Wdl Versions Save

This is a tag for the main branch of the WDL specification repository prior to the release of WDL 1.1.1.

Going forward, each version of the specification will have its own branch, and the default branch on GitHub will be set to the branch for the current version.

This is a patch release to the WDL 1.1 specification - there are no new features or changes to functionality.

In addition, we are changing to a separate-branch-per-version model for the GitHub repository. The branch for WDL 1.1 will become the repository's default branch.

Changes

• Introduce the concept of "hidden types"; declare that None is of the hidden type Union
• Add clarifications to several sections
• Fix lots of typos
• Organize the standard library hierarchically
• Convert most code examples to test cases

Details can be found in the pull request.