BNF Tools Version 2.0: Migration Notes

Discovered features in version 1.0 and their migration status, as well as further migration notes are summarised below.

Core Features:

1. BNF front-end (Parser, Lexer, Linker, etc.)
2. translates a textual representation into an Ecore model
3. Editor - provides IDE features, e.g. auto-completion, syntax highlighting, etc.

Validation Rules:

These rules will give warnings in the editor if they find find consistencies in the code.

1. checkUpdateGrammarConsistency: checks, if the grammar is an updated grammar, for consistencies between the originals and the new grammar
   • status: not migrated
2. checkReferencedOnlyOnce: this should warn if there is a rule that is only referenced once, this is an inlining hint
   • status: migrated
3. checkPassthroughRule: this tests if a rule gets just passed through, e.g. a ::= b, b ::= "literal" <=> a ::= "literal", which is better for EBNF
   • status: migrated
4. checkEqualAlternative: this tests if a rule got equal alternatives, e.g.: a::= d | d
   • status: migrated
5. checkDuplicateRules: checks if there is another rule in the EtsiBnf, that has the same right hand side, e.g.: a ::= "literal" | b, c ::= "literal" | b
   • status: migrated
6. checkSubruleDuplicates:
   • status: not migrated
7. check unused rule: checks if a rule is used (exept for the rule with the number 1)
   • status: migrated
8. checkNameIsUnique: checks if the name of a rule is already in use e.g. a ::= "end", a ::= "fin"
   • status: migrated

Generation:

Generating an intermediate xsl-fo representation for all BNF grammars (merge or delta grammars not supported). This can be rendered to PDF using apache-fop

• status: in progress

Formatting:

• old: had some but they are got commented out in the main project
• new: line-break after every rule, white-spaces after all literals, possible update linebreak and double tab after all >|< bars

Refactoring and Quick-fixing:

Automated restructuring support.

1. auto Numbering of rules
   • status: not migrated
2. remove unused rules
   • status: migrated
3. replacement of passthroughRules
   • status: not migrated
4. refactor uppercasetokenRules
   • status: not migrated
5. find references
   • status: provided by xtext2
6. renaming
   • status: provided by xtext2

Grammar Composition:

• 3 grammartypes:
  • grammar: normal grammar
  • delta grammar: different notation for a extension grammar,
    • adds new rules to a grammar (regular rules) and adds changes to rules of the extended grammar (extension rules) (can be automatically created)
  • merge grammar: for merging extensions
• old version had an automatic composition process for merge grammars with a small pop-up-menu.

• at the moment no support in the new version

Deployment:

• export project as Plugin: Plug-in Development/deployable plug-ins and fragments
• RCP project with a minimal eclipse editor: TBD