Next_Expression_Index - Texas Instruments TI-89 Developer's Manual

Appendix A: System Routines — EStack Utilities

next_expression_index

Declaration: EStackIndex next_expression_index (EStackIndex i )
Category(ies): EStack Utilities
Description: Returns the index of the next expression deeper than the one indexed
by i .
i
Inputs:
Outputs: Index of the quantum just below (lower address) the entire expression
indexed by i .
Assumptions: None
Side Effects: Throws an ILLEGAL_TAG_ERROR, if i or one of its subexpressions does
not contain a valid tag. This indicates a malformed estack or an i that is
pointing to an END_TAG, into the middle of a number, or into the middle of
a variable name, for example.
Availability: All versions of the TI-89 / TI-92 Plus.
TI-89 / TI-92 Plus
Differences: None
See Also: None
Example:
/*********************************************************/
/* Title: remaining_element_count
/* Description: Get number of expressions in tail.
/* Input: estack index i
/* i indexes a tail of expressions terminated
/* by END_TAG.
/* Output: unsigned number of expressions in the tail
/*********************************************************/
ELEMENT_COUNT remaining_element_count (EStackIndex i) {
ELEMENT_COUNT ans = 0u;
while (ESTACK (i) != END_TAG) {
++ans;
i = next_expression_index (i);
}
return (ans);
}
TI-89 / TI-92 Plus Developer Guide
— Index of the top (highest address) tag of an expression.
Not for Distribution
*/
*/
*/
*/
*/
*/
Beta Version January 26, 2001
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