Is1 - Texas Instruments TI-89 Developer's Manual

Appendix A: System Routines — EStack Arithmetic

is1

Declaration: Boolean is1 (IndexConstQuantum i )
Category(ies): EStack Arithmetic
Description: Determines whether i indexes a tagged big integer 1 or tagged float 1.
Inputs: i
Outputs: Returns TRUE if i indexes a tagged big integer 1 or tagged float 1.
Otherwise, returns FALSE.
i points to the top tag of an expression.
Assumptions:
Side Effects: None
On AMS 1.05 and higher.
Availability:
TI-89 / TI-92 Plus
Differences: None
See Also: is0, is_minus1
Example:
EStackIndex index_nonnegative_factor (EStackIndex i)
/* i indexes a term.
Returns NULL_INDEX if it cannot determine that one of its explicit syntactic
factors is nonnegative.
Otherwise returns i or the index of its 1st remaining factors for which
the lead factor has been determined to be nonnegative.
*/
{ while (! is1 (i))
if (is_nonnegative (lead_factor_index (i)))
return i;
else
i = remaining_factors_index (i);
return NULL_INDEX;
}
TI-89 / TI-92 Plus Developer Guide
— Indexes an expression.
Not for Distribution
485
Beta Version January 26, 2001