Some more work on monads

2 files changed, 33 insertions, 0 deletions

diff --git a/samples/fun/IO.bruijn b/samples/fun/IO.bruijn
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+++ b/samples/fun/IO.bruijn
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+# read two lines using monadic I/O
+# printf "i love\nmonads\n" | bruijn IO.bruijn
+
+:import std/IO .
+
+main read-line >>= [read-line >>= [return [0 2 1]]]
diff --git a/samples/fun/rng-state.bruijn b/samples/fun/rng-state.bruijn
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index 0000000..795bad1
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+++ b/samples/fun/rng-state.bruijn
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+# MIT License, Copyright (c) 2024 Marvin Borner
+# generates three pseudo-random integers using a state monad
+# printf <seed:number> | bruijn rng-state.bruijn
+
+:import std/Combinator .
+:import std/String .
+:import std/Number .
+:import std/Monad/State .
+
+max (+1000)
+
+rand [[[0 1 1]] rng]
+	rng (+1103515245) ⋅ 0 + (+12345) % max
+
+rand-bool map even? rand
+
+# accumulating bind (reversed)
+triple1 rand >>= (rand >>= (rand >>= [[[[[0 3 [0 3 [0 3 [[0]]]]]]]]]))
+
+:test ((triple1 (+50) [[1]]) =? (+745)) ([[1]])
+
+# normal bind
+triple2 rand >>= [rand >>= [rand >>= [[[0 4 [0 4 [0 4 [[0]]]]]]]]]
+
+:test ((triple2 (+50) [[1]]) =? (+595)) ([[1]])
+
+main string→number → triple2