags: | moritz.eysholdt:
helios+
moritz.eysholdt: indigo+ |
||||||||
| Target Milestone: | --- | ||||||||||
| Hardware: | PC | ||||||||||
| OS: | Windows 7 | ||||||||||
| Whiteboard: | |||||||||||
| Attachments: |
|
||||||||||
Created attachment 184078 [details]
operator_as_crossref_throws_exception Testcase
Created attachment 184079 [details]
operator_name_as_rule_fails_to_serialize_parentheses Testcase
Created attachment 184080 [details]
operator_name_as_terminal_serializes_fine Testcase
Attached archives contain full projects with a testcase which demonstrate the issue. Fixed in 'master' (1) and 'Helios_Maintenance' (2). The problem was, that the serializer's backtracking algorithm did not take into account whether a cross reference's token complies with the cross reference's terminal- or data type rule. Cedric, thanks for your support. (1): http://git.eclipse.org/c/tmf/org.eclipse.xtext.git/commit/?id=132a8d5d818a97c6b74b24613663fa76e3345f71 (2): http://git.eclipse.org/c/tmf/org.eclipse.xtext.git/commit/?h=Helios_Maintenance&id=298e85916079809a29096049ef302a9ed6a18f51 |
Build Identifier: I20100608-0911 The following grammar serializes correctly: Expression : Addition; Addition returns Expression : Multiplication ({Operation.left=current} op=OPERATOR_ADD right=Multiplication) * ; Multiplication returns Expression : Literal ({Operation.left=current} op=OPERATOR_MUL right=Literal) * ; Literal returns Expression: '(' Expression ')' | {IntLiteral} value=INT ; terminal OPERATOR_MUL : '*'|'/'; terminal OPERATOR_ADD : '+'|'-'; When using rules instead of terminals, serialization fails to include parentheses: Expression : Addition; Addition returns Expression : Multiplication ({Operation.left=current} op=OPERATOR_ADD right=Multiplication) * ; Multiplication returns Expression : Literal ({Operation.left=current} op=OPERATOR_MUL right=Literal) * ; Literal returns Expression: '(' Expression ')' | {IntLiteral} value=INT ; OPERATOR_MUL : '*'|'/'; // <-- using rules instead of terminals OPERATOR_ADD : '+'|'-'; --> parentheses are not serialized When operators are specific meta classes which are referenced, it also fails. The following DSL illustrates that. It adds the possibility to define operators and reference them. Evaluation: (ops+=Operator ';') * 'exp' exp=Expression ; Expression : Addition; Addition returns Expression : Multiplication ({Operation.left=current} op=[Operator|OPERATOR_ADD] right=Multiplication) * ; Multiplication returns Expression : Literal ({Operation.left=current} op=[Operator|OPERATOR_MUL] right=Literal) * ; Literal returns Expression: '(' Expression ')' | {IntLiteral} value=INT ; terminal OPERATOR_MUL : '*'|'/'; terminal OPERATOR_ADD : '+'|'-'; Operator : 'op' name=(OPERATOR_ADD|OPERATOR_MUL) ; --> fails with "org.eclipse.xtext.conversion.ValueConverterException: The value '*' is an invalid OPERATOR_ADD" Reproducible: Always