Solvers and expressions

Configure expression evaluation and operator precedence.

enum snt::exs::TokenType

List of operator types

Values:

enumerator EMPTY_TOKEN

Token is empty.

enumerator OPERATOR_TOKEN

Token is an operator.

enumerator ATOM_TOKEN

Token is an atom.

enum snt::exs::OperationType

Type of an operation

Values:

enumerator UNARY_OPERATION

Unary operation operates on the atom value.

enumerator BINARY_OPERATION

Binary operation operates between two atoms.

enumerator TERNARY_OPERATION

Ternary operation operates with three atoms.

enumerator GROUP_OPERATION

Group operation operates on various number of atoms.

enum snt::exs::OperatorType

List of all operators

Values:

enumerator NONE_OPERATOR

Item is not an operator.

enumerator ADD_OPERATOR

Addition of values.

enumerator SUBTRACT_OPERATOR

Subtraction of values.

enumerator MULTIPLY_OPERATOR

Multiplication of values.

enumerator DIVIDE_OPERATOR

Division of values.

enumerator POWER_OPERATOR

Power of a value.

enumerator MODULO_OPERATOR

Modulo of values.

enumerator NOT_OPERATOR

Logical negation.

enumerator AND_OPERATOR

Logical and.

enumerator OR_OPERATOR

Logical or.

enumerator EQUAL_OPERATOR

Logical equality.

enumerator NOT_EQUAL_OPERATOR

Logical difference.

enumerator LESS_EQUAL_OPERATOR

Logical less or equal.

enumerator GREATER_EQUAL_OPERATOR

Logical greater or equal.

enumerator LESS_OPERATOR

Logical less.

enumerator GREATER_OPERATOR

Logical greater.

enumerator CONDITION_OPERATOR

Conditional operator.

enumerator PARENTHESES_OPERATOR

Parentheses.

enumerator EXPONENT_OPERATOR

Exponents.

enumerator LOGARITHM_OPERATOR

Logarithm.

enumerator LOGARITHM_10_OPERATOR

Logarithm with a base 10.

enumerator LOGARITHM_BASE_OPERATOR

Logarithm with an arbitrary base.

enumerator POWER_BASE_OPERATOR

Power with an arbitrary base.

enumerator SQUARE_ROOT_OPERATOR

Square root.

enumerator CUBIC_ROOT_OPERATOR

Cubic root.

enumerator SINUS_OPERATOR

Sinus.

enumerator COSINUS_OPERATOR

Cosinus.

enumerator TANGENS_OPERATOR

Tangens.

enumerator NUM_OPERATOR_TYPES

Total number of operators.

using snt::exs::StepListType = std::vector<std::pair<OperationType, std::vector<int>>>

static std::string snt::exs::trim(const std::string &str, const std::string &whitespace = " \t")

Remove leading and trailing spaces from a string

Parameters:

• str – String that should be trimmed

• whitespace – String with whitespace characters that will be removed

struct BaseSettings

#include <settings.h>

Base structure for expression solver settings

Subclassed by snt::dip::LogicalSettings, snt::dip::NumericalSettings

class Exception : public snt::core::Exception

#include <exceptions.h>

Subclassed by snt::exs::MissingException, snt::exs::ParserException

Public Functions

inline explicit Exception(core::ExceptionInfo info)

inline explicit Exception(std::string message, std::string details, std::string suggestion, std::string origin_file, size_t origin_line)

class Expression

#include <expression.h>

Parsed expression with an ordered list of executable steps.

Public Functions

Expression(const std::string &expression)

void shift(int nchar = 1)

void remove(const std::string &string)

std::string pop_left()

std::string to_string()

void print()

Public Members

std::string left

std::string right

std::string expr

class MissingException : public snt::exs::Exception

#include <exceptions.h>

Missing exception is triggered when functionality is not implemented yet

Public Functions

inline MissingException(std::string message, std::string file, std::size_t line)

class ParserException : public snt::exs::Exception

#include <exceptions.h>

Parser exceptions are triggered by problems during expression parsing

template<class ATOM, class SETTINGS = BaseSettings>
class Solver

#include <solver.h>

Main expression solver class

Note that internal solver and operator routines use static_cast to convert between AtomGrand and actual ATOM type. Although it may seem dangerous, within a particular solver we need to guarantee that AtomGrand will have only one derived type.

Template Parameters:

• ATOM – Atom type

• SETTINGS – Atom settings

Public Functions

inline Solver(const SETTINGS &set = {})

Default solver constructor

Parameters:

set – Solver settings

inline Solver(const OperatorList &o, const SETTINGS &set = {})

Solver constructor with modified operators

Parameters:

• o – List of operators

• set – Solver settings

inline Solver(const StepList &s, const SETTINGS &set = {})

Solver constructor with modified operator steps

Parameters:

• s – List of operator steps

• set – Solver settings

inline Solver(const OperatorList &o, const StepList &s, const SETTINGS &set = {})

Custom solver constructor

Parameters:

• o – List of operators

• s – List of operator steps

• set – Solver settings

inline void set_settings(const SETTINGS &set = {})

Set solver settings

Parameters:

set – New structure with settings

inline ATOM eval(std::string expression)

Main solver routine

Parameters:

expression – Expression that should be solved

Returns:

Final atom object with a solution

Public Members

SETTINGS settings

Setting structure.

OperatorList operators

List of used operators.

StepList steps

List of operator steps.

class StepList

#include <step_list.h>

Ordered execution steps generated from an EXS expression.

Public Functions

void append(OperationType t, const std::vector<int> &s)

Append one execution step.

Parameters:

• t – Operation category to execute.

• s – Operator identifiers executed for this step.

Public Members

StepListType steps