J implementation places an artificial limit on the lengths of
names. try
(255$'a')=.0
(256$'a')=.0
|limit error
| (256$'a') =.0
Ср, 03 сен 2014, jprogramming написал(а):
> strbracket =: {.@:[ , ] , {:@[
> joinB =: (1 : ' ((- # m)&}.@;@(,&m&.>"1))')(@: (] : ;))
> nums2name =: 'NUM' joinB@:cut@:(('.';'F') rplc~ ('_';'n') rplc~ ":)^:(1 4 8
> 16 64 128 e.~ 3!:0)
> boxsandnums2name =: [: (('B0X_',:'B0oX') strbracket '_' joinB )^:(32 = 3!:0
> ) L:1 ^:_ ^:(1 <L.) nums2name L:0
> text2name =: ('_' joinB)@:,&boxopen&([: cut (AlphaNum_j_, ' ')&(-.~ -.~
> ]))^:(2 = 3!:0)
> buildvar =: ([: ('_'joinB)@:('_'&cut)@:('_'joinB) [: ('_'
> joinB)@:,&boxopen&boxsandnums2name&.> text2name L:0 )@:boxopen@:(] :;)
>
> joinB is an adverb similar to ;: inv. ' ' JoinB is identical to ;: inv.
> Except rather than space, any string can be used to join together boxes, and
> it can be used dyadically implicitly boxing the arguments.
>
> 'fd' '_'joinB 'hh'
> fd_hh
>
> '_'joinB <'hh'
> hh
>
> '_|_'joinB ;: 'fb hh try'
> fb_|_hh_|_try
>
>
> nums2name will take a numeric list (or scalar) and strip out _ and . It will
> also insert 'NUM' between numeric list items.
>
> nums2name each _4.32;i.2 3
> ┌─────┬──────────────────┐
> │n4F32│0NUM1NUM23NUM4NUM5│
> └─────┴──────────────────┘
> the above may seem buggy (23) but cleaner separation for higher dimensional
> lists can be obtained by boxing them.
>
> nums2name each _4.32;<"1 i.2 3
> ┌─────┬─────────┬─────────┐
> │n4F32│0NUM1NUM2│3NUM4NUM5│
> └─────┴─────────┴─────────┘
>
> nums2name each 'asdf';_4.32; i.2 3
NB. leaves non numeric data unchanged
> ┌────┬─────┬──────────────────┐
> │asdf│n4F32│0NUM1NUM23NUM4NUM5│
> └────┴─────┴──────────────────┘
>
>
> boxsandnums2name calls nums2names first such that all data processed is
> strings and boxes of strings. There is a neat recursive process I discovered
> for flattening trees. It tunnels down to L:1 level, and flattens that level
> converting the L:1 cell to a string, then recurses "upwards" until there are
> no more L:2+ cells.
>
> boxsandnums2name (5!:2 <'nums2name')
> B0X_B0X_B0X_B0X_B0X_B0X_n3_&_}.B0oX_@_;B0oX_@_B0X_B0X_B0X_,_&_NUMB0oX_&._>B0oX_"_1B0oXB0oX_@:_cutB0oX_@:_B0X_B0X_._FB0oX_B0X_rplc_~B0oX_B0X_B0X___nB0oX_B0X_rplc_~B0oX_":B0oXB0oXB0oX_^:_B0X_1NUM4NUM8NUM16NUM64NUM128_B0X_e._~B0oX_B0X_3_!:_0B0oXB0oXB0oX
>
> text2name strips all punctuation from a string then replaces (possible
> multiple) spaces with '_'
>
> buildvar makes the hash. Using all of the previous functions.
>
> for strings, words in a string will hash to same value as a list of boxed
> words.
> buildvar 'asd fsdf sdf sd fsd f'
> asd_fsdf_sdf_sd_fsd_f
> buildvar ;:'asd fsdf sdf sd fsd f'
> asd_fsdf_sdf_sd_fsd_f
>
> same as this dyadic call:
> 'asd' buildvar ' fsdf sdf sd fsd f'
> asd_fsdf_sdf_sd_fsd_f
>
> 'asd' buildvar ' fsdf sdf sd fsd f'; 123 _33.3
> asd_fsdf_sdf_sd_fsd_f_123NUMn33F3
>
> for numbers though, boxed nums hash differently than a list of numbers
>
> buildvar 1 2.4 _33
> 1NUM2F4NUMn33
> buildvar ;/ 1 2.4 _33
> 1_2F4_n33
> buildvar << ;/ 1 2.4 _33
> B0X_B0X_1_2F4_n33B0oXB0oX
>
> You may note that numbers do not produce a legal variable name if the leading
> character is a number. The presented routine creates the core hash. Its
> expected that a classifying prefix would be appended, and a locale would be
> attached.
>
> boxed positive integers and their text version hash identically. As strings
> though, negatives and decimal points are stripped off.
>
> buildvar ;: 'sdf sdf dsdff 1 2.4 _33'
> sdf_sdf_dsdff_1_24_33
> buildvar ".^:(0 -.@-: 0&".) each ;: 'sdf sdf dsdff 1 2.4 _33'
> sdf_sdf_dsdff_1NUM2F4NUMn33
>
>
>
> doesn't work great (too many symbols stripped out) for J code, but it still
> works:
> buildvar quote 5!:5 <'nums2name'
> 3NUM1cutF_rplc_n_rplc_1_4_8_16_64_128_e_30
>
> buildvar (5!:2 <'nums2name')
> B0X_B0X_B0X_B0X_B0X_n3_B0oX_B0oX_B0X_B0X_B0X_NUMB0oX_B0oX_1B0oXB0oX_cutB0oX_B0X_B0X_FB0oX_B0X_rplc_B0oX_B0X_B0X_nB0oX_B0X_rplc_B0oX_B0oXB0oXB0oX_B0X_1NUM4NUM8NUM16NUM64NUM128_B0X_e_B0oX_B0X_3_0B0oXB0oX
>
> The hash is symetrical for Alpha Num and space. That is, if no symbol has
> been stripped off, then the original data structure can be recovered. It is
> somewhat human readable.
>
> As to why, it can hash anything, and since the hash value is the basis for a
> legal J name, anything can be associated with anything. A prefix can provide
> context for what you are associating and so what to do with the content, and
> allows classification such that multiple data (dictionaries) can be held
> within a single locale.
>
> Compared to a boxed dictionary structure, value retrieval is faster. By
> holding a tree structure within prefixes, tree traversal is also faster. A
> linked list where the hash of the data gives the location of the next node is
> an application. If the data is reversible (boxedalphanumspace) then you also
> get double linked list. Because of infinite boxing, all data can be
> transformed into alphanumspace.
>
> Compared to symbols, the hash is permanent, repeatable, serializable, and
> shareable among machines.
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm
--
regards,
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