atleast.h

#ifndef LIBWCCL_OPS_FUNCTIONS_BOOL_ITERATIONS_ATLEAST_H
#define LIBWCCL_OPS_FUNCTIONS_BOOL_ITERATIONS_ATLEAST_H

#include <libwccl/ops/functions/bool/iteration.h>

namespace Wccl {

/**
 * Iterative operator "atleast", checking if there
 * is some minimum number of positions within
 * given range, that make evaluating condition return true
 */
class AtLeast : public Iteration
{
public:
	AtLeast(
		const PosFunctionPtr& left_pos_expr,
		const PosFunctionPtr& right_pos_expr,
		const VariableAccessor<Position>& iter_var_acc,
		const BoolFunctionPtr& evaluating_expr,
		int min_matches)
		: Iteration(left_pos_expr, right_pos_expr, iter_var_acc,
					evaluating_expr, false), // false==no crossing ranges
		  min_matches_(min_matches)
	{
		BOOST_ASSERT(min_matches_ > 0);
	}

	/**
	 * @returns Name of the function: "atleast".
	 */
	std::string raw_name() const {
		return "atleast";
	}

	/**
	 * @returns String reperesentation of AtLeast Operator:
	 * atleast(left_pos_expr, right_pos_expr, variable, eval_expr, min_matches)
	 */
	std::string to_string(const Corpus2::Tagset& tagset) const;

protected:
	/**
	 * @returns True, if for at least min_matches positions
	 * within range the evaluating expression returned true.
	 * False otherwise.
	 * @note Upon success, the iteration variable is
	 * set to the "min_matches"th position in range (that is the
	 * position that made the stop condition true in this case).
	 */ 
	bool iterate(
		int left,
		int right,
		Position &p,
		const FunExecContext &context) const;

	/**
	 * Writes raw string reperesentation of Iteration Operator. This is
	 * default representation of
	 * atleast(raw_left_p_expr, raw_right_p_expr, var, raw_eval_expr, min_matches)
	 * @note This version doesn't require a Tagset, but may
	 * be incomplete and/or contain internal info.
	 * @returns Stream written to.
	 */
	std::ostream& write_to(std::ostream& ostream) const;

private:
	const int min_matches_;
};


} /* end ns Wccl */

#endif // LIBWCCL_OPS_FUNCTIONS_BOOL_ITERATIONS_ATLEAST_H