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45 lines
1.4 KiB
Go
45 lines
1.4 KiB
Go
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package readert
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import (
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F "github.com/ibm/fp-go/function"
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R "github.com/ibm/fp-go/reader/generic"
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)
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// here we implement the monadic operations using callbacks from
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// higher kinded types, as good a golang allows use to do this
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func MonadMap[GEA ~func(E) HKTA, GEB ~func(E) HKTB, E, A, B, HKTA, HKTB any](fmap func(HKTA, func(A) B) HKTB, fa GEA, f func(A) B) GEB {
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return R.MonadMap[GEA, GEB](fa, F.Bind2nd(fmap, f))
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}
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func MonadChain[GEA ~func(E) HKTA, GEB ~func(E) HKTB, A, E, HKTA, HKTB any](fchain func(HKTA, func(A) HKTB) HKTB, ma GEA, f func(A) GEB) GEB {
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return R.MakeReader(func(r E) HKTB {
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return fchain(ma(r), func(a A) HKTB {
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return f(a)(r)
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})
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})
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}
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func MonadOf[GEA ~func(E) HKTA, E, A, HKTA any](fof func(A) HKTA, a A) GEA {
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return R.MakeReader(func(_ E) HKTA {
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return fof(a)
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})
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}
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// HKTFAB = HKT[func(A)B]
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func MonadAp[GEA ~func(E) HKTA, GEB ~func(E) HKTB, GEFAB ~func(E) HKTFAB, E, A, HKTA, HKTB, HKTFAB any](fap func(HKTFAB, HKTA) HKTB, fab GEFAB, fa GEA) GEB {
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return R.MakeReader(func(r E) HKTB {
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return fap(fab(r), fa(r))
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})
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}
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func MonadFromReader[GA ~func(E) A, GEA ~func(E) HKTA, E, A, HKTA any](
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fof func(A) HKTA, ma GA) GEA {
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return R.MakeReader(F.Flow2(ma, fof))
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}
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func FromReader[GA ~func(E) A, GEA ~func(E) HKTA, E, A, HKTA any](
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fof func(A) HKTA) func(ma GA) GEA {
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return F.Bind1st(MonadFromReader[GA, GEA, E, A, HKTA], fof)
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}
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