Improve range handling (#18)

Author: codeconscious

src/UniqueFileGenerator.Console/Arguments/ArgumentTypes.fs

@@ -15,7 +15,7 @@ module ArgTypes =
     let private tryParseIntInRange (floor, ceiling) text =
         text
         |> parseInRange (floor, ceiling)
-        |> Result.mapError (fun _ -> ParseNumberFailure (text, floor, ceiling))
+        |> Result.mapError (fun _ -> ParseNumberFailure (text, (floor, ceiling)))
 
     type FileCount = private FileCount of int with
         static member val AllowedRange = 1, Int32.MaxValue
@@ -24,9 +24,8 @@ module ArgTypes =
             text
             |> stripSeparators
             |> parseInRange FileCount.AllowedRange
-            |> Result.mapError (fun _ ->
-                ParseNumberFailure (text, fst FileCount.AllowedRange, snd FileCount.AllowedRange))
             |> Result.map FileCount
+            |> Result.mapError (fun _ -> ParseNumberFailure (text, FileCount.AllowedRange))
 
         member this.Value = let (FileCount count) = this in count
 

src/UniqueFileGenerator.Console/Errors.fs

@@ -9,7 +9,7 @@ module Errors =
         | MalformedFlags
         | UnsupportedFlags
         | DuplicateFlags
-        | ParseNumberFailure of Arg: string * Floor: int * Ceiling: int
+        | ParseNumberFailure of Arg: string * AllowedRange: (int * int)
         | DirectoryMissing of string
         | DriveSpaceConfirmationFailure
         | DriveSpaceInsufficient of Needed: string * Actual: string
@@ -23,7 +23,7 @@ module Errors =
         | MalformedFlags -> "Malformed flag(s) found."
         | UnsupportedFlags -> "Unsupported flag(s) found."
         | DuplicateFlags -> "Duplicate option flag(s) found. Each can only be used once."
-        | ParseNumberFailure (x, f, c) ->
+        | ParseNumberFailure (x, (f, c)) ->
             $"Could not parse \"%s{x}\" to an integer between %s{formatInt f} and %s{formatInt c}, inclusive."
         | DirectoryMissing e -> $"Directory \"%s{e}\" was not found."
         | DriveSpaceConfirmationFailure -> "Could not confirm available drive space."

src/UniqueFileGenerator.Tests/ArgParserTests.fs

@@ -64,21 +64,21 @@ let ``Appropriate error when invalid arg count (second pair incomplete)`` () =
 [<Fact>]
 let ``Appropriate error when invalid file count`` () =
     let args = [| "notNumeric" |]
-    let expected = Error <| ParseNumberFailure(args[0], 1, Int32.MaxValue)
+    let expected = Error (ParseNumberFailure(args[0], (1, Int32.MaxValue)))
     let actual = validate args
     Assert.Equal(expected, actual)
 
 [<Fact>]
 let ``Appropriate error when negative file count`` () =
     let args = [| "-1" |]
-    let expected = Error <| ParseNumberFailure(args[0], 1, Int32.MaxValue)
+    let expected = Error (ParseNumberFailure(args[0], (1, Int32.MaxValue)))
     let actual = validate args
     Assert.Equal(expected, actual)
 
 [<Fact>]
 let ``Appropriate error when zero file count`` () =
     let args = [| "0" |]
-    let expected = Error <| ParseNumberFailure(args[0], 1, Int32.MaxValue)
+    let expected = Error (ParseNumberFailure(args[0], (1, Int32.MaxValue)))
     let actual = validate args
     Assert.Equal(expected, actual)