An interval is either an open, closed, or semi-open contiguous subset of the real line.

The verify(expr1, expr2, interval(character)) calling sequence returns true if it can determine that the point expr1 is located in the interval defined by the second argument.

The options available for describing the character of the interval are: open..open, closed..closed, open..closed, and closed..open.  The abbreviations open and closed are equivalent to open..open and closed..closed, respectively.

This verification is a short form for calling the appropriate forms of the verifications greater_than, greater_equal, less_than, and less_equal.

This verification is not symmetric.

If expr1 is not of type algebraic or expr2 is not of type range(algebraic), then false is returned.