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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#pragma once
#include <cmath>
#include <memory>
#include <vespa/vespalib/stllike/string.h>
#include <vespa/vespalib/util/stringfmt.h>
#include <map>
#include "basic_nodes.h"
#include "delete_node.h"
#include "value.h"
namespace vespalib {
namespace eval {
enum class PassParams : uint8_t { SEPARATE, ARRAY, LAZY };
/**
* Interface used to perform custom symbol extraction. This is
* typically used by the ranking framework to extend what will be
* parsed as parameter names.
**/
struct SymbolExtractor {
virtual void extract_symbol(const char *pos_in, const char *end_in,
const char *&pos_out, vespalib::string &symbol_out) const = 0;
virtual ~SymbolExtractor() {}
};
struct NodeVisitor;
/**
* When you parse an expression you get a Function. It contains the
* AST root and the names of all parameters. A function can only be
* evaluated using the appropriate number of parameters.
**/
class Function : public std::enable_shared_from_this<Function>
{
private:
nodes::Node_UP _root;
std::vector<vespalib::string> _params;
struct ctor_tag {};
public:
Function(nodes::Node_UP root_in, std::vector<vespalib::string> params_in, ctor_tag) noexcept
: _root(std::move(root_in)), _params(std::move(params_in)) {}
Function(Function &&rhs) = delete;
Function(const Function &rhs) = delete;
Function &operator=(Function &&rhs) = delete;
Function &operator=(const Function &rhs) = delete;
~Function() { delete_node(std::move(_root)); }
size_t num_params() const { return _params.size(); }
vespalib::stringref param_name(size_t idx) const { return _params[idx]; }
bool has_error() const;
vespalib::string get_error() const;
const nodes::Node &root() const { return *_root; }
static std::shared_ptr<Function const> create(nodes::Node_UP root_in, std::vector<vespalib::string> params_in);
static std::shared_ptr<Function const> parse(vespalib::stringref expression);
static std::shared_ptr<Function const> parse(vespalib::stringref expression, const SymbolExtractor &symbol_extractor);
static std::shared_ptr<Function const> parse(const std::vector<vespalib::string> ¶ms, vespalib::stringref expression);
static std::shared_ptr<Function const> parse(const std::vector<vespalib::string> ¶ms, vespalib::stringref expression,
const SymbolExtractor &symbol_extractor);
vespalib::string dump() const {
nodes::DumpContext dump_context(_params);
return _root->dump(dump_context);
}
vespalib::string dump_as_lambda() const;
// Utility function used to unwrap an expression contained inside
// a named wrapper. For example 'max(x+y)' -> 'max', 'x+y'
static bool unwrap(vespalib::stringref input,
vespalib::string &wrapper,
vespalib::string &body,
vespalib::string &error);
/**
* Issues is used to report issues relating to the function
* structure, typically to explain why a function cannot be
* evaluated in a specific context due to it using features not
* supported in that context.
**/
struct Issues {
std::vector<vespalib::string> list;
operator bool() const { return !list.empty(); }
Issues(std::vector<vespalib::string> &&list_in) : list(std::move(list_in)) {}
};
};
} // namespace vespalib::eval
} // namespace vespalib
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