Annotation of /sml/trunk/src/ml-yacc/lib/lrtable.sml

Parent Directory | Revision Log

---

Revision 250 - (view) (download)

1 :	monnier	249	(* ML-Yacc Parser Generator (c) 1989 Andrew W. Appel, David R. Tarditi
2 :			*
3 :			* $Log$
4 :			* Revision 1.1.1.10 1999/04/17 18:56:10 monnier
5 :			* version 110.16
6 :			*
7 :			* Revision 1.1.1.1 1997/01/14 01:38:04 george
8 :			* Version 109.24
9 :			*
10 :			* Revision 1.1.1.1 1996/01/31 16:01:42 george
11 :			* Version 109
12 :			*
13 :			*)
14 :
15 :			structure LrTable : LR_TABLE =
16 :			struct
17 :			open Array List
18 :			infix 9 sub
19 :			datatype ('a,'b) pairlist = EMPTY
20 :			| PAIR of 'a * 'b * ('a,'b) pairlist
21 :			datatype term = T of int
22 :			datatype nonterm = NT of int
23 :			datatype state = STATE of int
24 :			datatype action = SHIFT of state
25 :			| REDUCE of int (* rulenum from grammar *)
26 :			| ACCEPT
27 :			| ERROR
28 :			exception Goto of state * nonterm
29 :			type table = {states: int, rules : int,initialState: state,
30 :			action: ((term,action) pairlist * action) array,
31 :			goto : (nonterm,state) pairlist array}
32 :			val numStates = fn ({states,...} : table) => states
33 :			val numRules = fn ({rules,...} : table) => rules
34 :			val describeActions =
35 :			fn ({action,...} : table) =>
36 :			fn (STATE s) => action sub s
37 :			val describeGoto =
38 :			fn ({goto,...} : table) =>
39 :			fn (STATE s) => goto sub s
40 :			fun findTerm (T term,row,default) =
41 :			let fun find (PAIR (T key,data,r)) =
42 :			if key < term then find r
43 :			else if key=term then data
44 :			else default
45 :			| find EMPTY = default
46 :			in find row
47 :			end
48 :			fun findNonterm (NT nt,row) =
49 :			let fun find (PAIR (NT key,data,r)) =
50 :			if key < nt then find r
51 :			else if key=nt then SOME data
52 :			else NONE
53 :			| find EMPTY = NONE
54 :			in find row
55 :			end
56 :			val action = fn ({action,...} : table) =>
57 :			fn (STATE state,term) =>
58 :			let val (row,default) = action sub state
59 :			in findTerm(term,row,default)
60 :			end
61 :			val goto = fn ({goto,...} : table) =>
62 :			fn (a as (STATE state,nonterm)) =>
63 :			case findNonterm(nonterm,goto sub state)
64 :			of SOME state => state
65 :			| NONE => raise (Goto a)
66 :			val initialState = fn ({initialState,...} : table) => initialState
67 :			val mkLrTable = fn {actions,gotos,initialState,numStates,numRules} =>
68 :			({action=actions,goto=gotos,
69 :			states=numStates,
70 :			rules=numRules,
71 :			initialState=initialState} : table)
72 :			end;

---

root@smlnj-gforge.cs.uchicago.edu	ViewVC Help
Powered by ViewVC 1.0.0