From: eric_at_[hidden]
Date: 2007-11-27 18:11:15
Author: eric_niebler
Date: 2007-11-27 18:11:15 EST (Tue, 27 Nov 2007)
New Revision: 41425
URL: http://svn.boost.org/trac/boost/changeset/41425
Log:
handle non-greedy repeats
Text files modified:
branches/proto/v3/boost/xpressive/detail/static/grammar2.hpp | 115 +++++++++++++++++++++++++--------------
1 files changed, 72 insertions(+), 43 deletions(-)
Modified: branches/proto/v3/boost/xpressive/detail/static/grammar2.hpp
==============================================================================
--- branches/proto/v3/boost/xpressive/detail/static/grammar2.hpp (original)
+++ branches/proto/v3/boost/xpressive/detail/static/grammar2.hpp 2007-11-27 18:11:15 EST (Tue, 27 Nov 2007)
@@ -139,6 +139,16 @@
using namespace transform;
using namespace xpressive::detail;
+ template<typename Tag>
+ struct is_generic_quant_tag
+ : mpl::false_
+ {};
+
+ template<uint_t Min, uint_t Max>
+ struct is_generic_quant_tag<generic_quant_tag<Min,Max> >
+ : mpl::true_
+ {};
+
struct as_matcher : function_transform
{
template<typename Sig>
@@ -195,6 +205,7 @@
typedef functional::make_expr<tag::terminal> _make_terminal;
typedef functional::make_expr<tag::assign> _make_assign;
typedef functional::make_expr<tag::logical_not> _make_logical_not;
+ typedef functional::make_expr<tag::negate> _make_negate;
template<typename Visitor>
struct traits_type
@@ -244,6 +255,18 @@
template<typename Char, typename Gram>
struct Cases
{
+ // Some simple grammars...
+ struct MarkedSubExpr
+ : assign<terminal<mark_placeholder>, _>
+ {};
+
+ struct GenericQuant
+ : and_<
+ if_<is_generic_quant_tag<tag_of<_> >()>
+ , unary_expr<_, Gram>
+ >
+ {};
+
// Here are some transforms ...
struct as_independent
: apply_<Gram, _make_shift_right(_, true_matcher()), no_next()>
@@ -274,10 +297,6 @@
>
{};
- struct MarkedSubExpr
- : assign<terminal<mark_placeholder>, _>
- {};
-
struct add_hidden_mark
: if_<
matches<_, MarkedSubExpr>()
@@ -286,7 +305,7 @@
>
{};
- template<typename Tag>
+ template<typename Greedy, typename Tag>
struct as_repeater
: apply_<
_
@@ -294,43 +313,50 @@
repeat_begin_matcher(mark_number(_arg(_left)))
, _make_shift_right(
_right
- , repeat_end_matcher<greedy_t>(
+ , repeat_end_matcher<Greedy>(
mark_number(_arg(_left))
// BUGBUG work around gcc bug
- //, min_type<Tag>()
- //, max_type<Tag>()
- , always<min_type<Tag> >
- , always<max_type<Tag> >
+ , always<min_type<Tag> > //, min_type<Tag>()
+ , always<max_type<Tag> > //, max_type<Tag>()
)
)
)
>
{};
- template<typename Tag, uint_t = min_type<Tag>::value, uint_t = max_type<Tag>::value>
+ template<typename Greedy, typename Tag, uint_t = min_type<Tag>::value, uint_t = max_type<Tag>::value>
struct as_default_repeat_impl
- : apply_<as_repeater<Tag>, as_marker(add_hidden_mark(_arg))>
+ : apply_<as_repeater<Greedy, Tag>, as_marker(add_hidden_mark(_arg))>
{};
- template<typename Tag, uint_t Max>
- struct as_default_repeat_impl<Tag, 0, Max>
- : apply_<_, _make_logical_not(as_default_repeat_impl<generic_quant_tag<1, Max> >)>
+ template<typename Greedy, typename Tag, uint_t Max>
+ struct as_default_repeat_impl<Greedy, Tag, 0, Max>
+ : if_<
+ Greedy()
+ , _make_negate(_make_logical_not(as_default_repeat_impl<Greedy, generic_quant_tag<1, Max> >))
+ , _make_logical_not(as_default_repeat_impl<Greedy, generic_quant_tag<1, Max> >)
+ >
{};
- template<typename Tag>
- struct as_default_repeat_impl<Tag, 0, 1>
- : apply_<_, _make_logical_not(_arg)>
+ template<typename Greedy, typename Tag>
+ struct as_default_repeat_impl<Greedy, Tag, 0, 1>
+ : if_<
+ Greedy()
+ , _make_negate(_make_logical_not(_arg))
+ , _make_logical_not(_arg)
+ >
{};
- template<typename Tag>
+ template<typename Greedy, typename Tag>
struct as_default_repeat
- : as_default_repeat_impl<Tag>
+ : as_default_repeat_impl<Greedy, Tag>
{};
+ template<typename Greedy>
struct as_simple_repeat
: apply_<
_
- , simple_repeat_matcher<as_independent(_arg), greedy_t>(
+ , simple_repeat_matcher<as_independent(_arg), Greedy>(
as_independent(_arg)
, min_type<tag_of<_> >()
, max_type<tag_of<_> >()
@@ -339,11 +365,21 @@
>
{};
+ template<typename Greedy>
struct as_repeat
: if_<
use_simple_repeat<_arg, Char>()
- , as_simple_repeat
- , Gram(as_default_repeat<tag_of<_> >(_))
+ , as_simple_repeat<Greedy>
+ , Gram(as_default_repeat<Greedy, tag_of<_> >(_))
+ >
+ {};
+
+ template<typename Greedy>
+ struct as_optional
+ : if_<
+ matches<_, MarkedSubExpr>()
+ , optional_mark_matcher<as_alternate, Greedy>(as_alternate, mark_number(_arg(_left)))
+ , optional_matcher<as_alternate, Greedy>(as_alternate)
>
{};
@@ -376,45 +412,38 @@
template<typename Dummy>
struct case_<tag::dereference, Dummy>
- : when<dereference<Gram>, as_repeat>
+ : when<dereference<Gram>, as_repeat<greedy_t> >
{};
template<typename Dummy>
struct case_<tag::posit, Dummy>
- : when<posit<Gram>, as_repeat>
+ : when<posit<Gram>, as_repeat<greedy_t> >
{};
template<uint_t Min, uint_t Max, typename Dummy>
struct case_<generic_quant_tag<Min, Max>, Dummy>
- : when<unary_expr<generic_quant_tag<Min, Max>, Gram>, as_repeat>
+ : when<unary_expr<generic_quant_tag<Min, Max>, Gram>, as_repeat<greedy_t> >
{};
template<typename Dummy>
struct case_<tag::logical_not, Dummy>
+ : when<logical_not<Gram>, as_optional<greedy_t>(_arg)>
+ {};
+
+ template<typename Dummy>
+ struct case_<tag::negate, Dummy>
: or_<
- when<
- logical_not<assign<terminal<mark_placeholder>, Gram> >
- , optional_mark_matcher<as_alternate(_arg), greedy_t>(
- as_alternate(_arg), mark_number(_arg(_left(_arg)))
- )
- >
- , when<
- logical_not<Gram>
- , optional_matcher<as_alternate(_arg), greedy_t>(
- as_alternate(_arg)
- )
- >
+ when<negate<dereference<Gram> > , as_repeat<non_greedy_t>(_arg)>
+ , when<negate<posit<Gram> > , as_repeat<non_greedy_t>(_arg)>
+ , when<negate<GenericQuant> , as_repeat<non_greedy_t>(_arg)>
+ , when<negate<logical_not<Gram> > , as_optional<non_greedy_t>(_arg(_arg))>
>
{};
template<typename Dummy>
struct case_<tag::assign, Dummy>
- : when<
- assign<terminal<mark_placeholder>, Gram>
- , Gram(as_marker)
- >
+ : when<assign<terminal<mark_placeholder>, Gram>, Gram(as_marker)>
{};
-
};
} // namespace detail