Added JMESVariable.fromJson, Expression.search(json:)

Author: adam-fowler

Sources/JMESPath/Expression.swift

@@ -1,4 +1,8 @@
+import Foundation
 
+/// JMES Expression
+///
+/// Holds a compiled JMES expression and allows you to search Json text or a structure already in memory
 public struct Expression {
     let ast: Ast
 
@@ -10,11 +14,15 @@ public struct Expression {
         return self.init(ast)
     }
 
-    public func search(_ any: Any) throws -> Any? {
-        let runtime = Runtime()
+    public func search(_ any: Any, runtime: Runtime = .init()) throws -> Any? {
         return try runtime.interpret(JMESVariable(from: any), ast: self.ast).collapse()
     }
 
+    public func search(json: String, runtime: Runtime = .init()) throws -> Any? {
+        let value = try JMESVariable.fromJson(json)
+        return try runtime.interpret(value, ast: self.ast).collapse()
+    }
+
     private init(_ ast: Ast) {
         self.ast = ast
     }

Sources/JMESPath/Functions.swift

@@ -536,8 +536,7 @@ struct ToNumberFunction: Function {
             return .number(number)
         case .string(let string):
             do {
-                let number = try JSONSerialization.jsonObject(with: Data("\(string)".utf8), options: [.allowFragments, .fragmentsAllowed])
-                return try JMESVariable(from: number)
+                return try JMESVariable.fromJson(string)
             } catch {
                 return .null
             }

Sources/JMESPath/JMESVariable.swift

@@ -46,6 +46,11 @@ public enum JMESVariable: Equatable {
         }
     }
 
+    static func fromJson(_ json: String) throws -> Self {
+        let object = try JSONSerialization.jsonObject(with: Data(json.utf8), options: [.fragmentsAllowed])
+        return try JMESVariable(from: object)
+    }
+
     func collapse() -> Any? {
         switch self {
         case .null:

Sources/JMESPath/Lexer.swift

@@ -149,8 +149,9 @@ public class Lexer {
 
     private func readQuotedIdentifier() throws -> String {
         let string = try readInside()
-        let expanded = try JSONSerialization.jsonObject(with: Data("\"\(string)\"".utf8), options: [.allowFragments, .fragmentsAllowed])
-        return expanded as! String
+        let variable = try JMESVariable.fromJson("\"\(string)\"")
+        guard case .string(let string) = variable else { preconditionFailure() }
+        return string
     }
 
     private func readRawString() throws -> JMESVariable {
@@ -162,8 +163,7 @@ public class Lexer {
         let string = try readInside()
         do {
             let unescaped = string.replacingOccurrences(of: "\\`", with: "`")
-            let expanded = try JSONSerialization.jsonObject(with: Data(unescaped.utf8), options: [.allowFragments, .fragmentsAllowed])
-            return try JMESVariable(from: expanded)
+            return try JMESVariable.fromJson(unescaped)
         } catch {
             throw JMESPathError.syntaxError("Unable to parse literal JSON")
         }

Sources/JMESPath/Runtime.swift

@@ -1,16 +1,16 @@
 
 public class Runtime {
-    init() {
+    public init() {
         self.functions = [:]
         self.registerBuiltInFunctions()
     }
 
-    func getFunction(_ name: String) -> Function.Type? {
-        return self.functions[name]
+    public func registerFunction(_ name: String, function: Function.Type) {
+        self.functions[name] = function
     }
 
-    func registerFunction(_ name: String, function: Function.Type) {
-        self.functions[name] = function
+    func getFunction(_ name: String) -> Function.Type? {
+        return self.functions[name]
     }
 
     func registerBuiltInFunctions() {