SET.EVAL_VALID Function

Syntax

Result_Flag as L = Eval_Valid(C expression)

Arguments

expression: An expression that incorporates fields of the tables of the set.

Description

Returns TRUE if expression is valid in the context of the table.

Discussion

The .EVAL_VALID()evaluates Expression and returns .T. (TRUE), if Expression is valid (can be interpreted as Xbasic code), or .F. (FALSE) if the Expression is invalid. This function is useful when the expression to be evaluated is itself constructed by another expression. The <SET>.EVAL() method will return the value of the expression.

Example

dim s as P
s = set.open("invoice")
? s.eval_valid("invoice_header->data")
=  .F. ' the fieldname is spelled wrong
? s.eval_valid("invoice_header->date")
=.T.
? s.eval("invoice_header->date")
=  {01/10/2016}