Talk:Dev:Semantic Constraints

Discussion March 2020

Initial question: what are semcons and what are no semcons?

Questions

• Definition
  • Suggestion:
    A semantic constraint is a constraint that cannot be implemented in an XSD.
  • What is obviously a semcon?
  • What is obviously not a semcon?
    • Element semantics and attribute semantics - otherwise every element semantics and attribute semantics would be a semcon (although it may be annoying to put the dead weight under <vehicle>@nettoWeight and the load capacity under <vehicle>@tareWeight).
    • Intentions (about the function of a certain Element/Attribute)
    • Recommendations
    • Best Practices
    • Conclusions from syntactic constraints and/or element/attribute semantics
    • Explanations of semantic constraints
  • Cf. [1]→[2]
• Goals
  • Interoperability?
  • Do they apply to the developer or the user?
  • Who can control/guarantee compliance?
• Design
  • Allow/deny the recycling of discarded numbers?

Creating semantic constraints

• Suggestion and Discussion
  • either in the railML^® Forum
  • or in a railML^® working group
    →in this case the working group must present their discussion result in the forum and grant a term for discussion there
• Enter the semcon with status proposed into the wiki
• If there are no objections, the semcon becomes accepted after a certain term (6 weeks)
• In case of objections the working group decides

Design guidelines

• Use the template with all mandatory arguments
  The template must be extended with an argument to link to the discussion as to grant that the proposal is preceded by a discussion
• Implement a seperate semcon for every rule
• Record on Dev:Semantic_Constraints/table
• numbering according to Dev:Semantic_Constraints/table

Distinctions within element documentation / Structure and usage of an Wiki page

• Position of XYZ in the XML-Tree:
  • Shall contain the position of the element in the XML tree
  • railML^® 2: generated manual by the coordinator straightforward from the schema; no manual additions
  • railML^® 3: generated automatically by GWPS; no manual additions
  • Criteria to be fulfilled for successful certification
• Multiplicity: straightforward from the schema – relevant for certification
• Semantics: Only the intention. No rules or explanations. Concise remarks like “not to be confused with” are allowed, if they explain the intention – not relevant for certification
• Attributes: No rules or explanations. Concise remarks like “not to be confused with” are allowed, if they explain the intention – not relevant for certification
• Syntactic constraints: straightforward from the schema – relevant for certification
• Semantic constraints: compare above – relevant for certification
• Best Practice Examples: for instance national rules and peculiarities; Code examples – not relevant for certification
• Open Issues: open discussions and unsolved problems – not relevant for certification
• Notes: Anything that does not fit into other paragraphs – not relevant for certification

 

Where can you comment on the semantics in wiki3?

GWPS = Gruschwitz' Wonderful Phython Script