teca_parser Namespace Reference

Codes dealing with expression parsing. More...

Classes
class	tokenizer

Functions
template<typename tokenizer_t = teca_parser::tokenizer>
char *	infix_to_postfix (const char *iexpr, std::set< std::string > *variables)
template<typename work_t , typename arg_t , typename operand_resolver_t , typename operator_resolver_t , typename tokenizer_t = teca_parser::tokenizer>
int	eval_postfix (arg_t &iexpr_result, const char *iexpr, operand_resolver_t &operands)

Detailed Description

Codes dealing with expression parsing.

Function Documentation

eval_postfix()

template<typename work_t , typename arg_t , typename operand_resolver_t , typename operator_resolver_t , typename tokenizer_t = teca_parser::tokenizer>

int teca_parser::eval_postfix	(	arg_t &	iexpr_result,
		const char *	iexpr,
		operand_resolver_t &	operands
	)

evaluate a postfix expression. returns non zero if an error occurred. the result of the evaluated expression is returned in iexpr_result.

template types define the intermediate types used in the calculation. arg_t would likely be the const form of work_t. resolvers for constants, variables, and operators are passed. The purpose of the resolvers is to identify token class and implement variable lookup, and operator evaluation.

infix_to_postfix()

template<typename tokenizer_t = teca_parser::tokenizer>

char* teca_parser::infix_to_postfix	(	const char *	iexpr,
		std::set< std::string > *	variables
	)

Convert infix expression to postfix. returns the postfix form of the expression in a string allocated with malloc. caller to free the string. return nullptr if there is an error.

template types implement detection of classes of syntactical tokens. groups, constants, variables, and operators.