No subject

of chars that can be accessed from one to another.
For example, given the sequence:
"abcde"
In table below chars in a left column can access a list of chars in the
right column:
a | b c d
e

b | c d
e

c | d
e

d |
e


Then chains for this example will be:
abcde, acde, ade, ae,
bcde, bde, be,
cde, cd, ce,
de

*** My incomplete result,
which I get running my program (see at the end of this message):
('a','b'),('b','c'),('c','d'),('d','e'), -- abcde,
('c','e'), -- ce,
('b','d'),('d','e'), -- bde,
('b','e') -- be,
('a','c'),('c','d'),('d','e'), -- acde
('c','e'),
('a','d'),('d','e'), -- ade,
('a','e') -- ae

Sequence 'abcde'  contains 'bcde', 'cde', 'cd', 'de'. How to add all these
sub-sequences as a separate sequences in my output?
And I have 'ce' sequence duplicated, which I don't need.
Also, how to output chains as a list of lists? Such as:
[[abcde, acde, ade, ae,]
[bcde, bde, be,]
[cde, cd, ce,]
de]]

*** my code

test = chains testPairs 'a' []
testPairs = pairs testSeq
testSeq = "abcde"

-- From a list of '((from,to),1)' pairs build char
chains

-- Char chain is a list of chars: [from1, to1 = from2, to2 = from3, to3 =
from4, ...]
-- 'pairList' - a list of
pairs


chains pairList from chainList  = chainWrk (nextTo pairList from) from
chainList
  where
    chainWrk [] from  chainList  = chainList
    chainWrk (to:tos) from chainList  =
      chainWrk tos from (chains pairList to (chainList ++ [(from,to)]))

-- Find direct neighbors for
'from'

nextTo pairList from =
  toList (findPairs pairList from) []

-- From a list of '((from,to),1)' pairs build a list of
'to'-s
toList [] tos = tos
toList (((from,to),len):ps) tos  = toList ps (tos ++ [to])

-- From 'pairList' find elements with 'from' equal to
'start'
-- 'pairList' is a list of '((from,to),1)'
pairs

findPairs pairList search  = filter (flt search) pairList
                          where
                            flt search ((from, to), len) = search == from

-- From a sequence of chars buid a list of '((from,to),1)'
pairs
pairs []  = []
pairs (x:xs) = pairWrk x xs [] ++ pairs xs

pairWrk hd [] pairLst = pairLst
pairWrk hd (x:xs) pairLst = pairWrk hd xs (pairLst ++ [((hd,x),1)])

--90e6ba6e83661ea9d304a454b901
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: base64
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--90e6ba6e83661ea9d304a454b901--