Alter AST to Support Set/Stream Policies And Rule Out Hierarchical EDF Policies #55
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KabirSamsi
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Nov 6, 2024
### Background #55 discusses a need for a modified AST that distinguishes between **set-to-stream** and **stream-to-stream** policies, and furthermore distinguishes between **sets** and **streams**. Within that, we discuss the need for a `Union` operator, which effectively 'merges several classes into one'. This is critical in the construction of Set-to-Stream transformers, to allow such polices to arbitrate independent of queue distinctions. ### Overview My work on the type system in #63 allowed us to realize that we could turn typechecking into essentially an abstraction, and have our `set` and `stream` types inferred at parsing-time itself – that is to say, with a tweak to the AST and extending it to the parser as well. That's the first part part of the PR, which entails adding in the `Union` constructor to the AST, and partitioning it into the `set` and `stream` types. ### Caveat And Explanation @polybeandip and I discussed how far we thought this change should extend. On one hand, modifying `Ast.t` contractually requires us to modify `Policy.t`. An alternative, though, is to simply establish a correspondence `Ast.t -> Policy.t`. For simplicity and to preserve the work done in `control`, we have kept `Policy.t` in its original form, and adapted that correspondence. In turn, this required modifying almost all of our programs such that they would be syntactically correct w.rt. the new AST structure and parsing mechanisms. In addition, a few extra 'reversions' to allow for parsed programs to be correctly evaluated in `control`. --------- Co-authored-by: grp loaner <grploaner@users-MacBook-Air.local>
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Per our discussion in #51, we should reduce any lack of clarity in popping order with EDFs. Instead, we need to modify our language's AST such that the EDF and FIFO (possibly SJN, discus later) policies interpolate only between leaves, rather than between internal subtrees.
Add an operator
Union : clss list -> clssto the DSL, which merges a set classes together.The text was updated successfully, but these errors were encountered: