diff --git a/cxxheaderparser/gentest.py b/cxxheaderparser/gentest.py
index ace24d7..a738298 100644
--- a/cxxheaderparser/gentest.py
+++ b/cxxheaderparser/gentest.py
@@ -63,7 +63,7 @@ def gentest(
     popt = ""
 
     options = ParserOptions(verbose=verbose)
-    if options:
+    if pcpp:
         options.preprocessor = make_pcpp_preprocessor()
         maybe_options = "options = ParserOptions(preprocessor=make_pcpp_preprocessor())"
         popt = ", options=options"
diff --git a/cxxheaderparser/parser.py b/cxxheaderparser/parser.py
index 0fed1c2..1fd0fa8 100644
--- a/cxxheaderparser/parser.py
+++ b/cxxheaderparser/parser.py
@@ -58,7 +58,7 @@ from .types import (
     Value,
     Variable,
 )
-from .visitor import CxxVisitor
+from .visitor import CxxVisitor, null_visitor
 
 LexTokenList = typing.List[LexToken]
 T = typing.TypeVar("T")
@@ -114,6 +114,7 @@ class CxxParser:
 
     def _push_state(self, cls: typing.Type[ST], *args) -> ST:
         state = cls(self.state, *args)
+        state._prior_visitor = self.visitor
         if isinstance(state, NamespaceBlockState):
             self.current_namespace = state.namespace
         self.state = state
@@ -122,6 +123,7 @@ class CxxParser:
     def _pop_state(self) -> State:
         prev_state = self.state
         prev_state._finish(self.visitor)
+        self.visitor = prev_state._prior_visitor
         state = prev_state.parent
         if state is None:
             raise CxxParseError("INTERNAL ERROR: unbalanced state")
@@ -454,7 +456,8 @@ class CxxParser:
         ns = NamespaceDecl(names, inline, doxygen)
         state = self._push_state(NamespaceBlockState, ns)
         state.location = location
-        self.visitor.on_namespace_start(state)
+        if self.visitor.on_namespace_start(state) is False:
+            self.visitor = null_visitor
 
     def _parse_extern(self, tok: LexToken, doxygen: typing.Optional[str]) -> None:
         etok = self.lex.token_if("STRING_LITERAL", "template")
@@ -463,7 +466,8 @@ class CxxParser:
                 if self.lex.token_if("{"):
                     state = self._push_state(ExternBlockState, etok.value)
                     state.location = tok.location
-                    self.visitor.on_extern_block_start(state)
+                    if self.visitor.on_extern_block_start(state) is False:
+                        self.visitor = null_visitor
                     return
 
                 # an extern variable/function with specific linkage
@@ -508,7 +512,8 @@ class CxxParser:
         self, tok: LexToken, doxygen: typing.Optional[str]
     ) -> None:
         state = self._push_state(EmptyBlockState)
-        self.visitor.on_empty_block_start(state)
+        if self.visitor.on_empty_block_start(state) is False:
+            self.visitor = null_visitor
 
     def _on_block_end(self, tok: LexToken, doxygen: typing.Optional[str]) -> None:
         old_state = self._pop_state()
@@ -1143,7 +1148,8 @@ class CxxParser:
             ClassBlockState, clsdecl, default_access, typedef, mods
         )
         state.location = location
-        self.visitor.on_class_start(state)
+        if self.visitor.on_class_start(state) is False:
+            self.visitor = null_visitor
 
     def _finish_class_decl(self, state: ClassBlockState) -> None:
         self._finish_class_or_enum(
diff --git a/cxxheaderparser/parserstate.py b/cxxheaderparser/parserstate.py
index d2f1a95..86ed2f6 100644
--- a/cxxheaderparser/parserstate.py
+++ b/cxxheaderparser/parserstate.py
@@ -46,6 +46,9 @@ class State(typing.Generic[T, PT]):
     #: Approximate location that the parsed element was found at
     location: Location
 
+    #: internal detail used by parser
+    _prior_visitor: "CxxVisitor"
+
     def __init__(self, parent: typing.Optional["State[PT, typing.Any]"]) -> None:
         self.parent = parent
 
diff --git a/cxxheaderparser/simple.py b/cxxheaderparser/simple.py
index f0ec240..a58191e 100644
--- a/cxxheaderparser/simple.py
+++ b/cxxheaderparser/simple.py
@@ -209,22 +209,24 @@ class SimpleCxxVisitor:
     def on_include(self, state: SState, filename: str) -> None:
         self.data.includes.append(Include(filename))
 
-    def on_empty_block_start(self, state: SEmptyBlockState) -> None:
+    def on_empty_block_start(self, state: SEmptyBlockState) -> typing.Optional[bool]:
         # this matters for some scope/resolving purposes, but you're
         # probably going to want to use clang if you care about that
         # level of detail
         state.user_data = state.parent.user_data
+        return None
 
     def on_empty_block_end(self, state: SEmptyBlockState) -> None:
         pass
 
-    def on_extern_block_start(self, state: SExternBlockState) -> None:
+    def on_extern_block_start(self, state: SExternBlockState) -> typing.Optional[bool]:
         state.user_data = state.parent.user_data
+        return None
 
     def on_extern_block_end(self, state: SExternBlockState) -> None:
         pass
 
-    def on_namespace_start(self, state: SNamespaceBlockState) -> None:
+    def on_namespace_start(self, state: SNamespaceBlockState) -> typing.Optional[bool]:
         parent_ns = state.parent.user_data
 
         ns = None
@@ -247,6 +249,7 @@ class SimpleCxxVisitor:
         ns.doxygen = state.namespace.doxygen
 
         state.user_data = ns
+        return None
 
     def on_namespace_end(self, state: SNamespaceBlockState) -> None:
         pass
@@ -299,11 +302,12 @@ class SimpleCxxVisitor:
     # Class/union/struct
     #
 
-    def on_class_start(self, state: SClassBlockState) -> None:
+    def on_class_start(self, state: SClassBlockState) -> typing.Optional[bool]:
         parent = state.parent.user_data
         block = ClassScope(state.class_decl)
         parent.classes.append(block)
         state.user_data = block
+        return None
 
     def on_class_field(self, state: SClassBlockState, f: Field) -> None:
         state.user_data.fields.append(f)
diff --git a/cxxheaderparser/visitor.py b/cxxheaderparser/visitor.py
index 6088139..5c17a46 100644
--- a/cxxheaderparser/visitor.py
+++ b/cxxheaderparser/visitor.py
@@ -52,7 +52,7 @@ class CxxVisitor(Protocol):
         Called once for each ``#include`` directive encountered
         """
 
-    def on_empty_block_start(self, state: EmptyBlockState) -> None:
+    def on_empty_block_start(self, state: EmptyBlockState) -> typing.Optional[bool]:
         """
         Called when a ``{`` is encountered that isn't associated with or
         consumed by other declarations.
@@ -62,6 +62,9 @@ class CxxVisitor(Protocol):
             {
                 // stuff
             }
+
+        If this function returns False, the visitor will not be called for any
+        items inside this block (including on_empty_block_end)
         """
 
     def on_empty_block_end(self, state: EmptyBlockState) -> None:
@@ -69,7 +72,7 @@ class CxxVisitor(Protocol):
         Called when an empty block ends
         """
 
-    def on_extern_block_start(self, state: ExternBlockState) -> None:
+    def on_extern_block_start(self, state: ExternBlockState) -> typing.Optional[bool]:
         """
         .. code-block:: c++
 
@@ -77,6 +80,8 @@ class CxxVisitor(Protocol):
 
             }
 
+        If this function returns False, the visitor will not be called for any
+        items inside this block (including on_extern_block_end)
         """
 
     def on_extern_block_end(self, state: ExternBlockState) -> None:
@@ -84,9 +89,12 @@ class CxxVisitor(Protocol):
         Called when an extern block ends
         """
 
-    def on_namespace_start(self, state: NamespaceBlockState) -> None:
+    def on_namespace_start(self, state: NamespaceBlockState) -> typing.Optional[bool]:
         """
         Called when a ``namespace`` directive is encountered
+
+        If this function returns False, the visitor will not be called for any
+        items inside this namespace (including on_namespace_end)
         """
 
     def on_namespace_end(self, state: NamespaceBlockState) -> None:
@@ -186,7 +194,7 @@ class CxxVisitor(Protocol):
     # Class/union/struct
     #
 
-    def on_class_start(self, state: ClassBlockState) -> None:
+    def on_class_start(self, state: ClassBlockState) -> typing.Optional[bool]:
         """
         Called when a class/struct/union is encountered
 
@@ -199,6 +207,9 @@ class CxxVisitor(Protocol):
         This is called first, followed by on_typedef for each typedef instance
         encountered. The compound type object is passed as the type to the
         typedef.
+
+        If this function returns False, the visitor will not be called for any
+        items inside this class (including on_class_end)
         """
 
     def on_class_field(self, state: ClassBlockState, f: Field) -> None:
@@ -231,3 +242,87 @@ class CxxVisitor(Protocol):
         Then ``on_class_start``, .. ``on_class_end`` are emitted, along with
         ``on_variable`` for each instance declared.
         """
+
+
+class NullVisitor:
+    """
+    This visitor does nothing
+    """
+
+    def on_parse_start(self, state: NamespaceBlockState) -> None:
+        return None
+
+    def on_pragma(self, state: State, content: Value) -> None:
+        return None
+
+    def on_include(self, state: State, filename: str) -> None:
+        return None
+
+    def on_empty_block_start(self, state: EmptyBlockState) -> typing.Optional[bool]:
+        return None
+
+    def on_empty_block_end(self, state: EmptyBlockState) -> None:
+        return None
+
+    def on_extern_block_start(self, state: ExternBlockState) -> typing.Optional[bool]:
+        return None
+
+    def on_extern_block_end(self, state: ExternBlockState) -> None:
+        return None
+
+    def on_namespace_start(self, state: NamespaceBlockState) -> typing.Optional[bool]:
+        return None
+
+    def on_namespace_end(self, state: NamespaceBlockState) -> None:
+        return None
+
+    def on_namespace_alias(self, state: State, alias: NamespaceAlias) -> None:
+        return None
+
+    def on_forward_decl(self, state: State, fdecl: ForwardDecl) -> None:
+        return None
+
+    def on_template_inst(self, state: State, inst: TemplateInst) -> None:
+        return None
+
+    def on_variable(self, state: State, v: Variable) -> None:
+        return None
+
+    def on_function(self, state: State, fn: Function) -> None:
+        return None
+
+    def on_method_impl(self, state: State, method: Method) -> None:
+        return None
+
+    def on_typedef(self, state: State, typedef: Typedef) -> None:
+        return None
+
+    def on_using_namespace(self, state: State, namespace: typing.List[str]) -> None:
+        return None
+
+    def on_using_alias(self, state: State, using: UsingAlias) -> None:
+        return None
+
+    def on_using_declaration(self, state: State, using: UsingDecl) -> None:
+        return None
+
+    def on_enum(self, state: State, enum: EnumDecl) -> None:
+        return None
+
+    def on_class_start(self, state: ClassBlockState) -> typing.Optional[bool]:
+        return None
+
+    def on_class_field(self, state: ClassBlockState, f: Field) -> None:
+        return None
+
+    def on_class_friend(self, state: ClassBlockState, friend: FriendDecl) -> None:
+        return None
+
+    def on_class_method(self, state: ClassBlockState, method: Method) -> None:
+        return None
+
+    def on_class_end(self, state: ClassBlockState) -> None:
+        return None
+
+
+null_visitor = NullVisitor()
diff --git a/tests/test_skip.py b/tests/test_skip.py
new file mode 100644
index 0000000..2415e03
--- /dev/null
+++ b/tests/test_skip.py
@@ -0,0 +1,269 @@
+# Note: testcases generated via `python -m cxxheaderparser.gentest`
+# .. and modified
+
+import inspect
+import typing
+
+from cxxheaderparser.parser import CxxParser
+from cxxheaderparser.simple import (
+    ClassScope,
+    NamespaceScope,
+    ParsedData,
+    SClassBlockState,
+    SEmptyBlockState,
+    SExternBlockState,
+    SNamespaceBlockState,
+    SimpleCxxVisitor,
+)
+
+from cxxheaderparser.types import (
+    ClassDecl,
+    Function,
+    FundamentalSpecifier,
+    Method,
+    NameSpecifier,
+    PQName,
+    Type,
+)
+
+#
+# ensure extern block is skipped
+#
+
+
+class SkipExtern(SimpleCxxVisitor):
+    def on_extern_block_start(self, state: SExternBlockState) -> typing.Optional[bool]:
+        return False
+
+
+def test_skip_extern():
+    content = """
+      void fn1();
+
+      extern "C" {
+          void fn2();
+      }
+
+      void fn3();
+    """
+
+    v = SkipExtern()
+    parser = CxxParser("<str>", inspect.cleandoc(content), v)
+    parser.parse()
+    data = v.data
+
+    assert data == ParsedData(
+        namespace=NamespaceScope(
+            functions=[
+                Function(
+                    return_type=Type(
+                        typename=PQName(segments=[FundamentalSpecifier(name="void")])
+                    ),
+                    name=PQName(segments=[NameSpecifier(name="fn1")]),
+                    parameters=[],
+                ),
+                Function(
+                    return_type=Type(
+                        typename=PQName(segments=[FundamentalSpecifier(name="void")])
+                    ),
+                    name=PQName(segments=[NameSpecifier(name="fn3")]),
+                    parameters=[],
+                ),
+            ]
+        )
+    )
+
+
+#
+# ensure class block is skipped
+#
+
+
+class SkipClass(SimpleCxxVisitor):
+    def on_class_start(self, state: SClassBlockState) -> typing.Optional[bool]:
+        if getattr(state.class_decl.typename.segments[0], "name", None) == "Skip":
+            return False
+        return super().on_class_start(state)
+
+
+def test_skip_class() -> None:
+    content = """
+      void fn1();
+
+      class Skip {
+          void fn2();
+      };
+
+      class Yup {
+          void fn3();
+      };
+
+      void fn5();
+    """
+    v = SkipClass()
+    parser = CxxParser("<str>", inspect.cleandoc(content), v)
+    parser.parse()
+    data = v.data
+
+    assert data == ParsedData(
+        namespace=NamespaceScope(
+            classes=[
+                ClassScope(
+                    class_decl=ClassDecl(
+                        typename=PQName(
+                            segments=[NameSpecifier(name="Yup")], classkey="class"
+                        )
+                    ),
+                    methods=[
+                        Method(
+                            return_type=Type(
+                                typename=PQName(
+                                    segments=[FundamentalSpecifier(name="void")]
+                                )
+                            ),
+                            name=PQName(segments=[NameSpecifier(name="fn3")]),
+                            parameters=[],
+                            access="private",
+                        )
+                    ],
+                ),
+            ],
+            functions=[
+                Function(
+                    return_type=Type(
+                        typename=PQName(segments=[FundamentalSpecifier(name="void")])
+                    ),
+                    name=PQName(segments=[NameSpecifier(name="fn1")]),
+                    parameters=[],
+                ),
+                Function(
+                    return_type=Type(
+                        typename=PQName(segments=[FundamentalSpecifier(name="void")])
+                    ),
+                    name=PQName(segments=[NameSpecifier(name="fn5")]),
+                    parameters=[],
+                ),
+            ],
+        )
+    )
+
+
+#
+# ensure empty block is skipped
+#
+
+
+class SkipEmptyBlock(SimpleCxxVisitor):
+    def on_empty_block_start(self, state: SEmptyBlockState) -> typing.Optional[bool]:
+        return False
+
+
+def test_skip_empty_block() -> None:
+    content = """
+      void fn1();
+
+      {
+          void fn2();
+      }
+
+      void fn3();
+    """
+    v = SkipEmptyBlock()
+    parser = CxxParser("<str>", inspect.cleandoc(content), v)
+    parser.parse()
+    data = v.data
+
+    assert data == ParsedData(
+        namespace=NamespaceScope(
+            functions=[
+                Function(
+                    return_type=Type(
+                        typename=PQName(segments=[FundamentalSpecifier(name="void")])
+                    ),
+                    name=PQName(segments=[NameSpecifier(name="fn1")]),
+                    parameters=[],
+                ),
+                Function(
+                    return_type=Type(
+                        typename=PQName(segments=[FundamentalSpecifier(name="void")])
+                    ),
+                    name=PQName(segments=[NameSpecifier(name="fn3")]),
+                    parameters=[],
+                ),
+            ]
+        )
+    )
+
+
+#
+# ensure namespace 'skip' is skipped
+#
+
+
+class SkipNamespace(SimpleCxxVisitor):
+    def on_namespace_start(self, state: SNamespaceBlockState) -> typing.Optional[bool]:
+        if "skip" in state.namespace.names[0]:
+            return False
+
+        return super().on_namespace_start(state)
+
+
+def test_skip_namespace():
+    content = """
+      void fn1();
+
+      namespace skip {
+          void fn2();
+
+          namespace thistoo {
+              void fn3();
+          }
+      }
+
+      namespace ok {
+          void fn4();
+      }
+
+      void fn5();
+    """
+    v = SkipNamespace()
+    parser = CxxParser("<str>", inspect.cleandoc(content), v)
+    parser.parse()
+    data = v.data
+
+    assert data == ParsedData(
+        namespace=NamespaceScope(
+            functions=[
+                Function(
+                    return_type=Type(
+                        typename=PQName(segments=[FundamentalSpecifier(name="void")])
+                    ),
+                    name=PQName(segments=[NameSpecifier(name="fn1")]),
+                    parameters=[],
+                ),
+                Function(
+                    return_type=Type(
+                        typename=PQName(segments=[FundamentalSpecifier(name="void")])
+                    ),
+                    name=PQName(segments=[NameSpecifier(name="fn5")]),
+                    parameters=[],
+                ),
+            ],
+            namespaces={
+                "ok": NamespaceScope(
+                    name="ok",
+                    functions=[
+                        Function(
+                            return_type=Type(
+                                typename=PQName(
+                                    segments=[FundamentalSpecifier(name="void")]
+                                )
+                            ),
+                            name=PQName(segments=[NameSpecifier(name="fn4")]),
+                            parameters=[],
+                        )
+                    ],
+                ),
+            },
+        )
+    )