EXPRESSION()

PURPOSE

Evaluate a Recital expression

SYNONYM

api_expression()

SYNOPSIS

#include "dbapi.h"
 
int	EXPRESSION(result, exp)
 
<input parameters>
char	*exp;			/* Address of a buffer containing a valid Recital command	*/
 
<output parameters>
API_EXPRESSION result;		/* Expression result							*/

DESCRIPTION

The FUNCTION() function evaluates the specified Recital expression and returns the result. This function returns 0 if successful, otherwise a Recital error number.

The API Expression result structure is defined as follows:

struct API_EXPRESSION{
    int			errno;		/* RECITAL error() number		*/
    char			type;			/* data type of result			*/
    int			width;		/* width of result				*/
    int			decimal;		/* decimal places				*/
    char			*character;		/* CHARACTER result			*/
    double		number;		/* NUMERIC result				*/
    char			logical;		/* LOGICAL result				*/
    unsigned long	date;			/* Recital DATE result			*/
    DATETIME		datetime;		/* Recital DATETIME result		*/
    CURRENCY	currency;		/* Recital CURRENCY result		*/
};

The data type result will be any one of the following:

RETURN VALUE	DESCRIPTION
C	character or memo data type
N	numeric data type
D	date data type
L	logical data type
T	datetime data type
Y	currency data type

EXAMPLE

The following example evaluates the specified expression and returns the result.

Example Recital program:

use accounts
m_result=evaluate("ord_value - paid_value")
return

Example 'C' function:

#include "dbapi.h"
 
dbapi_evaluate()
{
	struct	API_EXPRESSION result;
 
	if (_parinfo(1) == API_CTYPE) {
		EXPRESSION(&result, _parc(1));
 
		if (result.errno != 0) {
			_retni(-1);
		} else {
			_retnd(result.number);
		}
	} else {
		_retni(-1);
	}
}

SEE ALSO

COMMAND()