54 lines
1.8 KiB
Swift
54 lines
1.8 KiB
Swift
import Foundation
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/// A structure used to represent a template variable, and to resolve it in a given context.
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public struct Variable : Equatable {
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public let variable:String
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/// Create a variable with a string representing the variable
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public init(_ variable:String) {
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self.variable = variable
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}
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private func lookup() -> [String] {
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return variable.componentsSeparatedByString(".")
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}
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/// Resolve the variable in the given context
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public func resolve(context:Context) -> AnyObject? {
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var current:AnyObject? = context
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if (variable.hasPrefix("'") && variable.hasSuffix("'")) || (variable.hasPrefix("\"") && variable.hasSuffix("\"")) {
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return variable.substringWithRange(variable.startIndex.successor() ..< variable.endIndex.predecessor())
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}
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for bit in lookup() {
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if let context = current as? Context {
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current = context[bit]
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} else if let dictionary = current as? Dictionary<String, AnyObject> {
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current = dictionary[bit]
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} else if let array = current as? [AnyObject] {
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if let index = bit.toInt() {
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current = array[index]
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} else if bit == "first" {
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current = array.first
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} else if bit == "last" {
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current = array.last
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} else if bit == "count" {
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current = count(array)
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}
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} else if let object = current as? NSObject {
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current = object.valueForKey(bit)
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} else {
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return nil
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}
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}
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return current
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}
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}
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public func ==(lhs:Variable, rhs:Variable) -> Bool {
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return lhs.variable == rhs.variable
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}
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