Module prelude 

The standard library of the walking skeleton.

Small on purpose. §3.2’s promise is that “effect polymorphism is what keeps one standard library” — map : (list[a], (a -> b ! e)) -> list[b] ! e. Phase 2 has effect rows, so that signature is now written as written: map_list is polymorphic in what its function argument does, and mapping an effectful function over a list is effectful in exactly that way. One library, one definition per operation, usable from any tier the placement solver allows.

The rows here are the source of truth for inference. Prim::effects is the same information for the atoms a primitive performs itself, and a test holds the two in agreement.

Everything here is a Prim, which means the evaluator implements it and the eventual Cranelift/LLVM backends implement it — never a Beck-source shim that would have to be compiled twice.

Constants

NUM

The trait +, -, * and / resolve through.

Functions

builtin_arity

The type-constructor arities the checker knows without a declaration.

num_method

Which method of NUM an operator is.

prims

Every primitive’s name and type.

traits

The traits every program has.

types

Types every program has: Option, Result, Envelope, Session, Proposal.