annotate record.ur @ 23:9d6b931fbd13
Implement JSON type class for recursive datatypes, using Mu combinator.
| author |
Edward Z. Yang <ezyang@mit.edu> |
| date |
Wed, 02 May 2012 11:47:37 -0400 |
| parents |
6cd839818393 |
| children |
f55f66c6fdee |
| rev |
line source |
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adam@11
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1 fun numFields [r ::: {Type}] (fl : folder r) (r : $r) : int =
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adam@11
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2 @fold [fn _ => int] (fn [nm ::_] [u ::_] [r ::_] [[nm] ~ r] acc => acc+1) 0 fl
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adam@11
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3
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adam@10
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4 fun mem [a ::: Type] [ns ::: {Unit}] (_ : eq a) (fl : folder ns) (x : a) (r : $(mapU a ns)) : bool =
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adam@10
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5 @foldUR [a] [fn _ => bool]
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adam@10
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6 (fn [nm ::_] [r ::_] [[nm] ~ r] y acc =>
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adam@10
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7 acc || x = y)
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adam@10
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8 False fl r
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adam@12
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9
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adam@12
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10 fun equal [ts ::: {Type}] (eqs : $(map eq ts)) (fl : folder ts) (r1 : $ts) (r2 : $ts) : bool =
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adam@18
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11 @foldR3 [eq] [ident] [ident] [fn _ => bool]
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adam@12
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12 (fn [nm ::_] [t ::_] [r ::_] [[nm] ~ r] isEq x y acc =>
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adam@12
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13 acc && @eq isEq x y)
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adam@12
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14 True fl eqs r1 r2
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