From 1050b71d0614aa73f575195aafd49f3f1ff12d40 Mon Sep 17 00:00:00 2001
From: Adam Wardynski <award@.(B-4.4.46a)>
Date: Fri, 3 Dec 2010 16:41:00 +0100
Subject: [PATCH] Base class for iterations, WIP.
---
libwccl/CMakeLists.txt | 1 +
libwccl/ops/functions/bool/iteration.cpp | 59 +++++++++++++++++++++
libwccl/ops/functions/bool/iteration.h | 66 ++++++++++++++++++++++++
3 files changed, 126 insertions(+)
create mode 100644 libwccl/ops/functions/bool/iteration.cpp
create mode 100644 libwccl/ops/functions/bool/iteration.h
diff --git a/libwccl/CMakeLists.txt b/libwccl/CMakeLists.txt
index a88b82f..320dbd2 100644
--- a/libwccl/CMakeLists.txt
+++ b/libwccl/CMakeLists.txt
@@ -28,6 +28,7 @@ endif(WIN32)
SET(libwccl_STAT_SRC
exception.cpp
ops/formatters.cpp
+ ops/functions/bool/iteration.cpp
ops/functions/bool/predicate.cpp
ops/functions/bool/predicates/and.cpp
ops/functions/bool/predicates/logicalpredicate.cpp
diff --git a/libwccl/ops/functions/bool/iteration.cpp b/libwccl/ops/functions/bool/iteration.cpp
new file mode 100644
index 0000000..fd9c97c
--- /dev/null
+++ b/libwccl/ops/functions/bool/iteration.cpp
@@ -0,0 +1,59 @@
+#include <libwccl/ops/functions/bool/iteration.h>
+#include <libwccl/ops/functions/bool/predicate.h>
+
+
+namespace Wccl {
+
+#ifndef _MSC_VER
+const int Iteration::MatchAll;
+#endif
+
+Iteration::BaseRetValPtr Iteration::apply_internal(const FunExecContext& context) const
+{
+ const boost::shared_ptr<const Position>& range_begin = range_begin_expr_->apply(context);
+ const boost::shared_ptr<const Position>& range_end = range_end_expr_->apply(context);
+ const boost::shared_ptr<Position>& iter_var = context.variables()->get_fast(iter_var_acc_);
+
+ const SentenceContext& sc = context.sentence_context();
+
+ int abs_begin = sc.get_abs_position(*range_begin);
+ int abs_end = sc.get_abs_position(*range_end);
+
+ // Proceed only if range positions are not "nowhere".
+ if (abs_begin != Position::Nowhere && abs_end != Position::Nowhere) {
+ // Trim range to sentence boundaries
+ if (abs_begin < 0) {
+ abs_begin = 0;
+ }
+ if (abs_end >= sc.size()) {
+ abs_end = sc.size() - 1;
+ }
+ int range_size = abs_begin - abs_end + 1;
+ // Proceed only if range isn't empty
+ if (range_size > 0) {
+ int n = (match_count_ == MatchAll) ? range_size : match_count_;
+ // Proceed only if the range actually has enough positions to match
+ if (n <= range_size) {
+ if (direction_ == Forward) {
+ if (iterate(abs_begin, abs_end, 1, *iter_var, context)) {
+ return Predicate::True(context);
+ }
+ }
+ if (iterate(abs_end, abs_begin, -1, *iter_var, context)) {
+ return Predicate::True(context);
+ }
+ }
+ }
+ }
+ // In case of failure, set iteration variable to Nowhere and return False
+ iter_var->set_value(Position::Nowhere);
+ return Predicate::False(context);
+}
+
+bool Iteration::iterate(int start, int stop, int step, Position &p, const FunExecContext &context) const
+{
+ //TODO: implement
+ return false;
+}
+
+} /* end ns Wccl */
diff --git a/libwccl/ops/functions/bool/iteration.h b/libwccl/ops/functions/bool/iteration.h
new file mode 100644
index 0000000..1b27b9f
--- /dev/null
+++ b/libwccl/ops/functions/bool/iteration.h
@@ -0,0 +1,66 @@
+#ifndef LIBWCCL_OPS_FUNCTIONS_BOOL_ITERATION_H
+#define LIBWCCL_OPS_FUNCTIONS_BOOL_ITERATION_H
+
+#include <libwccl/ops/function.h>
+#include <libwccl/values/bool.h>
+#include <libwccl/values/position.h>
+
+namespace Wccl {
+
+/**
+ * Abstract base class for a class of operators that iterate over a range.
+ */
+class Iteration : public Function<Bool> {
+public:
+ typedef boost::shared_ptr<Function<Position> > PosFunctionPtr;
+ typedef boost::shared_ptr<Function<Bool> > BoolFunctionPtr;
+ static const int MatchAll = boost::integer_traits<int>::const_min;
+ typedef enum Direction
+ {
+ Forward,
+ Backward
+ } Direction;
+
+protected:
+
+ Iteration(
+ const PosFunctionPtr& range_begin_expr,
+ const PosFunctionPtr& range_end_expr,
+ const VariableAccessor<Position>& iter_var_acc,
+ const BoolFunctionPtr& condition_expr,
+ int match_count = MatchAll,
+ Direction direction = Forward)
+ : range_begin_expr_(range_begin_expr),
+ range_end_expr_(range_end_expr),
+ iter_var_acc_(iter_var_acc),
+ condition_expr_(condition_expr),
+ match_count_(match_count),
+ direction_(direction)
+ {
+ BOOST_ASSERT(range_begin_expr_);
+ BOOST_ASSERT(range_end_expr_);
+ BOOST_ASSERT(condition_expr_);
+ BOOST_ASSERT(match_count == MatchAll || match_count > 0);
+ }
+
+ /**
+ * Evaluate argument expression and assign the result to underlying variable.
+ * @returns True.
+ */
+ BaseRetValPtr apply_internal(const FunExecContext& context) const;
+
+ const PosFunctionPtr& range_begin_expr_;
+ const PosFunctionPtr& range_end_expr_;
+ const VariableAccessor<Position> iter_var_acc_;
+ const BoolFunctionPtr& condition_expr_;
+ const int match_count_;
+ const Direction direction_;
+
+private:
+ bool iterate(int start, int stop, int step, Position& p, const FunExecContext& context) const;
+};
+
+
+} /* end ns Wccl */
+
+#endif // LIBWCCL_OPS_FUNCTIONS_BOOL_ITERATION_H
--
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