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danielrbradley/1-plain-function.fs

Created December 9, 2016 15:53
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3 ways of organising F# functions related to a type
Raw
1-plain-function.fs
module VendingMachine
type Coin = Quarter | Dime | Nickel
let valueOf coin =
match coin with
| Quarter -> 0.25m
| Dime -> 0.10m
| Nickel -> 0.05m
Raw
2-members.fs
/// Easier to discover as you can just type a '.' in VS to see options.
/// Downside - '.' breaks the type inference :(
module VendingMachine
type Coin =
| Quarter
| Dime
| Nickel
member this.Value =
match this with
| Quarter -> 0.25m
| Dime -> 0.10m
| Nickel -> 0.05m
Raw
3-matching-module.fs
/// This is a common pattern for F# libraries to follow - to keep the type simple,
/// but make it easy to find associated functions, and gives good type inference.
module VendingMachine
type Coin = Quarter | Dime | Nickel
// The attribute lets us use the same name as the type.
[<CompilationRepresentation(CompilationRepresentationFlags.ModuleSuffix)>]
module Coin =
let value coin =
match coin with
| Quarter -> 0.25m
| Dime -> 0.10m
| Nickel -> 0.05m
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