3 # character in column 1 determines outcome...
6 # t is copied as //t if -t is set
7 # other lines are interpreted to call jay procedures
9 .// created by jay 0.7 (c) 1998 Axel.Schreiner@informatik.uni-osnabrueck.de
11 prolog
## %{ ... %} prior to the first %%
14 . /** error output stream.
15 . It should be changeable.
17 . public System
.IO
.TextWriter ErrorOutput
= System
.Console
.Out
;
19 . /** simplified error message.
20 . @see <a href="#yyerror(java.lang.String, java.lang.String[])">yyerror</a>
22 . public void yyerror (string message
) {
23 . yyerror(message
, null);
26 . /** (syntax) error message.
27 . Can be overwritten to control message format.
28 . @param message text to be displayed.
29 . @param expected vector of acceptable tokens, if available.
31 . public void yyerror (string message
, string[] expected
) {
32 . if ((yacc_verbose_flag
> 0) && (expected
!= null) && (expected
.Length
> 0)) {
33 . ErrorOutput
.Write (message
+", expecting");
34 . for (int n
= 0; n
< expected
.Length
; ++ n
)
35 . ErrorOutput
.Write (" "+expected
[n
]);
36 . ErrorOutput
.WriteLine ();
38 . ErrorOutput
.WriteLine (message
);
41 . /** debugging support, requires the package jay.yydebug.
42 . Set to null to suppress debugging messages.
44 t
internal yydebug
.yyDebug debug
;
46 debug
## tables for debugging support
48 . /** index-checked interface to yyNames[].
49 . @param token single character or %token value.
50 . @return token name or [illegal] or [unknown].
52 t
public static string yyname (int token
) {
53 t
if ((token
< 0) || (token
> yyNames
.Length
)) return "[illegal]";
55 t
if ((name
= yyNames
[token
]) != null) return name
;
59 . /** computes list of expected tokens on error by tracing the tables.
60 . @param state for which to compute the list.
61 . @return list of token names.
63 . protected string[] yyExpecting (int state
) {
64 . int token
, n
, len
= 0;
65 . bool[] ok
= new bool[yyNames
.Length
];
67 . if ((n
= yySindex
[state
]) != 0)
68 . for (token
= n
< 0 ? -n
: 0;
69 . (token
< yyNames
.Length
) && (n
+token
< yyTable
.Length
); ++ token
)
70 . if (yyCheck
[n
+token
] == token
&& !ok
[token
] && yyNames
[token
] != null) {
74 . if ((n
= yyRindex
[state
]) != 0)
75 . for (token
= n
< 0 ? -n
: 0;
76 . (token
< yyNames
.Length
) && (n
+token
< yyTable
.Length
); ++ token
)
77 . if (yyCheck
[n
+token
] == token
&& !ok
[token
] && yyNames
[token
] != null) {
82 . string [] result
= new string[len
];
83 . for (n
= token
= 0; n
< len
; ++ token
)
84 . if (ok
[token
]) result
[n
++] = yyNames
[token
];
88 . /** the generated parser, with debugging messages.
89 . Maintains a state and a value stack, currently with fixed maximum size.
90 . @param yyLex scanner.
91 . @param yydebug debug message writer implementing yyDebug, or null.
92 . @return result of the last reduction, if any.
93 . @throws yyException on irrecoverable parse error.
95 . internal Object
yyparse (yyParser
.yyInput yyLex
, Object yyd
)
97 t
this.debug
= (yydebug
.yyDebug
)yyd
;
98 . return yyparse(yyLex
);
101 . /** initial size and increment of the state/value stack [default 256].
102 . This is not final so that it can be overwritten outside of invocations
105 . protected int yyMax
;
107 . /** executed at the beginning of a reduce action.
108 . Used as $$ = yyDefault($1), prior to the user-specified action, if any.
109 . Can be overwritten to provide deep copy, etc.
110 . @param first value for $1, or null.
113 . protected Object
yyDefault (Object first
) {
117 . /** the generated parser.
118 . Maintains a state and a value stack, currently with fixed maximum size.
119 . @param yyLex scanner.
120 . @return result of the last reduction, if any.
121 . @throws yyException on irrecoverable parse error.
123 . internal Object
yyparse (yyParser
.yyInput yyLex
)
125 . if (yyMax
<= 0) yyMax
= 256; // initial size
126 . int yyState
= 0; // state stack ptr
127 . int [] yyStates
= new int[yyMax
]; // state stack
128 . Object yyVal
= null; // value stack ptr
129 . Object
[] yyVals
= new Object
[yyMax
]; // value stack
130 . int yyToken
= -1; // current input
131 . int yyErrorFlag
= 0; // #tks to shift
133 local
## %{ ... %} after the first %%
140 . for (;; ++ yyTop
) {
141 . if (yyTop
>= yyStates
.Length
) { // dynamically increase
142 . int[] i
= new int[yyStates
.Length
+yyMax
];
143 . yyStates
.CopyTo (i
, 0);
145 . Object
[] o
= new Object
[yyVals
.Length
+yyMax
];
146 . yyVals
.CopyTo (o
, 0);
149 . yyStates
[yyTop
] = yyState
;
150 . yyVals
[yyTop
] = yyVal
;
151 t
if (debug
!= null) debug
.push(yyState
, yyVal
);
153 . yyDiscarded
: for (;;) { // discarding a token does not change stack
155 . if ((yyN
= yyDefRed
[yyState
]) == 0) { // else [default] reduce (yyN)
157 . yyToken
= yyLex
.advance() ? yyLex
.token() : 0;
160 t debug
.lex(yyState
, yyToken
, yyname(yyToken
), yyLex
.value());
162 . if ((yyN
= yySindex
[yyState
]) != 0 && ((yyN
+= yyToken
) >= 0)
163 . && (yyN
< yyTable
.Length
) && (yyCheck
[yyN
] == yyToken
)) {
165 t debug
.shift(yyState
, yyTable
[yyN
], yyErrorFlag
-1);
166 . yyState
= yyTable
[yyN
]; // shift to yyN
167 . yyVal
= yyLex
.value();
169 . if (yyErrorFlag
> 0) -- yyErrorFlag
;
172 . if ((yyN
= yyRindex
[yyState
]) != 0 && (yyN
+= yyToken
) >= 0
173 . && yyN
< yyTable
.Length
&& yyCheck
[yyN
] == yyToken
)
174 . yyN
= yyTable
[yyN
]; // reduce (yyN)
176 . switch (yyErrorFlag
) {
179 . yyerror(String
.Format ("syntax error, got token `{0}'", yyname (yyToken
)), yyExpecting(yyState
));
180 t
if (debug
!= null) debug
.error("syntax error");
185 . if ((yyN
= yySindex
[yyStates
[yyTop
]]) != 0
186 . && (yyN
+= Token
.yyErrorCode
) >= 0 && yyN
< yyTable
.Length
187 . && yyCheck
[yyN
] == Token
.yyErrorCode
) {
189 t debug
.shift(yyStates
[yyTop
], yyTable
[yyN
], 3);
190 . yyState
= yyTable
[yyN
];
191 . yyVal
= yyLex
.value();
194 t
if (debug
!= null) debug
.pop(yyStates
[yyTop
]);
195 . } while (-- yyTop
>= 0);
196 t
if (debug
!= null) debug
.reject();
197 . throw new yyParser
.yyException("irrecoverable syntax error");
200 . if (yyToken
== 0) {
201 t
if (debug
!= null) debug
.reject();
202 . throw new yyParser
.yyException("irrecoverable syntax error at end-of-file");
205 t debug
.discard(yyState
, yyToken
, yyname(yyToken
),
208 . goto yyDiscarded
; // leave stack alone
211 . int yyV
= yyTop
+ 1-yyLen
[yyN
];
213 t debug
.reduce(yyState
, yyStates
[yyV
-1], yyN
, yyRule
[yyN
], yyLen
[yyN
]);
214 . yyVal
= yyDefault(yyV
> yyTop
? null : yyVals
[yyV
]);
217 actions
## code from the actions within the grammar
220 . yyTop
-= yyLen
[yyN
];
221 . yyState
= yyStates
[yyTop
];
222 . int yyM
= yyLhs
[yyN
];
223 . if (yyState
== 0 && yyM
== 0) {
224 t
if (debug
!= null) debug
.shift(0, yyFinal
);
227 . yyToken
= yyLex
.advance() ? yyLex
.token() : 0;
230 t debug
.lex(yyState
, yyToken
,yyname(yyToken
), yyLex
.value());
232 . if (yyToken
== 0) {
233 t
if (debug
!= null) debug
.accept(yyVal
);
238 . if (((yyN
= yyGindex
[yyM
]) != 0) && ((yyN
+= yyState
) >= 0)
239 . && (yyN
< yyTable
.Length
) && (yyCheck
[yyN
] == yyState
))
240 . yyState
= yyTable
[yyN
];
242 . yyState
= yyDgoto
[yyM
];
243 t
if (debug
!= null) debug
.shift(yyStates
[yyTop
], yyState
);
249 tables
## tables for rules, default reduction, and action calls
251 epilog
## text following second %%
254 . internal interface yyDebug
{
255 . void push (int state
, Object
value);
256 . void lex (int state
, int token
, string name
, Object
value);
257 . void shift (int from, int to
, int errorFlag
);
258 . void pop (int state
);
259 . void discard (int state
, int token
, string name
, Object
value);
260 . void reduce (int from, int to
, int rule
, string text
, int len
);
261 . void shift (int from, int to
);
262 . void accept (Object
value);
263 . void error (string message
);
267 . class yyDebugSimple
: yyDebug
{
268 . void println (string s
){
269 . Console
.Error
.WriteLine (s
);
272 . public void push (int state
, Object
value) {
273 . println ("push\tstate "+state
+"\tvalue "+value);
276 . public void lex (int state
, int token
, string name
, Object
value) {
277 . println("lex\tstate "+state
+"\treading "+name
+"\tvalue "+value);
280 . public void shift (int from, int to
, int errorFlag
) {
281 . switch (errorFlag
) {
282 . default: // normally
283 . println("shift\tfrom state "+from+" to "+to
);
285 . case 0: case 1: case 2: // in error recovery
286 . println("shift\tfrom state "+from+" to "+to
287 . +"\t"+errorFlag
+" left to recover");
289 . case 3: // normally
290 . println("shift\tfrom state "+from+" to "+to
+"\ton error");
295 . public void pop (int state
) {
296 . println("pop\tstate "+state
+"\ton error");
299 . public void discard (int state
, int token
, string name
, Object
value) {
300 . println("discard\tstate "+state
+"\ttoken "+name
+"\tvalue "+value);
303 . public void reduce (int from, int to
, int rule
, string text
, int len
) {
304 . println("reduce\tstate "+from+"\tuncover "+to
305 . +"\trule ("+rule
+") "+text
);
308 . public void shift (int from, int to
) {
309 . println("goto\tfrom state "+from+" to "+to
);
312 . public void accept (Object
value) {
313 . println("accept\tvalue "+value);
316 . public void error (string message
) {
317 . println("error\t"+message
);
320 . public void reject () {
328 tokens
public const int
330 . namespace yyParser
{
332 . /** thrown for irrecoverable syntax errors and stack overflow.
334 . internal class yyException
: System
.Exception
{
335 . public yyException (string message
) : base (message
) {
339 . /** must be implemented by a scanner object to supply input to the parser.
341 . internal interface yyInput
{
342 . /** move on to next token.
343 . @return false if positioned beyond tokens.
344 . @throws IOException on input error.
346 . bool advance (); // throws java.io.IOException;
347 . /** classifies current token.
348 . Should not be called if advance() returned false.
349 . @return current %token or single character.
352 . /** associated with current token.
353 . Should not be called if advance() returned false.
354 . @return value for token().
359 .} // close outermost namespace, that MUST HAVE BEEN opened in the prolog