54 lines
1.4 KiB
Swift
54 lines
1.4 KiB
Swift
/// A container for template variables.
|
|
public class Context {
|
|
var dictionaries:[[String: Any]]
|
|
|
|
/// Initialise a Context with a dictionary
|
|
public init(dictionary:[String: Any]) {
|
|
dictionaries = [dictionary]
|
|
}
|
|
|
|
/// Initialise an empty Context
|
|
public init() {
|
|
dictionaries = []
|
|
}
|
|
|
|
public subscript(key: String) -> Any? {
|
|
/// Retrieves a variable's value, starting at the current context and going upwards
|
|
get {
|
|
for dictionary in Array(dictionaries.reverse()) {
|
|
if let value = dictionary[key] {
|
|
return value
|
|
}
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
/// Set a variable in the current context, deleting the variable if it's nil
|
|
set(value) {
|
|
if var dictionary = dictionaries.popLast() {
|
|
dictionary[key] = value
|
|
dictionaries.append(dictionary)
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Push a new level into the Context
|
|
public func push(dictionary: [String: Any]? = nil) {
|
|
dictionaries.append(dictionary ?? [:])
|
|
}
|
|
|
|
/// Pop the last level off of the Context
|
|
public func pop() -> [String: Any]? {
|
|
return dictionaries.popLast()
|
|
}
|
|
|
|
/// Push a new level onto the context for the duration of the execution of the given closure
|
|
public func push<Result>(dictionary: [String: Any]? = nil, @noescape closure: (() throws -> Result)) rethrows -> Result {
|
|
push(dictionary)
|
|
let result = try closure()
|
|
pop()
|
|
return result
|
|
}
|
|
}
|