99 lines
2.5 KiB
Text
99 lines
2.5 KiB
Text
inductive DataType
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| TInt
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| TFloat
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| TString
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open DataType
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inductive DataEntry
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| EInt (i : Int)
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| EFloat (f : Float)
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| EString (s : String)
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| NULL
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def NULL := DataEntry.NULL
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instance : Coe Int DataEntry where
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coe := DataEntry.EInt
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instance : Coe Float DataEntry where
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coe := DataEntry.EFloat
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instance : OfNat DataEntry n where
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ofNat := DataEntry.EInt n
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instance : OfScientific DataEntry where
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ofScientific m s e := DataEntry.EFloat (OfScientific.ofScientific m s e)
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instance : Coe String DataEntry where
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coe := DataEntry.EString
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namespace DataEntry
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@[simp] def isOf (e : DataEntry) (t : DataType) : Prop :=
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match e, t with
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| EInt _, TInt => True
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| EFloat _, TFloat => True
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| EString _, TString => True
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| NULL, _ => True
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| _, _ => False
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end DataEntry
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abbrev Header := List (DataType × String)
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def Header.colTypes (h : Header) : List DataType :=
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h.map fun x => x.1
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def Header.colNames (h : Header) : List String :=
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h.map fun x => x.2
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abbrev Row := List DataEntry
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@[simp] def rowOfTypes : Row → List DataType → Prop
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| [], [] => True
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| eh :: et, th :: tt => eh.isOf th ∧ rowOfTypes et tt
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| _, _ => False
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@[simp] def rowsOfTypes : List Row → List DataType → Prop
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| row :: rows, types => rowOfTypes row types ∧ rowsOfTypes rows types
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| [], _ => True
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structure DataFrame where
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header : Header
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rows : List Row
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consistent : rowsOfTypes rows header.colTypes := by simp
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namespace DataFrame
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def empty (header : Header := []) : DataFrame :=
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⟨header, [], by simp⟩
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theorem consistentConcatOfConsistentRow
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{df : DataFrame} (row : List DataEntry)
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(hc : rowOfTypes row df.header.colTypes) :
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rowsOfTypes (df.rows.concat row) (Header.colTypes df.header) :=
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match df with
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| ⟨_, rows, hr⟩ => by
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induction rows with
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| nil => simp at hc; simp [hc]
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| cons _ _ hi => exact ⟨hr.1, hi hr.2 hc⟩
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def addRow (df : DataFrame) (row : List DataEntry)
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(h : rowOfTypes row df.header.colTypes := by simp) : DataFrame :=
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⟨df.header, df.rows.concat row, consistentConcatOfConsistentRow row h⟩
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end DataFrame
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def h : Header := [(TInt, "id"), (TString, "name")]
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def r : List Row := [[1, "alex"]]
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-- this no longer works
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def df1 : DataFrame := DataFrame.mk h r
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-- and this ofc breaks now
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def df2 : DataFrame := df1.addRow [2, "juddy"]
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-- this doesn't work anymore either
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def df3 : DataFrame := DataFrame.empty h |>.addRow [3, "john"]
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