diff options
Diffstat (limited to 'elm.html.markdown')
| -rw-r--r-- | elm.html.markdown | 20 |
1 files changed, 10 insertions, 10 deletions
diff --git a/elm.html.markdown b/elm.html.markdown index ad80adc9..bc7ba4cc 100644 --- a/elm.html.markdown +++ b/elm.html.markdown @@ -224,7 +224,7 @@ List.map : (a -> b) -> List a -> List b -- Comparable allows you to order numbers and strings, like a < b. -- Appendable things can be combined with a ++ b. -{-- Type Aliases and Union Types --} +{-- Type Aliases and Custom Types --} -- When you write a record or tuple, its type already exists. -- (Notice that record types use colon and record values use equals.) @@ -244,28 +244,28 @@ otherOrigin = -- But it's still the same type, so you can equate them. origin == otherOrigin -- True --- By contrast, defining a union type creates a type that didn't exist before. --- A union type is so called because it can be one of many possibilities. --- Each of the possibilities is represented as a "tag". +-- By contrast, defining a custom type creates a type that didn't exist before. +-- A custom type is so called because it can be one of many possibilities. +-- Each of the possibilities is represented as a "type variant". type Direction = North | South | East | West --- Tags can carry other values of known type. This can work recursively. +-- Type variants can carry other values of known type. This can work recursively. type IntTree = Leaf | Node Int IntTree IntTree --- "Leaf" and "Node" are the tags. Everything following a tag is a type. +-- "Leaf" and "Node" are the type variants. Everything following a type variant is a type. --- Tags can be used as values or functions. +-- Type variants can be used as values or functions. root : IntTree root = Node 7 Leaf Leaf --- Union types (and type aliases) can use type variables. +-- Custom types (and type aliases) can use type variables. type Tree a = Leaf | Node a (Tree a) (Tree a) -- "The type tree-of-a is a leaf, or a node of a, tree-of-a, and tree-of-a." --- Pattern match union tags. The uppercase tags will be matched exactly. The +-- Pattern match variants in a custom type. The uppercase variants will be matched exactly. The -- lowercase variables will match anything. Underscore also matches anything, -- but signifies that you aren't using it. leftmostElement : Tree a -> Maybe a @@ -289,7 +289,7 @@ module Name where -- By default, everything is exported. You can specify exports explicitly. module Name (MyType, myValue) where --- One common pattern is to export a union type but not its tags. This is known +-- One common pattern is to export a custom type but not its type variants. This is known -- as an "opaque type", and is frequently used in libraries. -- Import code from other modules to use it in this one. |