29 lines
527 B
Text
29 lines
527 B
Text
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abbrev M := ExceptT String $ ExceptT Nat $ StateM Nat
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def inc (x : Nat) : M Unit := do
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if (← get) >= 100 then
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throwThe Nat ((← get) + x)
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modify (· + x)
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def dec (x : Nat) : M Unit := do
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if (← get) - x == 0 then
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throw "balance is zero"
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modify (· - x)
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def f (x y : Nat) : M Nat := do
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try
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inc x
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dec y
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get
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catch ex : String =>
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dbgTrace! "string exception {ex}"
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pure 1000
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catch ex : Nat =>
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dbgTrace! "nat exception {ex}"
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pure ex
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#eval (f 10 20).run 1000
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#eval (f 10 200).run 10
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#eval (f 10 20).run 30
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