-
-
Save dansimpson/5d49439d0f5cfe1f73a3f0fc80ccdf9b to your computer and use it in GitHub Desktop.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
class ResultError < Exception; end | |
abstract class Result(V, E) | |
abstract def unwrap : V | |
abstract def error : E | |
abstract def ok? : Bool | |
abstract def error? : Bool | |
abstract def and_then(&block : V -> Result(V, E)) : Result(V, E) | |
abstract def or_else(&block : E -> Result(V, E)) : Result(V, E) | |
abstract def if_present(&block : V -> Void) : Result(V, E) | |
abstract def map(&block : V -> U) : Result(U, E) forall U | |
class Ok(V, E) < Result(V, E) | |
protected def initialize(@value : V) | |
end | |
def unwrap : V | |
@value | |
end | |
def error : E | |
raise ResultError.new("Ok has no error") | |
end | |
def ok? : Bool | |
true | |
end | |
def error? : Bool | |
false | |
end | |
def and_then(&block : V -> Result(U, E)) : Result(U, E) forall U | |
yield unwrap | |
end | |
def or_else(&block : E -> Void) : self | |
self | |
end | |
def if_present(&block : V -> Void) : self | |
yield unwrap | |
self | |
end | |
def map(&block : V -> U) : Result(U, E) forall U | |
Result(U, E).ok(yield unwrap) | |
end | |
def log! | |
Log.info { "Ok: #{unwrap}" } | |
end | |
end | |
class Error(V, E) < Result(V, E) | |
protected def initialize(@error : E) | |
end | |
def error : E | |
@error | |
end | |
def unwrap : V | |
raise ResultError.new("Error has no value") | |
end | |
def ok? : Bool | |
false | |
end | |
def error? : Bool | |
true | |
end | |
def if_present(&block : V -> Void) : self | |
self | |
end | |
def and_then(&block : V -> Result(U, E)) : Result(U, E) forall U | |
Result(U, E).error(error) | |
end | |
def or_else(&block : E -> Void) : self | |
yield error | |
self | |
end | |
def map(&block : V -> U) : Result(U, E) forall U | |
Result(U, E).error(error) | |
end | |
def log! | |
Log.error { "Error: #{unwrap}" } | |
end | |
end | |
def self.ok(value : V) : self | |
Ok(V, E).new(value) | |
end | |
def self.error(error : E) : self | |
Error(V, E).new(error) | |
end | |
end | |
alias StringResult = Result(String, Exception) |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment