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||names defined in this file are not in scope for users - they are part
||of the internal mechanisms of the Miranda system.
||the following three identifiers are "untypeable" and defined internally
||changetype::*->** ||primitive function, semantically equivalent to id
||first::*->** ||gets first element of a tuple
||rest::*->** ||gets rest of a tuple (i.e. without first component)
||offside::[char] ||defined internally and used by indent, see below
diagonalise :: [[*]]->[*] ||used by [//] comprehensions
diagonalise x = diag 1 x ||when nested does "cantorian" diagonalisation
diag n [] = []
diag n x = map hd px++diag (#px+1)rest, otherwise
where
px = filter (~=[]) (take n x)
rest = map tl px ++ drop n x
listdiff::[*]->[*]->[*] ||listdiff defines the action of "--"
listdiff x [] = x
listdiff x (b:y) = listdiff (remove b x) y
remove b [] = []
remove b (a:x) = x, if a=b
= a:remove b x, otherwise
showbool::bool->[char]
showbool True = "True"
showbool False = "False"
||shownum defined internally
base r x = "0", if x=0 ||base is used by charname
= f x, otherwise
where
f 0 = []
f n = f(n div r) ++ [mkdigit(n mod r)]
mkdigit n = decode(n + code '0'), if n<10
= decode(n - 10 + code 'a'), if 10<=n<36
showchar::char->[char]
showchar x = "'" ++ charname x ++ "'"
||note - charname has the right conventions for showchar
||i.e. ' is escaped and " is not escaped - showstring inverts this
charname '\\' = "\\\\"
charname '\'' = "\\\'"
charname x = [x], if 32 <= code x < 127 \/ 160 <= code x < 256
charname '\a' = "\\a"
charname '\b' = "\\b"
charname '\f' = "\\f"
charname '\n' = "\\n"
charname '\r' = "\\r"
charname '\t' = "\\t"
charname '\v' = "\\v"
charname x = "\\" ++ pad 3 (base 10 n), if n<1000 ||H=this case only & no pad
= "\\x" ++ pad 4 (base 16 n), if n<=0xffff
= "\\X" ++ pad 6 (base 16 n), otherwise
where
n = code x
pad w s = rep(w-#s)'0'++s
rep n x = [], if n<=0
= x:rep (n-1) x, otherwise
showlist::(*->[char])->[*]->[char]
showlist f x = '[':rest
where
rest = "]", if x=[]
= f(hd x)++foldr g "]" (tl x), otherwise
g a s = ',':f a++s
showstring::[char]->[char]
showstring x = '"' : showstr x
showstr [] = "\""
showstr ('"':x) = "\\\"" ++ showstr x
showstr (a:x) = s ++ showstr x ||for Haskell style padding use s1 here
where ||see also line marked H above
s = charname a
|| s1 = s ++ "\\&", if clash s x
|| = s, otherwise
|| clash ('\\':c:cs) (d:ds) = digit c & digit d
|| clash s x = False
digit c = '0' <= c <= '9'
shownum1::num->[char]
shownum1 n = "("++shownum n++")", if n<0
= shownum n, otherwise
showparen::(*->[char])->*->[char]
showparen f x = "("++f x++")"
showpair::(*->[char])->(**->[char])->***->[char]
showpair f1 f2 tup = f1(first tup)++","++f2(rest tup)
showvoid::()->[char]
showvoid () = "()"
showfunction::(*->**)->[char]
showfunction x = "<function>"
showabstract::*->[char]
showabstract x = "<abstract ob>"
showwhat::*->[char]
showwhat x = error "undeclared show-function", if x=x
||the following function is used to implement the offside rule (under %bnf)
indent :: *->**->** || * is type of `col' function, ** is parser
outdent :: *->* || * is a parser
indent = changetype indent1
outdent = changetype outdent1
indent1 col f ((a,s):x)
= f ((a,s):cutoff col (col s) x), if a~=offside
indent1 col f x = f x
cutoff col n = g
where
g ((a,s):x) = (a,s):g x, if col s>=n
= (offside,s):(a,s):x, otherwise
g [] = []
outdent1 f = reconstruct.f
reconstruct (m:x) = m:g x
where
g ((a,s):x) = x, if a=offside
g (t:x) = t:g x
g [] = []
reconstruct fail = fail ||internal repn of failure is a non-CONS object
||offside is defined internally and differs from every string
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