Joseph Ferano
c604911ecb
Loading a package kept one table, keyed by real path, and used it for two different questions. Already loaded meant "skip", which is right for the second route of a diamond and wrong for a ring: a package that imported itself round a chain met its own entry, contributed nothing, and appeared to work. The comment said so and called it a feature. It is not one. A ring has no package order, and a definite package order is what the macro expander needs — every defmacro has to be compiled before anything that calls it. So the chain currently being read is now carried separately from the set already finished. A directory found in the first is a cycle and is refused; a directory found only in the second is still the diamond's second route and still a no-op. The refusal names the ring — a -> b -> c -> a — and only the ring, not the route that led to it. "There is a cycle" leaves the reader to find which three imports it was. pkgs now comes back dependencies-first, which is the topological order the acyclic rule buys. The declaration list is left alone: check.ml collects every top-level name before it checks any body, so declarations are order-independent by construction and sorting them would be churn in the field every test reads. The tests are a real tree rather than a second copy of pkg-shared. pkg-diamond builds a shape/Box inside area/ and hands it to a function declared inside draw/, which only type-checks if the bottom package was read once — two copies of one struct are two types. What proves it is the numbers, not the compile.
13 lines
501 B
Plaintext
13 lines
501 B
Plaintext
;;;; One middle of the diamond. Imports shape, and hands shape/Box back out.
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;;;;
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;;;; The alias is the *inner* one: this file says shape, and the finished
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;;;; program calls the type shape/Box, not area/shape/Box. A package imported
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;;;; through an intermediate arrives under the name its own importer chose.
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(import shape "../shape")
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(defn of [b shape/Box] i32 (* (.w b) (.h b)))
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;;; A shape/Box made on this side of the diamond, to be read on the other.
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(defn unit [] shape/Box (shape/box 3 2))
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