JSSpecCompiler: Add infrastructure to run compiler passes on AST

Meta/Lagom/Tools/CodeGenerators/JSSpecCompiler/Compiler/GenericASTPass.cpp

@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2023, Dan Klishch <danilklishch@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include "Compiler/GenericASTPass.h"
+#include "AST/AST.h"
+#include "Function.h"
+
+namespace JSSpecCompiler {
+
+void RecursiveASTVisitor::run_in_subtree(Tree& tree)
+{
+    NodeSubtreePointer pointer { &tree };
+    recurse(tree, pointer);
+}
+
+void RecursiveASTVisitor::replace_current_node_with(Tree tree)
+{
+    m_current_subtree_pointer->replace_subtree(move(tree));
+}
+
+RecursionDecision RecursiveASTVisitor::recurse(Tree root, NodeSubtreePointer& pointer)
+{
+    RecursionDecision decision;
+
+    m_current_subtree_pointer = &pointer;
+    decision = on_entry(root);
+
+    if (decision == RecursionDecision::Recurse) {
+        for (auto& child : root->subtrees()) {
+            if (recurse(child.get(), child) == RecursionDecision::Break)
+                return RecursionDecision::Break;
+        }
+    }
+
+    m_current_subtree_pointer = &pointer;
+    on_leave(root);
+
+    return RecursionDecision::Continue;
+}
+
+void GenericASTPass::run()
+{
+    run_in_subtree(m_function->m_ast);
+}
+
+}