JetBrains MPS: Typesystem Aspect
- 1. TypeSystem Aspect checking rules checking rules implement semantic error detection either concept or pattern condition whether the rule replaces rules associated with super-concepts block of statements to check error conditions and report errors/warnings message reference to the node that should be highlighted as the source of error editor in use 1 2 3
- 2. TypeSystem Aspect inference rules calculate the types of instance nodes of a concept condition when the inference rule is active either concept or pattern condition not an “assignment operator” 2 3 4 quotation – to create nodes of concepts of a target language BaseLanguage/Java concept “string type” quotation is projected in target language type of a TextField node is BaseLanguage/Java’s string 51
- 3. TypeSystem Aspect inference rules type of an IntegerValue node is BaseLanguage/Java’s int type of a NumberField node is int integer value number field type of a BooleanValue node is boolean type of a ToggleField node is boolean Boolean value toggle field integer Boolean
- 4. TypeSystem Aspect inference rules type of an FieldReference node is the type of the field it refers to establishes a restriction for a type of a certain node type of assigned value should be a (weak) subtype of type of assignee still an inference rule editor in use editor in use 1 2
- 5. Type inference concept UserField instances of entities – fields A x, where A is entity type of user field is a name of an entity extends abstract concept Field and thus can be used whenever a field is expected editor in use fields _a and _b are of type MyEntity 1 2 editor for concept UserField type checking has to be implemented separately now all user fields are implicitly of the same type
- 6. TypeSystem Aspect concept UserField type of user field is type of the entity to which userType refers editor in use 1 2 type of an entity is its name create a “static entity” with the same name “return” this “static entity” as the type of the entity
- 7. Physical units editor in use extends concept IntegerValue style of projected cell “unit” Inspector extends abstract concept Field 1 2 4 5 3 6
- 8. TypeSystem Aspect physical units type of an entity is its name
- 9. TypeSystem Aspect physical units