Joseph Ferano
96ab4c9cf0
print-str, print-i64, print-f64, print-bytes, print-line and newline leave the prelude. print and println are the whole printing surface now, and print is the better call at every one of the sites that used them: it is the same structural walk without the newline, so the no-newline case the family was kept for is covered, and it takes the value as it is. The old print-i64 forced an explicit (i64 x) at every call site, because this language widens nothing implicitly; that cast is gone from 127 places. Dropping it moves one answer. hash-grid returns u64, and the cast through the signed printer showed sand-headless's hash as -2851001042534928384. print routes a u64 through flan_u64_to_bytes, so it now prints 15595743031174623232 — the same 64 bits, read as the unsigned number they are. The pinned expectation follows the correction. test-flan-dev.el and test_session.ml both reached for print-line as "a name the prelude has"; they reach for rand-seed instead.
46 lines
1.7 KiB
Plaintext
46 lines
1.7 KiB
Plaintext
;;;; handler-bind and signal — spec-conditions.md §1 and §2.
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;;;;
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;;;; The accumulation case, which is what makes these two worth having on their
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;;;; own: signal returns Unit, a handler that returns normally leaves the
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;;;; signalling function to carry on, and with nothing matching signal is a
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;;;; no-op. No control flow is altered, so none of the transfer machinery
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;;;; restart-case needs exists yet.
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(defstruct AssetMissing [id i32])
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(defstruct Corrupt [id i32])
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(defvar seen i64)
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(defvar other i64)
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;;; Signals twice and keeps going both times — that is the whole of §1.
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(defn load-all []
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(signal (AssetMissing {:id 1}))
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(signal (AssetMissing {:id 2}))
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(signal (Corrupt {:id 3})))
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(defn main [] i32
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;; No handler: a no-op, not an abort and not a message (§2).
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(load-all)
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(print seen) (println "") ; 0
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(handler-bind [(AssetMissing [c] (set seen (+ seen (i64 (.id c)))))]
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(load-all))
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(print seen) (println "") ; 1 + 2 = 3
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;; Two clauses, and only the matching one runs for each condition.
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(handler-bind [(AssetMissing [c] (set seen (+ seen 10)))
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(Corrupt [c] (set other (+ other (i64 (.id c)))))]
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(load-all))
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(print seen) (println "") ; 3 + 20 = 23
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(print other) (println "") ; 3
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;; Nesting: the inner frame does not displace the outer one, so both run.
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(handler-bind [(Corrupt [c] (set other (+ other 100)))]
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(handler-bind [(Corrupt [c] (set other (+ other 1000)))]
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(signal (Corrupt {:id 0}))))
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(print other) (println "") ; 3 + 1000 + 100 = 1103
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;; And the stack is back to what it was: no handler, no effect.
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(load-all)
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(print other) (println "") ; 1103
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0)
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