aboutsummaryrefslogtreecommitdiff
path: root/src/HaddockLex.hs
blob: 000d62f0563d760a941084c426f7f91c73595927 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
--
-- Haddock - A Haskell Documentation Tool
--
-- (c) Simon Marlow 2002
--

module HaddockLex ( 
	Token(..), 
	tokenise 
 ) where

import Char
import HsSyn
import HsLexer hiding (Token)
import HsParseMonad

data Token
  = TokPara
  | TokNumber
  | TokBullet
  | TokSpecial Char
  | TokIdent [HsQName]
  | TokString String
  | TokURL String
  | TokBirdTrack
  deriving Show

isSpecial c     = c `elem` ['\"', '@', '/']
isSingleQuote c = c `elem` ['\'', '`']
isIdent c       = isAlphaNum c || c == '_'

-- simple finite-state machine for tokenising the doc string

-- ----------------------------------------------------------------------------
-- At the beginning of a paragraph, we throw away initial whitespace

tokenise :: String -> [Token]
tokenise "" = []
tokenise str = case str of
  '<':cs  -> tokenise_url cs
  '\n':cs -> tokenise_newline cs
  c:cs 	| isSingleQuote c -> tokenise_identifier c cs
	| isSpecial c     -> TokSpecial c : tokenise1 cs
  _other  -> tokenise_string "" str

tokenise_newline cs =
 case dropWhile nonNewlineSpace cs of
   '\n':cs -> TokPara : tokenise_para cs -- paragraph break
   '>':cs  -> TokBirdTrack : tokenise_birdtrack cs -- bird track
   _other  -> tokenise_string "" cs

tokenise_para cs =
  case dropWhile nonNewlineSpace cs of   
	-- bullet:  '*'
   '*':cs  -> TokBullet  : tokenise cs
	-- bullet: '-'
   '-':cs  -> TokBullet  : tokenise cs
	-- enumerated item: '1.'
   '>':cs  -> TokBirdTrack : tokenise_birdtrack cs
	-- bird track
   str | (ds,'.':cs) <- span isDigit str, not (null ds)
		-> TokNumber : tokenise cs
	-- enumerated item: '(1)'
   '(':cs | (ds,')':cs') <- span isDigit cs, not (null ds)
		-> TokNumber : tokenise cs'
   other -> tokenise cs

nonNewlineSpace c = isSpace c && c /= '\n'

-- ----------------------------------------------------------------------------
-- Within a paragraph, we don't throw away any whitespace (except before a
-- birdtrack, and before a paragraph break).

tokenise1 :: String -> [Token]
tokenise1 str = tokenise_string "" str

-- found a single quote, check whether we have an identifier...
tokenise_identifier q cs =
  let (ident,rest) = break (not.isIdent) cs in
  case (rest, strToHsQNames ident) of
    (c:cs, Just names) | isSingleQuote c -> TokIdent names : tokenise1 cs
    _other -> tokenise_string [q] cs

tokenise_url cs =
  let (url,rest) = break (=='>') cs in
  TokURL url : case rest of
		 '>':rest -> tokenise1 rest
		 _ -> tokenise1 rest

tokenise_string str cs = 
  case cs of
    []        -> tokString str []
    '\\':c:cs -> tokenise_string (c:str) cs
    '\n':cs   -> tokenise_string_newline str cs
    '<':cs    -> tokString str (tokenise_url cs)
    c:cs | isSpecial c     -> tokString str (TokSpecial c : tokenise1 cs)
	 | isSingleQuote c -> tokString str (tokenise_identifier c cs)
         | otherwise 	   -> tokenise_string (c:str) cs

tokenise_string_newline str cs =
  case dropWhile nonNewlineSpace cs  of
   '\n':cs -> tokString str (TokPara : tokenise_para cs)
		-- paragraph break: throw away all whitespace
   '>':cs  -> tokString ('\n':str) (TokBirdTrack : tokenise_birdtrack cs)
		-- keep the \n, but throw away any space before the '>'
   _other  -> tokenise_string ('\n':str) cs
		-- don't throw away whitespace at all

tokString [] rest = rest
tokString cs rest = TokString (reverse cs) : rest

-- A bird-tracked line is verbatim, no markup characters are interpreted
tokenise_birdtrack cs = 
  let (line, rest) = break (=='\n') cs in
  TokString line : tokenise1 rest

-- -----------------------------------------------------------------------------
-- Lex a string as a Haskell identifier

strToHsQNames :: String -> Maybe [HsQName]
strToHsQNames str
 = case lexer (\t -> returnP t) str (SrcLoc 1 1) 1 1 [] of
	Ok _ (VarId str)
	   -> Just [ UnQual (HsVarName (HsIdent str)) ]
        Ok _ (QVarId (mod,str))
 	   -> Just [ Qual (Module mod) (HsVarName (HsIdent str)) ]
	Ok _ (ConId str)
	   -> Just [ UnQual (HsTyClsName (HsIdent str)),
		     UnQual (HsVarName (HsIdent str)) ]
        Ok _ (QConId (mod,str))
	   -> Just [ Qual (Module mod) (HsTyClsName (HsIdent str)),
		     Qual (Module mod) (HsVarName (HsIdent str)) ]
        Ok _ (VarSym str)
	   -> Just [ UnQual (HsVarName (HsSymbol str)) ]
        Ok _ (ConSym str)
	   -> Just [ UnQual (HsTyClsName (HsSymbol str)),
		     UnQual (HsVarName (HsSymbol str)) ]
        Ok _ (QVarSym (mod,str))
	   -> Just [ Qual (Module mod) (HsVarName (HsSymbol str)) ]
        Ok _ (QConSym (mod,str))
	   -> Just [ Qual (Module mod) (HsTyClsName (HsSymbol str)),
		     Qual (Module mod) (HsVarName (HsSymbol str)) ]
	other
	   -> Nothing