Implement builder removal APIs

Sources/SwiftParser/CodeParser.swift

@@ -20,6 +20,14 @@ public final class CodeParser {
         builders.append(builder)
     }
 
+    public func unregister(builder: CodeElementBuilder) {
+        if let target = builder as? AnyObject {
+            if let index = builders.firstIndex(where: { ($0 as? AnyObject) === target }) {
+                builders.remove(at: index)
+            }
+        }
+    }
+
     public func clearBuilders() {
         builders.removeAll()
     }
@@ -28,6 +36,18 @@ public final class CodeParser {
         expressionBuilders.append(expressionBuilder)
     }
 
+    public func unregister(expressionBuilder: CodeExpressionBuilder) {
+        if let target = expressionBuilder as? AnyObject {
+            if let index = expressionBuilders.firstIndex(where: { ($0 as? AnyObject) === target }) {
+                expressionBuilders.remove(at: index)
+            }
+        }
+    }
+
+    public func clearExpressionBuilders() {
+        expressionBuilders.removeAll()
+    }
+
     public func parse(_ input: String, rootNode: CodeNode) -> (node: CodeNode, context: CodeContext) {
         let tokens = tokenizer.tokenize(input)
         var context = CodeContext(tokens: tokens, index: 0, currentNode: rootNode, errors: [], input: input)

Tests/SwiftParserTests/SwiftParserTests.swift

@@ -74,4 +74,40 @@ final class SwiftParserTests: XCTestCase {
         _ = parser.update("x = 2", rootNode: root)
         XCTAssertEqual(root.children.first?.children.first?.value, "2")
     }
+
+    func testUnregisterElementBuilder() {
+        let tokenizer = PythonLanguage.Tokenizer()
+        let expr = PythonLanguage.ExpressionBuilder()
+        let assign = PythonLanguage.AssignmentBuilder(expressionBuilder: expr)
+        let parser = CodeParser(tokenizer: tokenizer)
+        parser.register(builder: assign)
+        parser.register(expressionBuilder: expr)
+
+        let root1 = CodeNode(type: PythonLanguage.Element.root, value: "")
+        _ = parser.parse("x = 1", rootNode: root1)
+        XCTAssertEqual(root1.children.first?.type as? PythonLanguage.Element, .assignment)
+
+        parser.unregister(builder: assign)
+
+        let root2 = CodeNode(type: PythonLanguage.Element.root, value: "")
+        _ = parser.parse("x = 1", rootNode: root2)
+        XCTAssertEqual(root2.children.first?.type as? PythonLanguage.Element, .identifier)
+    }
+
+    func testUnregisterExpressionBuilder() {
+        let tokenizer = PythonLanguage.Tokenizer()
+        let expr = PythonLanguage.ExpressionBuilder()
+        let parser = CodeParser(tokenizer: tokenizer)
+        parser.register(expressionBuilder: expr)
+
+        let root1 = CodeNode(type: PythonLanguage.Element.root, value: "")
+        _ = parser.parse("1 + 2", rootNode: root1)
+        XCTAssertEqual(root1.children.count, 1)
+
+        parser.unregister(expressionBuilder: expr)
+
+        let root2 = CodeNode(type: PythonLanguage.Element.root, value: "")
+        _ = parser.parse("1 + 2", rootNode: root2)
+        XCTAssertEqual(root2.children.count, 0)
+    }
 }