Initial project import

tools/v/vlib/toml/ast/walker/walker.v

@@ -0,0 +1,70 @@
+module walker
+
+import toml.ast
+
+// Visitor defines a visit method which is invoked by the walker on each Value node it encounters.
+pub interface Visitor {
+	visit(value &ast.Value) !
+}
+
+// Modifier defines a modify method which is invoked by the walker on each Value node it encounters.
+pub interface Modifier {
+	modify(mut value ast.Value) !
+}
+
+pub type InspectorFn = fn (value &ast.Value, data voidptr) !
+
+struct Inspector {
+	inspector_callback InspectorFn = unsafe { nil }
+mut:
+	data voidptr
+}
+
+// visit calls the inspector callback on the specified Value node.
+pub fn (i &Inspector) visit(value &ast.Value) ! {
+	i.inspector_callback(value, i.data) or { return err }
+}
+
+// inspect traverses and checks the AST Value node on a depth-first order and based on the data given
+pub fn inspect(value &ast.Value, data voidptr, inspector_callback InspectorFn) ! {
+	walk(Inspector{inspector_callback, data}, value)!
+}
+
+// walk traverses the AST using the given visitor
+@[autofree_bug; manualfree]
+pub fn walk(visitor Visitor, value &ast.Value) ! {
+	if value is map[string]ast.Value {
+		value_map := value as map[string]ast.Value
+		for _, val in value_map {
+			walk(visitor, &val)!
+		}
+	}
+	if value is []ast.Value {
+		value_array := value as []ast.Value
+		for val in value_array {
+			walk(visitor, &val)!
+		}
+	} else {
+		visitor.visit(value)!
+	}
+}
+
+// walk_and_modify traverses the AST using the given modifier and lets the visitor
+// modify the contents.
+@[autofree_bug; manualfree]
+pub fn walk_and_modify(modifier Modifier, mut value ast.Value) ! {
+	if value is map[string]ast.Value {
+		mut value_map := value as map[string]ast.Value
+		for _, mut val in value_map {
+			walk_and_modify(modifier, mut &val)!
+		}
+	}
+	if value is []ast.Value {
+		mut value_array := value as []ast.Value
+		for mut val in value_array {
+			walk_and_modify(modifier, mut &val)!
+		}
+	} else {
+		modifier.modify(mut value)!
+	}
+}