87 lines
2.3 KiB
Swift
87 lines
2.3 KiB
Swift
import Foundation
|
|
|
|
|
|
class FilterExpression : Resolvable {
|
|
let filters: [Filter]
|
|
let variable: Variable
|
|
|
|
init(token: String, parser: TokenParser) throws {
|
|
let bits = token.componentsSeparatedByString("|")
|
|
if bits.isEmpty {
|
|
filters = []
|
|
variable = Variable("")
|
|
throw TemplateSyntaxError("Variable tags must include at least 1 argument")
|
|
}
|
|
|
|
variable = Variable(bits[0])
|
|
let filterBits = bits[1 ..< bits.endIndex]
|
|
|
|
do {
|
|
filters = try filterBits.map { try parser.findFilter($0) }
|
|
} catch {
|
|
filters = []
|
|
throw error
|
|
}
|
|
}
|
|
|
|
func resolve(context: Context) -> Any? {
|
|
let result = variable.resolve(context)
|
|
|
|
return filters.reduce(result) { x, y in
|
|
return y(x)
|
|
}
|
|
}
|
|
}
|
|
|
|
/// A structure used to represent a template variable, and to resolve it in a given context.
|
|
public struct Variable : Equatable, Resolvable {
|
|
public let variable:String
|
|
|
|
/// Create a variable with a string representing the variable
|
|
public init(_ variable:String) {
|
|
self.variable = variable
|
|
}
|
|
|
|
private func lookup() -> [String] {
|
|
return variable.componentsSeparatedByString(".")
|
|
}
|
|
|
|
/// Resolve the variable in the given context
|
|
public func resolve(context:Context) -> Any? {
|
|
var current:AnyObject? = context
|
|
|
|
if (variable.hasPrefix("'") && variable.hasSuffix("'")) || (variable.hasPrefix("\"") && variable.hasSuffix("\"")) {
|
|
// String literal
|
|
return variable[variable.startIndex.successor() ..< variable.endIndex.predecessor()]
|
|
}
|
|
|
|
for bit in lookup() {
|
|
if let context = current as? Context {
|
|
current = context[bit]
|
|
} else if let dictionary = current as? [String:AnyObject] {
|
|
current = dictionary[bit]
|
|
} else if let array = current as? [AnyObject] {
|
|
if let index = Int(bit) {
|
|
current = array[index]
|
|
} else if bit == "first" {
|
|
current = array.first
|
|
} else if bit == "last" {
|
|
current = array.last
|
|
} else if bit == "count" {
|
|
current = array.count
|
|
}
|
|
} else if let object = current as? NSObject {
|
|
current = object.valueForKey(bit)
|
|
} else {
|
|
return nil
|
|
}
|
|
}
|
|
|
|
return current
|
|
}
|
|
}
|
|
|
|
public func ==(lhs:Variable, rhs:Variable) -> Bool {
|
|
return lhs.variable == rhs.variable
|
|
}
|