option-type

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calling optional delegate methods

i created a delegate for a class @protocol gameDelegate <NSObject> @optional -(void)gameStarted; @required[详细]

2023-01-26 16:02 分类：问答
F# type option problems

i have the following code: let rec sums1 n = function (a,b,x:int array,s,k) when (s<n&&b=x.Length-1) -> []//None[详细]

2023-01-23 17:26 分类：问答
How to retrieve value from optional parser in Parsec?

Sorry if it\'s a novice question - I want to parse something defined by Exp ::= Mandatory_Part Optional_Part0 Optional_Part1[详细]

2023-01-20 12:06 分类：问答
Using Maybe type in Haskell

I\'m trying to utilize the Maybe type in Haskell.I have a lookup for key, value tuples that returns a Maybe.How d开发者_Python百科o I access the data that was wrapped by Maybe?For example I want to ad[详细]

2023-01-14 05:43 分类：问答
Operating on a return from a Maybe that contains "Just"

I have a function that has a return type of Maybe ([(Int,Int)],(Int,Int)) I would like to call this from another function and perform an operation on the data.[详细]

2023-01-09 20:57 分类：问答
Haskell - Use Just or no Just made difference, but I don't know why

I\'ve found such code in the book \"Real World Haskell\", p68 data Tree a = Node a (Tree a) (Tree a) Empty[详细]

2023-01-07 04:34 分类：问答
find whether an element exists by a particular tag name in XML

I have an XML file where some sub tags (child 开发者_开发技巧node elements) are optional. e.g. <part>[详细]

2023-01-06 21:00 分类：问答
Implementing the Haskell-MaybeMonad in F# - how can we get this lazy?

we are trying to build the Haskell-MaybeMonad sample from http://www.haskell.org/all_about_monads/html/maybemonad.html in F#.[详细]

2023-01-05 04:27 分类：问答
reading optional attributes from optional setting in javascript

What is the most efficient way of reading optional attributes in an optional setting argument. I\'m using something like:[详细]

2023-01-04 05:18 分类：问答
Are Maybes a good pattern for scala?

For a while I have been struggling to integrate scala with java methods that might return null.I came up with the following utility w开发者_开发问答hich helps a lot:[详细]

2023-01-01 23:21 分类：问答