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/*
* Copyright (c) 2003-2023, John Wiegley. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* - Neither the name of New Artisans LLC nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* @addtogroup expr
*/
/**
* @file exprbase.h
* @author John Wiegley
*
* @ingroup expr
*
* This class provides basic behavior for all the domain specific expression
* languages used in Leger:
*
* | Typename | Description | result_type | Derives |
* |-------------+----------------------------+-----------------+-------------|
* | expr_t | Value expressions | value_t | |
* | predicate_t | Special form of expr_t | bool | expr_t |
* | query_t | Report queries | bool | predicate_t |
* | period_t | Time periods and durations | date_interval_t | |
* | draft_t | Partially filled xacts | xact_t * | |
* | format_t | Format strings | string | |
*/
#pragma once
#include "utils.h"
#include "amount.h"
namespace ledger {
DECLARE_EXCEPTION(parse_error, std::runtime_error);
DECLARE_EXCEPTION(compile_error, std::runtime_error);
DECLARE_EXCEPTION(calc_error, std::runtime_error);
DECLARE_EXCEPTION(usage_error, std::runtime_error);
class scope_t;
class call_scope_t;
template <typename ResultType>
class expr_base_t
{
public:
typedef ResultType result_type;
typedef function<result_type (call_scope_t&)> func_t;
protected:
scope_t * context;
string str;
bool compiled;
virtual result_type real_calc(scope_t& scope) = 0;
public:
expr_base_t(const expr_base_t& other)
: context(other.context), str(other.str), compiled(false) {
TRACE_CTOR(expr_base_t, "copy");
}
expr_base_t(scope_t * _context = NULL)
: context(_context), compiled(false)
{
TRACE_CTOR(expr_base_t, "scope_t *");
}
virtual ~expr_base_t() {
TRACE_DTOR(expr_base_t);
}
expr_base_t& operator=(const expr_base_t& _expr) {
if (this != &_expr) {
str = _expr.str;
context = _expr.context;
compiled = _expr.compiled;
}
return *this;
}
expr_base_t& operator=(const string& _expr) {
parse(_expr);
return *this;
}
virtual operator bool() const throw() {
return ! str.empty();
}
virtual string text() const throw() {
return str;
}
void set_text(const string& txt) {
str = txt;
compiled = false;
}
void parse(const string& expr_str,
const parse_flags_t& flags = PARSE_DEFAULT) {
std::istringstream stream(expr_str);
return parse(stream, flags, expr_str);
}
virtual void parse(std::istream&,
const parse_flags_t& = PARSE_DEFAULT,
const optional<string>& original_string = none) {
set_text(original_string ? *original_string : "<stream>");
}
virtual void mark_uncompiled() {
compiled = false;
}
void recompile(scope_t& scope) {
compiled = false;
compile(scope);
}
virtual void compile(scope_t& scope) {
if (! compiled) {
// Derived classes need to do something here.
context = &scope;
compiled = true;
}
}
result_type operator()(scope_t& scope) {
return calc(scope);
}
result_type calc(scope_t& scope)
{
if (! compiled) {
#if DEBUG_ON
if (SHOW_DEBUG("expr.compile")) {
DEBUG("expr.compile", "Before compilation:");
dump(*_log_stream);
}
#endif // DEBUG_ON
DEBUG("expr.compile", "Compiling: " << str);
compile(scope);
#if DEBUG_ON
if (SHOW_DEBUG("expr.compile")) {
DEBUG("expr.compile", "After compilation:");
dump(*_log_stream);
}
#endif // DEBUG_ON
}
DEBUG("expr.calc", "Calculating: " << str);
return real_calc(scope);
}
result_type calc() {
assert(context);
return calc(*context);
}
scope_t * get_context() {
return context;
}
void set_context(scope_t * scope) {
context = scope;
}
virtual string context_to_str() const {
return empty_string;
}
string print_to_str() const {
std::ostringstream out;
print(out);
return out.str();
}
string dump_to_str() const {
std::ostringstream out;
dump(out);
return out.str();
}
string preview_to_str(scope_t&) const {
std::ostringstream out;
preview(out);
return out.str();
}
virtual void print(std::ostream&) const {}
virtual void dump(std::ostream&) const {}
result_type preview(std::ostream& out, scope_t& scope) const {
out << _("--- Input expression ---") << std::endl;
out << text() << std::endl;
out << std::endl << _("--- Text as parsed ---") << std::endl;
print(out);
out << std::endl;
out << std::endl << _("--- Expression tree ---") << std::endl;
dump(out);
out << std::endl << _("--- Compiled tree ---") << std::endl;
compile(scope);
dump(out);
out << std::endl << _("--- Result value ---") << std::endl;
return calc();
}
};
template <typename ResultType>
std::ostream& operator<<(std::ostream& out,
const expr_base_t<ResultType>& expr) {
expr.print(out);
return out;
}
} // namespace ledger
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