Lead_Disjunct_Term_Index - Texas Instruments TI-89 Developer's Manual

Appendix A: System Routines — Logic

lead_disjunct_term_index

Declaration: EStackIndex lead_disjunct_term_index (EStackIndex i )
Category(ies): Logic
Description: Determines the lead disjunct term of the expression indexed by i .
Internally-simplified disjuncts have the most main Boolean term shallowest,
with less main terms deeper. Also, the lead Boolean term of an
internally-simplified disjunct is never a disjunct.
Inputs: i
Outputs: If i indexes an OR_TAG, returns the index of the operand just below it.
Otherwise returns i .
Assumptions: None
Side Effects: None
Availability: On AMS 2.02 and higher.
TI-89 / TI-92 Plus
Differences: None
See Also: remaining_conjuncts_index, lead_conjunct_factor_index,
remaining_disjuncts_index
Example: If i indexes the internally-simplified expression
(b or a) or c
then lead_disjunct_term_index(i) returns index(a).
If i indexes the internally-simplified expression
x > 3
then lead_disjunct_term_index(i) returns index(x > 3).
void push_but_disjunct_term (EStackIndex i, EStackIndex j)
/* i indexes a (perhaps degenerate) disjunct and j == i or j indexes one of its
remaining terms.
Pushes onto the estack the disjunct without the lead term of j.
*/
{ if (i == j)
push_expression (remaining_disjuncts_index (i));
else
{
push_but_disjunct_term (remaining_disjuncts_index (i), j);
and_onto_top (lead_disjunct_term_index (i));
}
}
TI-89 / TI-92 Plus Developer Guide
— Index of the top tag of an internally-simplified Boolean expression.
Not for Distribution
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Beta Version January 26, 2001