The public API of the library

Classes
class	jmespath::Expression
	The Expression class represents a JMESPath expression. More...

Functions
template<typename JsonT >
std::enable_if_t< std::is_same < std::decay_t< JsonT >, Json > ::value, Json >	jmespath::search (const Expression &expression, JsonT &&document)
	Finds or creates the results for the expression evaluated on the given document. More...

Detailed Description

---

Class Documentation

class jmespath::Expression

The Expression class represents a JMESPath expression.

The Expression class can be used to store a parsed JMESPath expression and reuse it for multiple searches.

Note

This class is reentrant.

Public Member Functions
	Expression ()
	Constructs an empty Expression object. More...
	Expression (const Expression &other)
	Constructs a copy of other. More...
	Expression (Expression &&other)
	Move-constructs an Expression by moving the value of other to this object. More...
template<typename U , typename std::enable_if< std::is_convertible< U, String >::value >::type * = nullptr>
	Expression (U &&expression)
	Constructs an Expression object by forwarding argument. More...
Expression &	operator= (const Expression &other)
	Assigns other to this expression and returns a reference to this expression. More...
Expression &	operator= (Expression &&other)
	Move-assigns other to this expression and returns a reference to this expression. More...
bool	operator== (const Expression &other) const
	Equality compares this expression to the other. More...
String	toString () const
	Converts the expression to the string representation of the JMESPath expression. More...
bool	isEmpty () const
	Checks whether this object has been initialized. expression. More...
const ast::ExpressionNode *	astRoot () const
	Returns a pointer to the root expression in the abstract syntax tree. More...
Private Member Functions
void	parseExpression (const String &expressionString)
	Parses the expressionString and updates the AST. More...
Private Attributes
String	m_expressionString
	The string representation of the JMESPath expression. More...
std::unique_ptr < ast::ExpressionNode, ExpressionDeleter >	m_astRoot
	The root node of the ast. More...

Constructor & Destructor Documentation

jmespath::Expression::Expression

(

)

Constructs an empty Expression object.

jmespath::Expression::Expression

(

const Expression &

other

)

Constructs a copy of other.

Parameters

[in]

other

The object that should be copied.

jmespath::Expression::Expression

(

Expression &&

other

)

Move-constructs an Expression by moving the value of other to this object.

Parameters

[in]

other

The object whose value should be mvoed.

template<typename U , typename std::enable_if< std::is_convertible< U, String >::value >::type * = nullptr>

jmespath::Expression::Expression ( U &&  expression )

inline

Constructs an Expression object by forwarding argument.

This constructor participates in overload resolution only if U is implicitly convertible to String. Argument should describe a valid JMESPath expression.

Parameters

[in]

argument

The value that should be forwarded.

Template Parameters

U	The type of argument.

Exceptions

SyntaxError

When the syntax of the specified expression is invalid.

Member Function Documentation

const ast::ExpressionNode * jmespath::Expression::astRoot

(

)

const

Returns a pointer to the root expression in the abstract syntax tree.

Returns

A pointer to the root expression or nullptr if the object is empty.

bool jmespath::Expression::isEmpty

(

)

const

Checks whether this object has been initialized. expression.

Returns

Returns true the expression has not been initialized yet, otherwise returns false.

Expression & jmespath::Expression::operator=

(

const Expression &

other

)

Assigns other to this expression and returns a reference to this expression.

Parameters

[in]

other

The expression that should be assigned.

Returns

Reference to this expression.

Expression & jmespath::Expression::operator=

(

Expression &&

other

)

Move-assigns other to this expression and returns a reference to this expression.

Parameters

[in]

other

The expression that should be moved.

Returns

Reference to this expression.

bool jmespath::Expression::operator==

(

const Expression &

other

)

const

Equality compares this expression to the other.

Parameters

[in]

other

The expression that should be compared.

Returns

Returns true if this object is equal to the other, otherwise false

void jmespath::Expression::parseExpression ( const String &  expressionString )

private

Parses the expressionString and updates the AST.

Parameters

[in]

expressionString

The string representation of the JMESPath expression.

Exceptions

SyntaxError

When the syntax of the specified expressionString is invalid.

String jmespath::Expression::toString

(

)

const

Converts the expression to the string representation of the JMESPath expression.

Returns

[in] String representation of the JMESPath expression.

Member Data Documentation

std::unique_ptr<ast::ExpressionNode, ExpressionDeleter> jmespath::Expression::m_astRoot

private

The root node of the ast.

String jmespath::Expression::m_expressionString

private

The string representation of the JMESPath expression.

Function Documentation

template<typename JsonT >

std::enable_if_t< std::is_same< std::decay_t< JsonT >, Json >::value, Json > jmespath::search	(	const Expression &	expression,
		JsonT &&	document
	)

Finds or creates the results for the expression evaluated on the given document.

The expression string should be encoded in UTF-8.

Parameters

expression	JMESPath expression.
document	Input JSON document

Returns

Result of the evaluation of the expression in Json format

Note

This function is reentrant. Since it takes the expression by reference the value of the expression should be protected from changes until the function returns.

Exceptions

InvalidAgrument	If a precondition fails. Usually signals an internal error.
InvalidValue	When an invalid value is specified for an expression. For example a 0 step value for a slice expression.
UnknownFunction	When an unknown JMESPath function is called in the expression.
InvalidFunctionArgumentArity	When a JMESPath function is called with an unexpected number of arguments in the expression.
InvalidFunctionArgumentType	When an invalid type of argument was specified for a JMESPath function call in the expression.