feat(filters): Allow filters with arguments

Sources/Variable.swift

@@ -2,7 +2,7 @@ import Foundation
 
 
 class FilterExpression : Resolvable {
-  let filters: [Filter]
+  let filters: [(FilterType, [Variable])]
   let variable: Variable
 
   init(token: String, parser: TokenParser) throws {
@@ -17,7 +17,11 @@ class FilterExpression : Resolvable {
     let filterBits = bits[bits.indices.suffix(from: 1)]
 
     do {
-      filters = try filterBits.map { try parser.findFilter($0) }
+      filters = try filterBits.map {
+        let (name, arguments) = parseFilterComponents(token: $0)
+        let filter = try parser.findFilter(name)
+        return (filter, arguments)
+      }
     } catch {
       filters = []
       throw error
@@ -28,7 +32,8 @@ class FilterExpression : Resolvable {
     let result = try variable.resolve(context)
 
     return try filters.reduce(result) { x, y in
-      return try y(x)
+      let arguments = try y.1.map { try $0.resolve(context) }
+      return try y.0.invoke(value: x, arguments: arguments)
     }
   }
 }
@@ -135,3 +140,10 @@ extension Dictionary : Normalizable {
     return dictionary
   }
 }
+
+func parseFilterComponents(token: String) -> (String, [Variable]) {
+  var components = token.characters.split(separator: ":").map(String.init)
+  let name = components.removeFirst()
+  let variables = components.joined(separator: ":").characters.split(separator: ",").map { Variable(String($0)) }
+  return (name, variables)
+}