From 276149824e043595312c291ad1dfe4bf4b4f381b Mon Sep 17 00:00:00 2001
From: Adam Wardynski <award@.(win7-laptop)>
Date: Fri, 3 Dec 2010 21:30:29 +0100
Subject: [PATCH] ABC for Iteration Operators. The concept has been reworked a
bit.
---
libwccl/ops/functions/bool/iteration.cpp | 74 ++++++++++---------
libwccl/ops/functions/bool/iteration.h | 92 +++++++++++++++---------
2 files changed, 97 insertions(+), 69 deletions(-)
diff --git a/libwccl/ops/functions/bool/iteration.cpp b/libwccl/ops/functions/bool/iteration.cpp
index fd9c97c..86707bf 100644
--- a/libwccl/ops/functions/bool/iteration.cpp
+++ b/libwccl/ops/functions/bool/iteration.cpp
@@ -1,47 +1,57 @@
#include <libwccl/ops/functions/bool/iteration.h>
#include <libwccl/ops/functions/bool/predicate.h>
-
+#include <sstream>
namespace Wccl {
-#ifndef _MSC_VER
-const int Iteration::MatchAll;
-#endif
+std::string Iteration::to_string(const Corpus2::Tagset& tagset) const
+{
+ std::ostringstream ss;
+ ss << name(tagset) << "("
+ << left_pos_expr_->to_string(tagset) << ", "
+ << right_pos_expr_->to_string(tagset) << ", "
+ << Position::var_repr(iter_var_acc_.get_name()) << ", "
+ << evaluating_expr_->to_string(tagset) << ")";
+ return ss.str();
+}
+
+std::string Iteration::to_raw_string() const
+{
+ std::ostringstream ss;
+ ss << raw_name() << "("
+ << left_pos_expr_->to_raw_string() << ", "
+ << right_pos_expr_->to_raw_string() << ", "
+ << Position::var_repr(iter_var_acc_.get_name()) << ", "
+ << evaluating_expr_->to_raw_string() << ")";
+ return ss.str();
+}
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<const Position>& range_begin = left_pos_expr_->apply(context);
+ const boost::shared_ptr<const Position>& range_end = right_pos_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) {
+ // Get absolute values for left and right extremes of the range
+ int left = sc.get_abs_position(*range_begin);
+ int right = sc.get_abs_position(*range_end);
+ // Proceed only if range extremes are not "nowhere".
+ if (left != Position::Nowhere && right != Position::Nowhere) {
// Trim range to sentence boundaries
- if (abs_begin < 0) {
- abs_begin = 0;
+ if (left < 0) {
+ left = 0;
}
- if (abs_end >= sc.size()) {
- abs_end = sc.size() - 1;
+ if (right >= sc.size()) {
+ right = 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);
- }
+ if (left <= right) {
+ // Change range from absolute to relative and iterate
+ left -= sc.get_position();
+ right -= sc.get_position();
+ if (iterate(left, right, *iter_var, context)) {
+ return Predicate::True(context);
}
}
}
@@ -50,10 +60,4 @@ Iteration::BaseRetValPtr Iteration::apply_internal(const FunExecContext& context
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
index 1b27b9f..f5f9290 100644
--- a/libwccl/ops/functions/bool/iteration.h
+++ b/libwccl/ops/functions/bool/iteration.h
@@ -10,57 +10,81 @@ namespace Wccl {
/**
* Abstract base class for a class of operators that iterate over a range.
*/
-class Iteration : public Function<Bool> {
+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:
+ /**
+ * @returns String reperesentation of Iteration Operator. This is
+ * default representation of
+ * name(left_pos_expr, right_pos_expr, variable, eval_expr)
+ */
+ std::string to_string(const Corpus2::Tagset& tagset) const;
+
+ /**
+ * @returns String reperesentation of Iteration Operator. This is
+ * default representation of
+ * raw_name(raw_left_pos_expr, raw_right_pos_expr, variable, raw_eval_expr)
+ * @note This version doesn't require a Tagset, but may
+ * be incomplete and/or contain internal info.
+ */
+ std::string to_raw_string() const;
+protected:
+ const PosFunctionPtr& left_pos_expr_;
+ const PosFunctionPtr& right_pos_expr_;
+ const VariableAccessor<Position> iter_var_acc_;
+ const BoolFunctionPtr& evaluating_expr_;
+
Iteration(
- const PosFunctionPtr& range_begin_expr,
- const PosFunctionPtr& range_end_expr,
+ const PosFunctionPtr& left_pos_expr,
+ const PosFunctionPtr& right_pos_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),
+ const BoolFunctionPtr& evaluating_expr)
+ : left_pos_expr_(left_pos_expr),
+ right_pos_expr_(right_pos_expr),
iter_var_acc_(iter_var_acc),
- condition_expr_(condition_expr),
- match_count_(match_count),
- direction_(direction)
+ evaluating_expr_(evaluating_expr)
{
- BOOST_ASSERT(range_begin_expr_);
- BOOST_ASSERT(range_end_expr_);
- BOOST_ASSERT(condition_expr_);
- BOOST_ASSERT(match_count == MatchAll || match_count > 0);
+ BOOST_ASSERT(left_pos_expr_);
+ BOOST_ASSERT(right_pos_expr_);
+ BOOST_ASSERT(evaluating_expr_);
}
/**
- * Evaluate argument expression and assign the result to underlying variable.
- * @returns True.
+ * Gets start and end positions from arguments to create
+ * a range of positions to iterate over using a supplied
+ * iteration variable, evaluating positions within the
+ * range using supplied evaluation function.
+ * Range is trimmed to sentence boundaries.
+ * In case of an invalid range (begin and end cross over or
+ * either of them points Nowhere), False is returned and iteration
+ * variable set to Nowhere.
+ * If range is correct, return value depends on stopping condition
+ * that describes how many positions within the range have to evaluate
+ * to true. Exact details depend on type of iteration, and are
+ * specified by the subclasses via \link iterate \endlink method.
+ * If the stopping condition has been met positively,
+ * the iteration variable is set to the first position that made
+ * the condition true, and True is returned.
+ * If whole range has been iterated over without meeting the stopping
+ * condition, False is returned and iteration variable is set to
+ * Nowhere.
+ * @returns False in case of invalid range or when whole range has
+ * been iterated without meeting stop condition specified by a subclass.
+ * True is returned if the stop condition has been met.
*/
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;
+ virtual bool iterate(
+ int left,
+ int right,
+ Position &p,
+ const FunExecContext &context) const = 0;
};
-
} /* end ns Wccl */
#endif // LIBWCCL_OPS_FUNCTIONS_BOOL_ITERATION_H
--
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