We are pushing towards a new release (2.0 on its way!!) and we are currently waiting for implementations of the existing PR's. While waiting I took it upon myself to try updating the grammar into a format that is more widely used and easy to understand (EBNF + Antlr4) and I have run into a strange issues around string interpolation.
I have opened a new PR to address these issues! Please review and comment on what you think!
Global String Interpolation:
https://github.com/openwdl/wdl/pull/331
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