Joseph Ferano
ed8dbbcd62
The first is CLHS 9.1.4.1: a clause that signalled the condition it handles used to re-enter itself until the stack ran out. The stale list now names a lifted clause by the function it is written in, and BUILT.md's cost line is measured against master.
47 lines
1.6 KiB
Plaintext
47 lines
1.6 KiB
Plaintext
;;;; A program whose callers go stale, for the signature word a dev cell
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;;;; carries (docs/BUILT.md, "A signature change installs").
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;;;;
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;;;; [scale] is the function whose signature the tests change. [step] calls it
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;;;; every frame and [pick] takes it as a value, so both are callers compiled
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;;;; against the signature it starts with — two sites the session has to name
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;;;; after the change, and one the running program has to stop at rather than
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;;;; call. [lonely] has no caller at all, so changing its signature leaves
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;;;; nothing behind.
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;;;;
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;;;; The frame loop's `skip-frame' restart is what the break buffer resumes
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;;;; with once [step] is compiled again. Without it a stale call would have
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;;;; nowhere to go but the exit.
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(import agent "vendor:agent")
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(defonce ticks i64)
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(defonce seen i64)
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(defn scale [x i64] i64 (* x 2))
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(defn step [] i64
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(set ticks (+ ticks 1))
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(set seen (scale ticks))
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seen)
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(defn pick [] (Fn [i64] i64) scale)
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(defn lonely [x i64] i64 x)
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(defn main [] i32
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(agent/start "/tmp/flan-dev-stale-fallback.sock")
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(dotimes [i 6000]
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(agent/wait 5)
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(restart-case (step)
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(skip-frame [] 0)))
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0)
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;;; A stale call inside a handler-bind clause that handles StaleCall. The body's
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;;; call to [scale] signals, the clause runs, and the clause's own call to
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;;; [scale] signals again — which reaches the handlers outside this
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;;; handler-bind and not the clause itself, so it stops in the break buffer
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;;; rather than recursing until the stack runs out. The clause is a lifted
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;;; function, and the stale list names it as [guarded].
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(defn guarded [] i64
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(handler-bind [(StaleCall [c] (set seen (scale 1)))]
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(scale 5)))
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