10 ms·

Everything is an expression (i.e. its an actual functional programming language), and along with it comes a different way of thinking about problems. Coupled wi

Everything is an expression (i.e. its an actual functional programming language), and along with it comes a different way of thinking about problems. Coupled with a really good type system which has discriminated unions, you'll have much fewer bugs. Pro tip: don't write F# like you would write C# - then you might as well write C#. Take the time to learn the functional primitives.

arwhatever 1y ago
if I may elaborate on "everything is an expression," F# allows you to do things like (with apologies for being a tad rusty with the syntax) let bar = if foo then 7 else 11 or let bar = try // code that might throw 7 with ex -> 11 and will ensure that both/all code branches return a compatible type for the `let` binding. Whereas in C# you have to do like int bar; if (foo) { bar = 7; } else { bar = 11; } And C# will let you know if you omit the `else` on accident ... Except that most C# developers do int bar = 0; // or some other default value` to get the red squiggly to go away while they type the rest of the code, unknowingly subverting the compiler's safety check. This doesn't seem like a big deal given these examples. But it becomes a much bigger deal when the if/else grows super large, becomes nested, etc.
- DeathArrow 1y ago
  Also C#: bar = foo switch { true => 7, false => 11 }
  - arwhatever 1y ago
    Ah yes that is definitely a nice addition to the C# language, albeit still with a couple of shortcomings compared to F#: 1. It doesn’t support code blocks, so if you need multiple lines or statements you have to define a function elsewhere. 2. To get exhaustiveness checking on int-backed enums you have to fiddle with compiler preprocessor directives. And for #2 any data associated with each enum variant is left implied by C# and has to be inferred from a reading of the surrounding imperative code, whereas in F# the union data structure makes the relationship explicit, and verifiable by the compiler.

arwhatever 1y ago

if I may elaborate on "everything is an expression," F# allows you to do things like (with apologies for being a tad rusty with the syntax) let bar = if foo then 7 else 11 or let bar = try // code that might throw 7 with ex -> 11 and will ensure that both/all code branches return a compatible type for the `let` binding. Whereas in C# you have to do like int bar; if (foo) { bar = 7; } else { bar = 11; } And C# will let you know if you omit the `else` on accident ... Except that most C# developers do int bar = 0; // or some other default value` to get the red squiggly to go away while they type the rest of the code, unknowingly subverting the compiler's safety check. This doesn't seem like a big deal given these examples. But it becomes a much bigger deal when the if/else grows super large, becomes nested, etc.

DeathArrow 1y ago
Also C#: bar = foo switch { true => 7, false => 11 }
- arwhatever 1y ago
  Ah yes that is definitely a nice addition to the C# language, albeit still with a couple of shortcomings compared to F#: 1. It doesn’t support code blocks, so if you need multiple lines or statements you have to define a function elsewhere. 2. To get exhaustiveness checking on int-backed enums you have to fiddle with compiler preprocessor directives. And for #2 any data associated with each enum variant is left implied by C# and has to be inferred from a reading of the surrounding imperative code, whereas in F# the union data structure makes the relationship explicit, and verifiable by the compiler.