105 lines
2.2 KiB
Swift
105 lines
2.2 KiB
Swift
import Foundation
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public protocol NodeType {
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/// Render the node in the given context
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func render(_ context:Context) throws -> String
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/// Reference to this node's token
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var token: Token? { get }
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}
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/// Render the collection of nodes in the given context
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public func renderNodes(_ nodes:[NodeType], _ context:Context) throws -> String {
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return try nodes.map({
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do {
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return try $0.render(context)
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} catch {
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throw error.withToken($0.token)
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}
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}).joined(separator: "")
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}
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public class SimpleNode : NodeType {
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public let handler:(Context) throws -> String
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public let token: Token?
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public init(token: Token, handler: @escaping (Context) throws -> String) {
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self.token = token
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self.handler = handler
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}
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public func render(_ context: Context) throws -> String {
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return try handler(context)
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}
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}
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public class TextNode : NodeType {
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public let text:String
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public let token: Token?
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public init(text:String) {
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self.text = text
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self.token = nil
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}
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public func render(_ context:Context) throws -> String {
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return self.text
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}
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}
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public protocol Resolvable {
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func resolve(_ context: Context) throws -> Any?
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}
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public class VariableNode : NodeType {
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public let variable: Resolvable
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public var token: Token?
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public init(variable: Resolvable, token: Token? = nil) {
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self.variable = variable
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self.token = token
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}
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public init(variable: String, token: Token? = nil) {
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self.variable = Variable(variable)
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self.token = token
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}
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public func render(_ context: Context) throws -> String {
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let result = try variable.resolve(context)
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return stringify(result)
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}
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}
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func stringify(_ result: Any?) -> String {
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if let result = result as? String {
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return result
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} else if let array = result as? [Any?] {
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return unwrap(array).description
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} else if let result = result as? CustomStringConvertible {
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return result.description
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} else if let result = result as? NSObject {
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return result.description
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}
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return ""
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}
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func unwrap(_ array: [Any?]) -> [Any] {
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return array.map { (item: Any?) -> Any in
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if let item = item {
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if let items = item as? [Any?] {
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return unwrap(items)
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} else {
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return item
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}
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}
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else { return item as Any }
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}
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}
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