55 lines
1.2 KiB
Hy
55 lines
1.2 KiB
Hy
;; Copyright 2020 the authors.
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;; This file is part of Hy, which is free software licensed under the Expat
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;; license. See the LICENSE.
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(require [hy.contrib.loop [loop]])
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(import sys)
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(defn tco-sum [x y]
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(loop [[x x] [y y]]
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(cond
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[(> y 0) (recur (inc x) (dec y))]
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[(< y 0) (recur (dec x) (inc y))]
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[True x])))
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(defn non-tco-sum [x y]
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(cond
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[(> y 0) (inc (non-tco-sum x (dec y)))]
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[(< y 0) (dec (non-tco-sum x (inc y)))]
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[True x]))
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(defn test-loop []
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;; non-tco-sum should fail
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(try
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(setv n (non-tco-sum 100 10000))
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(except [e RuntimeError]
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(assert True))
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(else
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(assert False)))
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;; tco-sum should not fail
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(try
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(setv n (tco-sum 100 10000))
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(except [e RuntimeError]
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(assert False))
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(else
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(assert (= n 10100)))))
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(defn test-recur-in-wrong-loc []
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(defn bad-recur [n]
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(loop [[i n]]
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(if (= i 0)
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0
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(inc (recur (dec i))))))
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(try
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(bad-recur 3)
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(except [e TypeError]
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(assert True))
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(else
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(assert False))))
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(defn test-recur-string []
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"test that `loop` doesn't touch a string named `recur`"
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(assert (= (loop [] (+ "recur" "1")) "recur1")))
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