F# - Is this a good way to validate and keep a value between two bounds? - validation

Question

I have various values which I would like to keep between certain bounds: e.g. Width of Column from 10 to 50 inclusive; or Number Of Rows from 1 to 100 inclusive. The values are coming from a process external to my F# code.
When a given value falls below the lower bound I would like the value to be given the minimum bound value.
When the given value shoots above the upper bound I would like the value to be given the maximum bound value.
Otherwise I would accept the given value.
For example:
Bounds = 10 to 50 – Given Value = 3 – Result Value = 10
Bounds = 10 to 50 – Given Value = 200 – Result Value = 50
Bounds = 10 to 50 – Given Value = 32 – Result Value = 32
I have come up with some code but I’m not sure if it is taking things too far or whether I am doing it a silly way.
It look like it’s easy to reason how it’s working but I’m not sure about it, for no reason that I can put my finger on.
type ValueAndBounds = { Value : int; Lower : int; Upper: int }
let (|TooSmall|TooLarge|CorrectSize|) input =
if input.Value < input.Lower then TooSmall
elif input.Value > input.Upper then TooLarge
else CorrectSize
let keepWithinBounds input =
match input with
| TooSmall -> input.Lower
| TooLarge -> input.Upper
| CorrectSize -> input.Value
type ColumnWidth = ColumnWidth of int
let width = ColumnWidth (keepWithinBounds { Value = 32; Lower = 10; Upper = 50 })
Is there some way I can improve this?
Have I gone too far for this sort of simple thing (is it more than necessary)?
Is there a better way to do this differently?

Answer 1

personally I'd just define a simple function, and use a bit of partial application,
let keepWithBounds min max value =
if (value < min) then
min
elif (value > max) then
max
else
value
then your code can do something like
let handleWidth = keepWithBounds 10 50
let width1 = handleWidth 32
let width2 = handleWidth 60

Answer 2

Here’s my own answer which uses both active patterns, and partial application, and allows for generic use without the need for an extra type.
let (|TooSmall|TooLarge|CorrectSize|) (lower, upper, input) =
if input < lower then TooSmall
elif input > upper then TooLarge
else CorrectSize
let keepWithinBounds lowerBound upperBound input =
match (lowerBound, upperBound, input) with
| TooSmall -> lowerBound
| TooLarge -> upperBound
| CorrectSize -> input
type ColumnWidth = ColumnWidth of int
type RowHeight = RowHeight of int
type Temperature = Temperature of float
let createColumnWidth = keepWithinBounds 10 40
let createRowHeight = keepWithinBounds 60 100
let createTemperature = keepWithinBounds 0.0 20.0
let width = ColumnWidth (createColumnWidth 50)
let height = RowHeight (createRowHeight 50)
let temp = Temperature (createTemperature 33.1)
//val width : ColumnWidth = ColumnWidth 40
//val height : RowHeight = RowHeight 60
//val temp : Temperature = Temperature 20.0