19 lines
660 B
Plaintext
19 lines
660 B
Plaintext
def join(a, b) {
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# This must not use the builtin if, since it coerces to boolean rather than passing messages.
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# false.pick(x, y) returns y and true.pick(x, y) returns x; we protect the amb([]) from causing
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# unconditional failure by putting both options in functions.
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# <=> is the comparison operator that happens to be message-based.
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return (a.last() <=> b[0]).pick(fn {
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a + " " + b
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}, fn {
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amb([])
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})()
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}
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def w1 := amb(["the", "that", "a" ])
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def w2 := amb(["frog", "elephant", "thing" ])
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def w3 := amb(["walked", "treaded", "grows" ])
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def w4 := amb(["slowly", "quickly" ])
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unamb(join(join(join(w1, w2), w3), w4))
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