Texas Instruments TI-89 Developer's Guide

250
Appendix A: System Routines — Algebra Utilities
TI
-
89 / TI
-
92 Plus Developer Guide
Not for Distribution
Beta Version January 26, 2001
is_free_of_tag
Declaration:
Boolean
is_free_of_tag
(EStackIndex
i
, Quantum
q
)
Category(ies):
Algebra Utilities
Description:
Determines whether the expression indexed by
i
contains tag
q
.
Inputs:
i
— Index of the top tag of an expression.
q
— A primary tag.
Outputs:
Returns TRUE if the expression indexed by
i
does not contain tag
q
.
Otherwise returns FALSE.
Assumptions:
None
Side Effects:
None
Availability:
All versions of the TI
-
89 / TI
-
92 Plus.
TI
-
89 / TI
-
92 Plus
Differences:
None
See Also: is_independent_of, is_independent_of_tail, is_tail_independent_of
Example:
/*
** Title: push_radians
** Description: Pushes the result of converting the specified value
** (interpreted as radians) to the currently selected measure.
** Input: estack index i of the radian value
** Output: Pushes the value converted to the currently selected measure.
*/
void push_radians (EStackIndex i)
{ if (! is_free_of_tag (i, IM_RE_TAG))
ER_THROW (ER_DOMAIN);
if (IS_RADIANS)
push_expression (i);
else
{ push_pi_on_quantum (180);
push_ratio (i, top_estack);
delete_expression (next_expression_index (top_estack));
}
}

Texas Instruments TI-89 Specifications

General

Display size (HxV)	100 x 160 mm
Memory type	639K FLASH ROM, 188K bytes RAM
Compatible operating systems	Operating System 2.09
Battery type	AAA