110 lines
2.3 KiB
Plaintext
110 lines
2.3 KiB
Plaintext
!import "prelude" !Local
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errUnexpectedEof = 1
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errUnexpectedBytes = 2
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errUnexpectedByte = 3
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unit = t
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readU8 = (bytes :
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matchList
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(err errUnexpectedEof t)
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(h r : ok h r)
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bytes)
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readBytes_ self bs n i original acc =
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matchList
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(matchBool
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(ok (reverse acc) bs)
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(err errUnexpectedEof original)
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(equal? i n))
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(h r :
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matchBool
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(ok (reverse acc) bs)
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(self r n (succ i) original (pair h acc))
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(equal? i n))
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bs
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readBytes = (n bs :
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y readBytes_ bs n 0 bs t)
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expectBytes_ self expected bs original =
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matchList
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(ok unit bs)
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(expectedByte expectedRest :
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matchResult
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(code rest : err code original)
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(actual rest :
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matchBool
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(self expectedRest rest original)
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(err errUnexpectedBytes original)
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(equal? actual expectedByte))
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(readU8 bs))
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expected
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expectBytes = (expected bs :
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y expectBytes_ expected bs bs)
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expectU8 = (expected bs :
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matchResult
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(code rest : err code bs)
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(actual rest :
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matchBool
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(ok unit rest)
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(err errUnexpectedByte bs)
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(equal? actual expected))
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(readU8 bs))
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read2 = (bs : readBytes 2 bs)
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read4 = (bs : readBytes 4 bs)
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readU32BEBytes = (bs : read4 bs)
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-- ---------------------------------------------------------------------------
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-- Parser combinators
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-- ---------------------------------------------------------------------------
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pureParser = value bs : ok value bs
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failParser = code bs : err code bs
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mapParser = f p bs : mapResult f (p bs)
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bindParser = p f bs : bindResult (p bs) f
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thenParser = p q bs : bindResult (p bs) (_ : q)
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orParser = (p q bs :
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matchResult
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(_ _ : q bs)
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(value rest : ok value rest)
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(p bs))
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readWhile_ self pred bs acc =
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matchResult
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(code rest : ok (reverse acc) bs)
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(value rest :
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matchBool
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(self pred rest (pair value acc))
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(ok (reverse acc) (pair value rest))
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(pred value))
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(readU8 bs)
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readWhile = pred bs :
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y readWhile_ pred bs t
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readUntil = pred :
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readWhile (x : not? (pred x))
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readRemaining = bs : ok bs t
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peekU8 = (bs :
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matchResult
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(code rest : err code bs)
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(value rest : ok value bs)
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(readU8 bs))
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eof? = (bs :
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matchBool
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(ok t bs)
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(err errUnexpectedEof bs)
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(emptyList? bs))
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expectAscii = expectBytes
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