What is meaning of class RexxDictionary in NetRexxR?
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What is meaning of class RexxDictionary in NetRexxR?
 
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Unfortunately, neither I nor Wikipedia know what a "DMSRVA tree" is.
George /* IBM Materials Licensed under International Components for Unicode */ /* Licence version 1.8.1 (ICU Licence) - Property of IBM */ /* IBM NetRexx */ /* Copyright (c) 1995-2009 IBM Corp. */ /* Copyright (c) 2011- RexxLA */ /* ------------------------------------------------------------------ */ /* netrexx.lang.RexxDictionary */ /* ------------------------------------------------------------------ */ /* Copyright IBM Corporation, 1996, 1997. All Rights Reserved. */ /* Author Mike Cowlishaw */ /* */ /* A Dictionary indexed by (Rexx) strings rather than by object */ /* references. */ /* */ /* Later: extend to be a full subclass of Dictionary, perhaps using */ /* DMSRVA trees. */ /* */ /* ------------------------------------------------------------------ */ /* 96.06.23 Initial version in NetRexx */ /* ------------------------------------------------------------------ */ package netrexx.lang options binary strictargs nodecimal noformat nodiag /** This defines the primary dictionary class for NetRexx. */ class RexxDictionary /* implements Dictionary */ --- currently on hold; using Hashtable in Rexx.nrx --# _______________________________________________ Ibm-netrexx mailing list [hidden email] Online Archive : http://ibm-netrexx.215625.n3.nabble.com/ |
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Must be a mainframe (Classic) Rexx structure, there is a google hit for:
which states that dmsrva is a new module for VM SP release 3. Also, there is a message from a terminal interface block; IRX also hints at Rexx 4 DECIMAL 248 TIB2TV2F IRXTVARS
TERMINATED
DUE TO A
FAILURE
IN DMSRVA best regards, René. On 10 okt. 2011, at 16:53, George Hovey wrote: Unfortunately, neither I nor Wikipedia know what a "DMSRVA tree" is. _______________________________________________ Ibm-netrexx mailing list [hidden email] Online Archive : http://ibm-netrexx.215625.n3.nabble.com/ |
RE: What is meaning of class RexxDictionary in NetRexxR?
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In reply to this post by George Hovey-2
Using Hashtable is probably sufficient for this.
The "DMSRVA tree" is a novel data structure developed/invented
by the late Laurie Griffiths and me around 1980. It was optimized for Rexx
variables lookup, with the cost of an addition/change to a variable and the
cost of a lookup balanced to match the expected/measured frequency of those
operations in typical Rex[x] programs.
'DMS' was the three-letter prefix for all Rexx modules at the
time; 'RVA' was short for "Rexx VAriables" .
Below is the overview of the DMSRVA tree, from the DMSRVA
assembler source. Nowadays I'd probably first consider a treap for this
rather than a special form of tree.
Mike
* Variables Data structure
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01940000
* 01950000 * The names of variables are held in a balanced binary tree. 01960000 * The tree is balanced in the sense that when any new node is 01970000 * added, the depth of left and right subtrees are 'balanced'. 01980000 * Depth means the longest path down through the subtree from 01990000 * the subtree root to a leaf. Adjustment will take place if 02000000 * the left and right depths differ by more than 1. Currently 02010000 * no node is deleted unless the whole subtree is deleted. 02020000 * Balancing is applied to each node in turn from where a new 02030000 * leaf is added to the root of the tree. The adjustment of 02040000 * a single node is not guaranteed to improve things (but will 02050000 * make them no worse). The balancing act applied to the 02060000 * whole path will ensure that the degree of imbalance is 02070000 * limited, and in particular trees with long paths containing 02080000 * only one branch (i.e. either right or left subtree empty) 02090000 * are impossible. Such paths would give performance no 02100000 * better than a simple linear search. 02110000 * 02120000 * Each node of the tree is a VARBLOK. The tree is sorted in 02130000 * that all variables within a left subtree will have names no 02140000 * longer than that of its root node. Those with names the 02150000 * same length will be alphabetically earlier (as defined by 02160000 * CLC and BL). For simple variables (no dots in name) that 02170000 * is the whole story. For complex variables (e.g. 'AB.I.J.') 02180000 * only the stem of their name ('AB.') will be in the primary 02190000 * tree. The rest of the name ('I.J.') after any substitution 02200000 * will lie in another tree whose anchor is pointed to by 02210000 * VBPTR. Note that the rest of the name can be null if the 02220000 * substituted value is null, and in this case the "name" in 02230000 * the subtree will be the null string. 02240000 * 02250000 * For EXPOSEd variables of procedures, the VBPTR high order 02260000 * bit means that this pointer leads to an earlier generation, 02270000 * (which in turn may, via the next VBPTR, lead to earlier 02280000 * generations). For EXPOSE of a stem, the VBPTR will point 02290000 * directly to the real anchor block, without intermediate 02300000 * chaining. (Since an anchor cannot be extended, there is 02310000 * no danger in having multiple pointers to it.) 02320000 * 02330000 * A block which is a dummy block, merely acting as a "place- 02340000 * holder" for an EXPOSE is marked by both VBPTR and VBLEN 02350000 * being 0. A variable which has been dropped is marked by 02360000 * VBPTR=0 and VBLEN=-1. 02370000 EJECT 02380000 * Picture of tree with the following variables:- 02390000 * A = 'abc' 02400000 * B = '15' 02410000 * C used to have the value 92 but has been dropped 02420000 * D = '3' 02430000 * AA = '2' 02440000 * A. = '21' 02450000 * A.1 = '12' 02460000 * A.2 = '31' 02470000 SPACE 02480000 * Nodes are shown as (left:right:vbptr:name:data) 02490000 * A null pointer is shown as 0 02500000 * Near to each node is shown the full name of the variable it 02510000 * represents. The node shown for A.? is the node for all 02520000 * variables beginning 'A.' which holds the anchor block for 02530000 * the secondary tree. 02540000 SPACE 2 02550000 * ROOTADDR-------------->(|) anchor block 02560000 * | +---+ 02570000 * | | | 02580000 * v | v 02590000 * (|:|:|:D:3) D 02600000 * | | 02610000 * | +--------------+ 02620000 * +---------------------+ | 02630000 * | +---+ | +------+ 02640000 * | | | | | | 02650000 * v | v v | v 02660000 * (|:|:|:B:15) B A.? (|:0:|:A.: (|)) 02670000 * +---+ | | | 02680000 * | +-------+ +------------+ | 02690000 * | +---+ | | +----+ | 02700000 * | | | | | | | | 02710000 * v | v v v | v | 02720000 * (0:0:|:A:abc) (0:0:0:C:92) (0:0:|:AA:2) | 02730000 * | 02740000 * A C (dropped) AA | 02750000 * | 02760000 * +-------------------------------+ 02770000 * | +---+ 02780000 * | | | 02790000 * v | v 02800000 * (|:|:|:1:12) A.1 02810000 * +-----------+ | 02820000 * | +------------------+ 02830000 * | +--+ | +---+ 02840000 * | | | | | | 02850000 * v | v v | v 02860000 * (0:0:|::21) A. A.2 (0:0:|:2:31) 02870000
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Re: What is meaning of class RexxDictionary in NetRexxR?
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In reply to this post by rvjansen
D'oh, I should have picked up on that reference. That is definitely
old, since at the time Netrexx was being written, DMSRVA had been renamed to IXXRVA. A dmsrva tree is a balanced binary tree that was used for the Rexx variable tree in Mike's original classic Rexx interpreter. There's a C++ version of that code in ooRexx. Not sure you'd want to port that version to complete this implementation since it did not handle deletions. There is a fully ooRexx implementation in one of the examples I used in a past symposium talk. Rick On Mon, Oct 10, 2011 at 11:32 AM, René Jansen <[hidden email]> wrote: > Must be a mainframe (Classic) Rexx structure, there is a google hit for: > http://bitsavers.org/pdf/ibm/370/VM_SP/SC24-5240-0_VM_SP_Release_3_Guide_Jul83.pdf > which states that dmsrva is a new module for VM SP release 3. > Also, there is a message from a terminal interface block; IRX also hints at > Rexx > 4 DECIMAL 248 TIB2TV2F IRXTVARS TERMINATED DUE TO A FAILURE IN DMSRVA > best regards, > René. > > > > On 10 okt. 2011, at 16:53, George Hovey wrote: > > Unfortunately, neither I nor Wikipedia know what a "DMSRVA tree" is. > George > > > /* IBM Materials Licensed under International Components for Unicode */ > /* Licence version 1.8.1 (ICU Licence) - Property of IBM */ > /* IBM NetRexx */ > /* Copyright (c) 1995-2009 IBM Corp. */ > /* Copyright (c) 2011- RexxLA */ > /* ------------------------------------------------------------------ */ > /* netrexx.lang.RexxDictionary */ > /* ------------------------------------------------------------------ */ > /* Copyright IBM Corporation, 1996, 1997. All Rights Reserved. */ > /* Author Mike Cowlishaw */ > /* */ > /* A Dictionary indexed by (Rexx) strings rather than by object */ > /* references. */ > /* */ > /* Later: extend to be a full subclass of Dictionary, perhaps using */ > /* DMSRVA trees. */ > /* */ > /* ------------------------------------------------------------------ */ > /* 96.06.23 Initial version in NetRexx */ > /* ------------------------------------------------------------------ */ > package netrexx.lang > options binary strictargs nodecimal noformat nodiag > > /** > This defines the primary dictionary class for NetRexx. > */ > > class RexxDictionary /* implements Dictionary */ > > --- currently on hold; using Hashtable in > Rexx.nrx --# > > _______________________________________________ > Ibm-netrexx mailing list > [hidden email] > Online Archive : http://ibm-netrexx.215625.n3.nabble.com/ > > > > _______________________________________________ > Ibm-netrexx mailing list > [hidden email] > Online Archive : http://ibm-netrexx.215625.n3.nabble.com/ > > > _______________________________________________ Ibm-netrexx mailing list [hidden email] Online Archive : http://ibm-netrexx.215625.n3.nabble.com/ |
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On 10/10/11 16:01 Rick McGuire said:
> A dmsrva tree is a balanced binary tree that was used for > the Rexx variable tree in Mike's original classic Rexx > interpreter. ... There is a fully ooRexx implementation > in one of the examples I used in a past symposium talk. And, if I'm not mistaken, the only native ooRexx contribution to the Wiki Sample Code section. There are some OpenOffice.org code snippets that require BSF4Rexx, and a dead-end link for some Lotus Notes code. -Chip- _______________________________________________ Ibm-netrexx mailing list [hidden email] Online Archive : http://ibm-netrexx.215625.n3.nabble.com/ |
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In reply to this post by rickmcguire
I personally, at this time now (2011) would like to advise to use so called
RED-BLACK trees..... They are auto-balancing, as far as I do understand this approach. :-) Thomas Schneider. =================================================== Am 10.10.2011 18:01, schrieb Rick McGuire: > D'oh, I should have picked up on that reference. That is definitely > old, since at the time Netrexx was being written, DMSRVA had been > renamed to IXXRVA. A dmsrva tree is a balanced binary tree that was > used for the Rexx variable tree in Mike's original classic Rexx > interpreter. There's a C++ version of that code in ooRexx. Not sure > you'd want to port that version to complete this implementation since > it did not handle deletions. There is a fully ooRexx implementation > in one of the examples I used in a past symposium talk. > > Rick > > On Mon, Oct 10, 2011 at 11:32 AM, René Jansen<[hidden email]> wrote: >> Must be a mainframe (Classic) Rexx structure, there is a google hit for: >> http://bitsavers.org/pdf/ibm/370/VM_SP/SC24-5240-0_VM_SP_Release_3_Guide_Jul83.pdf >> which states that dmsrva is a new module for VM SP release 3. >> Also, there is a message from a terminal interface block; IRX also hints at >> Rexx >> 4 DECIMAL 248 TIB2TV2F IRXTVARS TERMINATED DUE TO A FAILURE IN DMSRVA >> best regards, >> René. >> >> >> >> On 10 okt. 2011, at 16:53, George Hovey wrote: >> >> Unfortunately, neither I nor Wikipedia know what a "DMSRVA tree" is. >> George >> >> >> /* IBM Materials Licensed under International Components for Unicode */ >> /* Licence version 1.8.1 (ICU Licence) - Property of IBM */ >> /* IBM NetRexx */ >> /* Copyright (c) 1995-2009 IBM Corp. */ >> /* Copyright (c) 2011- RexxLA */ >> /* ------------------------------------------------------------------ */ >> /* netrexx.lang.RexxDictionary */ >> /* ------------------------------------------------------------------ */ >> /* Copyright IBM Corporation, 1996, 1997. All Rights Reserved. */ >> /* Author Mike Cowlishaw */ >> /* */ >> /* A Dictionary indexed by (Rexx) strings rather than by object */ >> /* references. */ >> /* */ >> /* Later: extend to be a full subclass of Dictionary, perhaps using */ >> /* DMSRVA trees. */ >> /* */ >> /* ------------------------------------------------------------------ */ >> /* 96.06.23 Initial version in NetRexx */ >> /* ------------------------------------------------------------------ */ >> package netrexx.lang >> options binary strictargs nodecimal noformat nodiag >> >> /** >> This defines the primary dictionary class for NetRexx. >> */ >> >> class RexxDictionary /* implements Dictionary */ >> >> --- currently on hold; using Hashtable in >> Rexx.nrx --# >> >> _______________________________________________ >> Ibm-netrexx mailing list >> [hidden email] >> Online Archive : http://ibm-netrexx.215625.n3.nabble.com/ >> >> >> >> _______________________________________________ >> Ibm-netrexx mailing list >> [hidden email] >> Online Archive : http://ibm-netrexx.215625.n3.nabble.com/ >> >> >> > _______________________________________________ > Ibm-netrexx mailing list > [hidden email] > Online Archive : http://ibm-netrexx.215625.n3.nabble.com/ > > -- Thomas Schneider (Founder of www.thsitc.com) Member of the Rexx Languge Asscociation (www.rexxla.org) Member of the NetRexx Developer's Team (www.netrexx.org) _______________________________________________ Ibm-netrexx mailing list [hidden email] Online Archive : http://ibm-netrexx.215625.n3.nabble.com/
Thomas Schneider, Vienna, Austria (Europe) :-)
www.thsitc.com www.db-123.com |
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Wooo... does that make me feel old.
I took "Data Structures Design" before B-trees were invented. Knuth was still working on _Sorting_and_Searching_. I had to learn all that stuff on the job which, parenthetically, was probably where I first encountered the 'theoretical vs. practical' disdain from my boss (an accountant who was made Director of Data Processing because he knew how to use a non-programmable mechanical accounting machine). I think I need a nap... -Chip- On 10/11/11 16:34 Thomas Schneider said: > I personally, at this time now (2011) would like to advise to use so called > RED-BLACK trees..... > > They are auto-balancing, as far as I do understand this approach. :-) > > =================================================== > Am 10.10.2011 18:01, schrieb Rick McGuire: >> D'oh, I should have picked up on that reference. That is definitely >> old, since at the time Netrexx was being written, DMSRVA had been >> renamed to IXXRVA. A dmsrva tree is a balanced binary tree that was >> used for the Rexx variable tree in Mike's original classic Rexx >> interpreter. _______________________________________________ Ibm-netrexx mailing list [hidden email] Online Archive : http://ibm-netrexx.215625.n3.nabble.com/ |
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Hello Chip,
I'm already feeeling *old* (with my left heart, 65) as well. As I do have also a right heart (13), I'm still in the process to: - survive - learn - etc etc RED-BLACK Trees (simply Google, as you do like so much) are the current state of the art for self-balancing trees. There is a lot of (scientific) doc about this. Enjoy the reading... Thomas. PS: I do have Knuth's books on my desk, but as you see, time is progressing, as well as knowledge how to solve common problems. =================================================== Am 11.10.2011 19:56, schrieb Chip Davis: > Wooo... does that make me feel old. > > I took "Data Structures Design" before B-trees were invented. Knuth > was still working on _Sorting_and_Searching_. I had to learn all that > stuff on the job which, parenthetically, was probably where I first > encountered the 'theoretical vs. practical' disdain from my boss (an > accountant who was made Director of Data Processing because he knew > how to use a non-programmable mechanical accounting machine). > > I think I need a nap... > > -Chip- > > On 10/11/11 16:34 Thomas Schneider said: >> I personally, at this time now (2011) would like to advise to use so >> called >> RED-BLACK trees..... >> >> They are auto-balancing, as far as I do understand this approach. :-) >> >> =================================================== >> Am 10.10.2011 18:01, schrieb Rick McGuire: >>> D'oh, I should have picked up on that reference. That is definitely >>> old, since at the time Netrexx was being written, DMSRVA had been >>> renamed to IXXRVA. A dmsrva tree is a balanced binary tree that was >>> used for the Rexx variable tree in Mike's original classic Rexx >>> interpreter. > > _______________________________________________ > Ibm-netrexx mailing list > [hidden email] > Online Archive : http://ibm-netrexx.215625.n3.nabble.com/ > > -- Thomas Schneider (Founder of www.thsitc.com) Member of the Rexx Languge Asscociation (www.rexxla.org) Member of the NetRexx Developer's Team (www.netrexx.org) _______________________________________________ Ibm-netrexx mailing list [hidden email] Online Archive : http://ibm-netrexx.215625.n3.nabble.com/
Thomas Schneider, Vienna, Austria (Europe) :-)
www.thsitc.com www.db-123.com |
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