The mechanical half, ahead of the parser change that needs it. tools/unit-return.py
fills the empty slot with () and rewrites Unit as () wherever a type is spelled --
(Fn [i32] Unit), (Map i32 Unit), a return type written out.
Deciding whether a defn already had a return type is the whole difficulty, and
the script does it the way parse.ml did: is_type_form is transcribed rather than
improved, because being identical to the parser it replaces is what makes the
sweep meaning-preserving. It is re-runnable, so the lanes that branched before
this can have the same pass at merge:
python3 tools/unit-return.py .
python3 tools/unit-return.py --in-strings test/test_flan.ml test/test_acceptance.ml \
test/test_session.ml emacs/test-flan-dev.el emacs/test-flan-mode.el
python3 tools/unit-return.py --raw-ml lib/prelude.ml
python3 tools/unit-return.py --in-html web/index.html
-v logs every defn it saw and what it decided, which is how a sweep of 440 sites
gets reviewed at all. Embedded modes pool a file's type declarations across all
its fragments, because a snippet split across concatenation -- decls ^ "(defn f
[s [u8]] Cursor ...)" -- cannot see the names the other half declared; pooled
names count only in bare-symbol position, for the same reason the prelude's do.
A fragment that cuts off mid-form is skipped rather than guessed at. Five sites
in test_flan.ml still needed a hand, and they are in this commit.
Two things ride along because the sweep needs them: parse.ml reads a lone () as
the return type of a function with no body, which was not a shape the old
optional slot could produce; and the map refusals name () rather than Unit, since
that is now the spelling a caller wrote.
31 lines
667 B
Plaintext
31 lines
667 B
Plaintext
(defconst nums [5 i32] [1 3 8 9 10])
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(defn classify [n i32] string
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(cond
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(< n 0) "negative"
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(= n 0) "zero"
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:else "positive"))
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(defn countdown [n i32] ()
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(let [i n]
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(while (> i 0)
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(print i)
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(print " ")
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(set i (- i 1)))
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(println "")))
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(defn first-even [s [i32]] (Option i32)
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(dotimes [i (len s)]
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(when (= 0 (% (at s i) 2))
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(return (Some (at s i)))))
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None)
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(defn main [] ()
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(println (classify -3))
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(countdown 4)
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(unless false
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(println "unless runs when the test is false"))
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(match (first-even (slice nums 0 (len nums)))
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(Some n) (do (print n) (println ""))
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None (println "none")))
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