Annotation of /sml/trunk/src/cm/parse/parse.sml

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1 :	blume	270	(*
2 :			* Parser for CM description files.
3 :			*
4 :			* (C) 1999 Lucent Technologies, Bell Laboratories
5 :			*
6 :			* Author: Matthias Blume (blume@kurims.kyoto-u.ac.jp)
7 :			*)
8 :	blume	268	signature CMPARSE = sig
9 :	blume	286	val parse : Primitive.configuration -> AbsPath.t -> CMSemant.group option
10 :	blume	268	end
11 :
12 :			structure CMParse :> CMPARSE = struct
13 :
14 :			val lookAhead = 30
15 :
16 :			structure S = GenericVC.Source
17 :			structure EM = GenericVC.ErrorMsg
18 :			structure SM = GenericVC.SourceMap
19 :			structure P = GenericVC.Control.Print
20 :
21 :			structure CMLrVals = CMLrValsFun (structure Token = LrParser.Token)
22 :			structure CMLex = CMLexFun (structure Tokens = CMLrVals.Tokens)
23 :			structure CMParse =
24 :			JoinWithArg (structure ParserData = CMLrVals.ParserData
25 :			structure Lex = CMLex
26 :			structure LrParser = LrParser)
27 :
28 :	blume	286	fun parse primconf group = let
29 :	blume	270
30 :	blume	286	val groupreg = GroupReg.new ()
31 :			val fnpolicy = FilenamePolicy.default
32 :			val params = { groupreg = groupreg,
33 :			fnpolicy = fnpolicy,
34 :	blume	295	primconf = primconf,
35 :			keep_going = false }
36 :	blume	268
37 :	blume	294	val gc = ref AbsPathMap.empty (* the "group cache" *)
38 :	blume	273
39 :	blume	294	fun mparse (group, groupstack) =
40 :			case AbsPathMap.find (!gc, group) of
41 :			SOME g => g
42 :			| NONE => let
43 :			val g = parse' (group, groupstack)
44 :			in
45 :			gc := AbsPathMap.insert (!gc, group, g);
46 :			g
47 :			end
48 :	blume	273
49 :	blume	294	and parse' (group, groupstack) = let
50 :	blume	286	(* checking for cycles among groups and printing them nicely *)
51 :	blume	294	fun findCycle ([], _) = []
52 :			| findCycle ((h as (g, (s, p1, p2))) :: t, cyc) =
53 :			if AbsPath.compare (g, group) = EQUAL then rev (h :: cyc)
54 :			else findCycle (t, h :: cyc)
55 :			fun report ((g, (s, p1, p2)), hist) = let
56 :			fun pphist pps = let
57 :			fun loop (_, []) = ()
58 :			| loop (g0, (g, (s, p1, p2)) :: t) = let
59 :			val s = EM.matchErrorString s (p1, p2)
60 :			in
61 :			PrettyPrint.add_string pps s;
62 :			PrettyPrint.add_string pps ": importing ";
63 :			PrettyPrint.add_string pps (AbsPath.spec g0);
64 :			PrettyPrint.add_newline pps;
65 :			loop (g, t)
66 :			end
67 :	blume	273	in
68 :	blume	294	PrettyPrint.add_newline pps;
69 :			loop (g, hist)
70 :	blume	273	end
71 :			in
72 :	blume	294	EM.error s (p1, p2) EM.COMPLAIN
73 :			("group hierarchy forms a cycle with " ^
74 :			AbsPath.spec group)
75 :			pphist
76 :	blume	273	end
77 :
78 :	blume	294	(* normal processing -- used when there is no cycle to report *)
79 :			fun normal_processing () = let
80 :			val currentDir = AbsPath.dir group
81 :			val context = AbsPath.relativeContext (AbsPath.dir group)
82 :			val filename = AbsPath.name group
83 :			val _ = Say.vsay (concat ["[scanning ", filename, "]\n"])
84 :			val stream = TextIO.openIn filename
85 :			val errcons = { linewidth = !P.linewidth,
86 :			flush = P.flush,
87 :			consumer = P.say }
88 :			val source = S.newSource (filename, 1, stream, false, errcons)
89 :			val sourceMap = #sourceMap source
90 :			val _ = GroupReg.register groupreg (group, source)
91 :
92 :	blume	297	(* We can hard-wire the source into this
93 :			* error function because the function is only for
94 :			* immediate use and doesn't get stored into persistent
95 :			* data structures. *)
96 :			fun error r m =
97 :			EM.error source r EM.COMPLAIN m EM.nullErrorBody
98 :
99 :	blume	294	(* recParse returns a group (not an option).
100 :			* This function is used to parse aliases and sub-groups.
101 :			* Errors are propagated by explicitly setting the
102 :			* "anyErrors" flag of the parent group. *)
103 :			fun recParse (p1, p2) p = let
104 :			val groupstack' = (group, (source, p1, p2)) :: groupstack
105 :	blume	286	in
106 :	blume	294	case mparse (p, groupstack') of
107 :			NONE => (#anyErrors source := true;
108 :			CMSemant.emptyGroup group)
109 :			| SOME res => res
110 :	blume	286	end
111 :	blume	294	handle exn as IO.Io _ =>
112 :			(error (p1, p2) (General.exnMessage exn);
113 :			CMSemant.emptyGroup group)
114 :
115 :	blume	297	fun doMember (p, p1, p2, c) =
116 :	blume	294	CMSemant.member (params, recParse (p1, p2))
117 :	blume	297	{ sourcepath = p, class = c,
118 :			group = (group, (p1, p2)) }
119 :	blume	294
120 :			val lexarg = let
121 :			(* local state *)
122 :			val depth = ref 0
123 :			val curstring = ref []
124 :			val startpos = ref 0
125 :			val instring = ref false
126 :			(* handling comments *)
127 :			fun enterC () = depth := !depth + 1
128 :			fun leaveC () = let
129 :			val d = !depth - 1
130 :			in
131 :			depth := d;
132 :			d = 0
133 :			end
134 :			(* handling strings *)
135 :			fun newS pos =
136 :			(instring := true; curstring := []; startpos := pos)
137 :			fun addS c = curstring := c :: !curstring
138 :			fun addSC (s, offs) =
139 :			addS (chr (ord (String.sub (s, 2)) - offs))
140 :			fun addSN (s, pos) = let
141 :			val ns = substring (s, 1, 3)
142 :			val n = Int.fromString ns
143 :			in
144 :			addS (chr (valOf n))
145 :			handle _ =>
146 :			error (pos, pos + size s)
147 :			("illegal decimal char spec: " ^ ns)
148 :			end
149 :			fun getS (pos, tok) =
150 :			(instring := false;
151 :			tok (implode (rev (!curstring)), !startpos, pos))
152 :			(* handling EOF *)
153 :			fun handleEof () = let
154 :			val pos = SM.lastChange sourceMap
155 :			in
156 :			if !depth > 0 then
157 :			error (pos, pos)
158 :			"unexpected end of input in comment"
159 :			else if !instring then
160 :			error (pos, pos)
161 :			"unexpected end of input in string"
162 :			else ();
163 :			pos
164 :			end
165 :			(* handling line breaks *)
166 :			fun newline pos = SM.newline sourceMap pos
167 :			in
168 :			{ enterC = enterC,
169 :			leaveC = leaveC,
170 :			newS = newS,
171 :			addS = addS,
172 :			addSC = addSC,
173 :			addSN = addSN,
174 :			getS = getS,
175 :			handleEof = handleEof,
176 :			newline = newline,
177 :			error = error }
178 :			end
179 :
180 :			fun inputc k = TextIO.input stream
181 :
182 :			val lexer = CMLex.makeLexer inputc lexarg
183 :			val tokenStream = LrParser.Stream.streamify lexer
184 :			val (parseResult, _) =
185 :			CMParse.parse (lookAhead, tokenStream,
186 :			fn (s,p1,p2) => error (p1, p2) s,
187 :	blume	297	(group, context, error, recParse,
188 :			doMember, params))
189 :	blume	268	in
190 :	blume	294	TextIO.closeIn stream;
191 :			if !(#anyErrors source) then NONE
192 :			else SOME parseResult
193 :	blume	268	end
194 :	blume	294	handle LrParser.ParseError => NONE
195 :	blume	268	in
196 :	blume	294	case findCycle (groupstack, []) of
197 :			h :: t => (report (h, t); NONE)
198 :			| [] => normal_processing ()
199 :	blume	268	end
200 :	blume	294
201 :	blume	268	in
202 :	blume	294	mparse (group, [])
203 :	blume	274	end
204 :	blume	268	end

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