diff --git a/cxxheaderparser/parser.py b/cxxheaderparser/parser.py
index a8cdf95..5bef044 100644
--- a/cxxheaderparser/parser.py
+++ b/cxxheaderparser/parser.py
@@ -25,6 +25,7 @@
Concept,
DecltypeSpecifier,
DecoratedType,
+ DeductionGuide,
EnumDecl,
Enumerator,
Field,
@@ -1868,10 +1869,9 @@ def _parse_parameters(
_auto_return_typename = PQName([AutoSpecifier()])
def _parse_trailing_return_type(
- self, fn: typing.Union[Function, FunctionType]
- ) -> None:
+ self, return_type: typing.Optional[DecoratedType]
+ ) -> DecoratedType:
# entry is "->"
- return_type = fn.return_type
if not (
isinstance(return_type, Type)
and not return_type.const
@@ -1890,8 +1890,7 @@ def _parse_trailing_return_type(
dtype = self._parse_cv_ptr(parsed_type)
- fn.has_trailing_return = True
- fn.return_type = dtype
+ return dtype
def _parse_fn_end(self, fn: Function) -> None:
"""
@@ -1918,7 +1917,9 @@ def _parse_fn_end(self, fn: Function) -> None:
fn.raw_requires = self._parse_requires(rtok)
if self.lex.token_if("ARROW"):
- self._parse_trailing_return_type(fn)
+ return_type = self._parse_trailing_return_type(fn.return_type)
+ fn.has_trailing_return = True
+ fn.return_type = return_type
if self.lex.token_if("{"):
self._discard_contents("{", "}")
@@ -1966,7 +1967,9 @@ def _parse_method_end(self, method: Method) -> None:
elif tok_value in ("&", "&&"):
method.ref_qualifier = tok_value
elif tok_value == "->":
- self._parse_trailing_return_type(method)
+ return_type = self._parse_trailing_return_type(method.return_type)
+ method.has_trailing_return = True
+ method.return_type = return_type
if self.lex.token_if("{"):
self._discard_contents("{", "}")
method.has_body = True
@@ -2000,6 +2003,7 @@ def _parse_function(
is_friend: bool,
is_typedef: bool,
msvc_convention: typing.Optional[LexToken],
+ is_guide: bool = False,
) -> bool:
"""
Assumes the caller has already consumed the return type and name, this consumes the
@@ -2076,7 +2080,21 @@ def _parse_function(
self.visitor.on_method_impl(state, method)
return method.has_body or method.has_trailing_return
-
+ elif is_guide:
+ assert isinstance(state, (ExternBlockState, NamespaceBlockState))
+ if not self.lex.token_if("ARROW"):
+ raise self._parse_error(None, expected="Trailing return type")
+ return_type = self._parse_trailing_return_type(
+ Type(PQName([AutoSpecifier()]))
+ )
+ guide = DeductionGuide(
+ return_type,
+ name=pqname,
+ parameters=params,
+ doxygen=doxygen,
+ )
+ self.visitor.on_deduction_guide(state, guide)
+ return False
else:
assert return_type is not None
fn = Function(
@@ -2210,7 +2228,9 @@ def _parse_cv_ptr_or_fn(
assert not isinstance(dtype, FunctionType)
dtype = dtype_fn = FunctionType(dtype, fn_params, vararg)
if self.lex.token_if("ARROW"):
- self._parse_trailing_return_type(dtype_fn)
+ return_type = self._parse_trailing_return_type(dtype_fn.return_type)
+ dtype_fn.has_trailing_return = True
+ dtype_fn.return_type = return_type
else:
msvc_convention = None
@@ -2391,6 +2411,7 @@ def _parse_decl(
destructor = False
op = None
msvc_convention = None
+ is_guide = False
# If we have a leading (, that's either an obnoxious grouping
# paren or it's a constructor
@@ -2441,8 +2462,15 @@ def _parse_decl(
# grouping paren like "void (name(int x));"
toks = self._consume_balanced_tokens(tok)
- # .. not sure what it's grouping, so put it back?
- self.lex.return_tokens(toks[1:-1])
+ # check to see if the next token is an arrow, and thus a trailing return
+ if self.lex.token_peek_if("ARROW"):
+ self.lex.return_tokens(toks)
+ # the leading name of the class/ctor has been parsed as a type before the parens
+ pqname = parsed_type.typename
+ is_guide = True
+ else:
+ # .. not sure what it's grouping, so put it back?
+ self.lex.return_tokens(toks[1:-1])
if dtype:
msvc_convention = self.lex.token_if_val(*self._msvc_conventions)
@@ -2473,6 +2501,7 @@ def _parse_decl(
is_friend,
is_typedef,
msvc_convention,
+ is_guide,
)
elif msvc_convention:
raise self._parse_error(msvc_convention)
diff --git a/cxxheaderparser/simple.py b/cxxheaderparser/simple.py
index 2538683..02bb56e 100644
--- a/cxxheaderparser/simple.py
+++ b/cxxheaderparser/simple.py
@@ -35,6 +35,7 @@
from .types import (
ClassDecl,
Concept,
+ DeductionGuide,
EnumDecl,
Field,
ForwardDecl,
@@ -123,6 +124,9 @@ class NamespaceScope:
#: Child namespaces
namespaces: typing.Dict[str, "NamespaceScope"] = field(default_factory=dict)
+ #: Deduction guides
+ deduction_guides: typing.List[DeductionGuide] = field(default_factory=list)
+
Block = typing.Union[ClassScope, NamespaceScope]
@@ -317,6 +321,11 @@ def on_class_friend(self, state: SClassBlockState, friend: FriendDecl) -> None:
def on_class_end(self, state: SClassBlockState) -> None:
pass
+ def on_deduction_guide(
+ self, state: SNonClassBlockState, guide: DeductionGuide
+ ) -> None:
+ state.user_data.deduction_guides.append(guide)
+
def parse_string(
content: str,
diff --git a/cxxheaderparser/types.py b/cxxheaderparser/types.py
index d15b76f..1aa0b99 100644
--- a/cxxheaderparser/types.py
+++ b/cxxheaderparser/types.py
@@ -896,3 +896,21 @@ class UsingAlias:
#: Documentation if present
doxygen: typing.Optional[str] = None
+
+
+@dataclass
+class DeductionGuide:
+ """
+ .. code-block:: c++
+
+ template <class T>
+ MyClass(T) -> MyClass(int);
+ """
+
+ #: Only constructors and destructors don't have a return type
+ result_type: typing.Optional[DecoratedType]
+
+ name: PQName
+ parameters: typing.List[Parameter]
+
+ doxygen: typing.Optional[str] = None
diff --git a/cxxheaderparser/visitor.py b/cxxheaderparser/visitor.py
index df0129d..000f8d0 100644
--- a/cxxheaderparser/visitor.py
+++ b/cxxheaderparser/visitor.py
@@ -9,6 +9,7 @@
from .types import (
Concept,
+ DeductionGuide,
EnumDecl,
Field,
ForwardDecl,
@@ -236,6 +237,13 @@ def on_class_end(self, state: ClassBlockState) -> None:
``on_variable`` for each instance declared.
"""
+ def on_deduction_guide(
+ self, state: NonClassBlockState, guide: DeductionGuide
+ ) -> None:
+ """
+ Called when a deduction guide is encountered
+ """
+
class NullVisitor:
"""
@@ -318,5 +326,10 @@ def on_class_method(self, state: ClassBlockState, method: Method) -> None:
def on_class_end(self, state: ClassBlockState) -> None:
return None
+ def on_deduction_guide(
+ self, state: NonClassBlockState, guide: DeductionGuide
+ ) -> None:
+ return None
+
null_visitor = NullVisitor()
diff --git a/tests/test_template.py b/tests/test_template.py
index 344e98f..ffdf8e9 100644
--- a/tests/test_template.py
+++ b/tests/test_template.py
@@ -5,6 +5,7 @@
BaseClass,
ClassDecl,
DecltypeSpecifier,
+ DeductionGuide,
Field,
ForwardDecl,
Function,
@@ -2163,3 +2164,86 @@ def test_member_class_template_specialization() -> None:
]
)
)
+
+
+def test_template_deduction_guide() -> None:
+ content = """
+ template <class CharT, class Traits = std::char_traits<CharT>>
+ Error(std::basic_string_view<CharT, Traits>) -> Error<std::string>;
+ """
+ data = parse_string(content, cleandoc=True)
+
+ assert data == ParsedData(
+ namespace=NamespaceScope(
+ deduction_guides=[
+ DeductionGuide(
+ result_type=Type(
+ typename=PQName(
+ segments=[
+ NameSpecifier(
+ name="Error",
+ specialization=TemplateSpecialization(
+ args=[
+ TemplateArgument(
+ arg=Type(
+ typename=PQName(
+ segments=[
+ NameSpecifier(name="std"),
+ NameSpecifier(
+ name="string"
+ ),
+ ]
+ )
+ )
+ )
+ ]
+ ),
+ )
+ ]
+ )
+ ),
+ name=PQName(segments=[NameSpecifier(name="Error")]),
+ parameters=[
+ Parameter(
+ type=Type(
+ typename=PQName(
+ segments=[
+ NameSpecifier(name="std"),
+ NameSpecifier(
+ name="basic_string_view",
+ specialization=TemplateSpecialization(
+ args=[
+ TemplateArgument(
+ arg=Type(
+ typename=PQName(
+ segments=[
+ NameSpecifier(
+ name="CharT"
+ )
+ ]
+ )
+ )
+ ),
+ TemplateArgument(
+ arg=Type(
+ typename=PQName(
+ segments=[
+ NameSpecifier(
+ name="Traits"
+ )
+ ]
+ )
+ )
+ ),
+ ]
+ ),
+ ),
+ ]
+ )
+ )
+ )
+ ],
+ )
+ ]
+ )
+ )