List Commands Library for 50g

[DavidM]

(The most recent version of the ListExt library is available at hpcalc.org)

Pier4r recently started a thread containing a variety of challenges designed to encourage the use of lists for solving problems in calculator programs. Working on those challenges gave me some ideas for a set of new RPL commands that would augment the built-in list processing features of the 50g, and I soon found that I had enough to start building a library for more generalized use.

In an effort to avoid hijacking Pier's thread, I thought it might be best to have a separate one to discuss the implementation of some of the commands (it's a "work in progress", and not quite ready for the General Software Library). Note that while there is a small amount of overlap with the GoferList library, this one is intended to complement it as opposed to replacing it.

It is my hope that anyone interested in list processing on the 50g will be able to make use of this, and will offer suggestions for improvements and new ideas for commands that would be useful.

For more background on some of the commands, including some comparisons with GoferList and performance benchmarks, see the following posts:

First post
Performance and GoferList comparisons
A thread pertaining to the implementation of LSHF, the "shuffling" command

Edit 2017-09-10: From this point forward I'll edit this first post with the latest version to make it easier to find.

Edit 2018-09-17: 1.2.1 release.

ListExt Release Notes

Version 1.2.1
2018-08-17

- LDDUP bug fixed: sublists weren't handled properly as of the last update.
- LDDUP adjusted to better balance performance in cases where lists have mostly duplicates.
- LPICK replaced with a faster version, especially for smaller lists.


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COMMAND SUMMARY

List Creation (CREAT menu)
LSEQ - creates a list of <count> integers as a sequence from 1..<count>
LSEQR - creates a list of integers for the range specified
LASEQ - creates a numeric sequence by repetitive addition of a constant
LMSEQ - creates a numeric sequence by repetitive multiplication by a constant
LDSEQ - creates a numeric sequence by repetitive division by a constant
LMRPT - repeats list contents as indicated by count

List Editing (EDIT menu)
LDDUP - removes duplicates from a list
LPOP - retrieves the first element in a list while leaving the rest on the stack
LPOPR - retrieves the last element in a list while leaving the rest on the stack
LPUSH - adds object to front of list
LPSHR - adds object to end of list
LPICK - returns a list containing identified elements in specified order

LREPL - replaces list elements with a substitute object as indicated
LINSR - inserts 1 or more elements into a list as indicated
LRMOV - removes 1 or more elements from a list as indicated
LFRST - returns the first <n> elements of a list
LLAST - returns the last <n> elements of a list
LRCL - recalls objects identified by variables in a list

Element Arrangement (ARRNG menu)
LROLL - rolls the list (equivalent to 1 LROT)
LRLLD - "roll down" the list (equivalent to -1 LROT)
LROT - rotates list elements left or right as indicated by count
LSWAP - swaps the positions of two list elements
LSSR - reverses the order of a sub-sequence within a list
LSHUF - shuffles the contents of a list

KSORT - Sorts a list based on keys from a separate list
REV - Reverses the individual elements of a list, string, or number

Element Grouping (GROUP menu)
LCLLT - collates a list of sublists
LDIST - distributes list items into sublists (reciprocal of LCLLT)
LGRP - replaces repeated elements with a single instance
LRPCT - list with LGRP elements and another list of the count of each element
LRPC→ - restores a list that was grouped with LRPCT
LSDIV - subdivides a list into <count> sublists

SPLIT - splits a list, string, or number as indicated into two parts
RSPLT - splits a list, string, or number as indicated from the right into two parts
LXIL - explodes inner sublists into individual elements (non-recursive)
LXILR - recursive version of LXIL
SLST→ - LIST→ that avoids Garbage Collection issues for large lists

List Testing (TEST menu)
LCNT - counts objects in a list
LEQ - checks list items to see if any do not match
MPOS - returns a list of all positions of an object in a list, or a substring in a string
MPOSL - returns a list of all positions of an object in a list or its sublists
LNRML - substitutes ROM opcodes in a list for numeric natural numbers in the range -9..9
LSAME - Executes LNRML on two lists then SAME

Combinatorics (COMB menu)
DOCOMB - feeds indicated combinations of a list to a user-supplied program
DOPERM - feeds indicated permutations of a list to a user-supplied program

List Math (LMATH menu)
LSUM - ΣLIST that also accepts lists with 0 or 1 element
LPROD - ΠLIST that also accepts lists with 0 or 1 element
LMAX - returns the maximum value contained in a list
LMIN - returns the minimum value contained in a list

String/Number Conversion (STRNG menu)
CHR+ - adds an offset to the CHR value of each character of a string
LCASE - converts upper case characters in a string to lower case
UCASE - converts lower case characters in a string to upper case
RPTCHR - creates a string of repeated characters
I→NL - converts an integer to a list of numbers
NL→I - converts a list of numbers to an integer

S→NL - converts a string to a list of numbers
NL→S - converts a list of character numbers to a string
S→SL - converts a string to a list of characters
SL→S - converts a list of characters to a string
I→BL - converts an integer into a list of remainders after repeated division by constant
BL→I - converts a list of remainders from base conversion into an exact integer

Stack Operations (STACK menu)
NMDUP - replicates a group of stack levels as indicated
NMROT - rotates stack items as indicated
SWPXY - swaps the indicated stack levels
DRPXY - drops the stack levels indicated in the range from X to Y
REVN - reverses the order of N stack levels
REVXY - reverses the order of stack levels X through Y

About1423 - Library short description and version information
Unins1423 - Detaches and deletes the ListExt library

Not included in the menu:
MENU1423 - activates the ListExt menu