| org.antlr.runtime.debug.DebugEventListener
All known Subclasses: org.antlr.runtime.debug.DebugEventRepeater, org.antlr.runtime.debug.DebugEventHub, org.antlr.runtime.debug.BlankDebugEventListener,
| DebugEventListener | | public interface DebugEventListener (Code) | | All debugging events that a recognizer can trigger.
I did not create a separate AST debugging interface as it would create
lots of extra classes and DebugParser has a dbg var defined, which makes
it hard to change to ASTDebugEventListener. I looked hard at this issue
and it is easier to understand as one monolithic event interface for all
possible events. Hopefully, adding ST debugging stuff won't be bad. Leave
for future. 4/26/2006.
|
| Method Summary | |
| public void | LT(int i, Token t)
Somebody (anybody) looked ahead. | | public void | LT(int i, Object t)
The tree parser lookedahead. | | public void | addChild(Object root, Object child)
Make childID a child of rootID. | | public void | becomeRoot(Object newRoot, Object oldRoot)
Make a node the new root of an existing root. | | public void | beginBacktrack(int level)
| | public void | beginResync()
Indicates the recognizer is about to consume tokens to resynchronize
the parser. | | public void | commence()
Announce that parsing has begun. | | public void | consumeHiddenToken(Token t)
An off-channel input token was consumed. | | public void | consumeNode(Object t)
Input for a tree parser is an AST, but we know nothing for sure
about a node except its type and text (obtained from the adaptor).
This is the analog of the consumeToken method. | | public void | consumeToken(Token t)
An input token was consumed; matched by any kind of element. | | public void | createNode(Object t)
Announce a new node built from token elements such as type etc... | | public void | createNode(Object node, Token token)
Announce a new node built from an existing token. | | public void | endBacktrack(int level, boolean successful)
| | public void | endResync()
Indicates that the recognizer has finished consuming tokens in order
to resychronize. | | public void | enterAlt(int alt)
Because rules can have lots of alternatives, it is very useful to
know which alt you are entering. | | public void | enterDecision(int decisionNumber)
Every decision, fixed k or arbitrary, has an enter/exit event
so that a GUI can easily track what LT/consume events are
associated with prediction. | | public void | enterRule(String ruleName)
The parser has just entered a rule. | | public void | enterSubRule(int decisionNumber)
| | public void | exitDecision(int decisionNumber)
| | public void | exitRule(String ruleName)
This is the last thing executed before leaving a rule. | | public void | exitSubRule(int decisionNumber)
| | public void | location(int line, int pos)
To watch a parser move through the grammar, the parser needs to
inform the debugger what line/charPos it is passing in the grammar. | | public void | mark(int marker)
The parser is going to look arbitrarily ahead; mark this location,
the token stream's marker is sent in case you need it. | | public void | nilNode(Object t)
A nil was created (even nil nodes have a unique ID...
they are not "null" per se). | | public void | recognitionException(RecognitionException e)
A recognition exception occurred such as NoViableAltException. | | public void | rewind(int marker)
After an arbitrairly long lookahead as with a cyclic DFA (or with
any backtrack), this informs the debugger that stream should be
rewound to the position associated with marker. | | public void | rewind()
Rewind to the input position of the last marker.
Used currently only after a cyclic DFA and just
before starting a sem/syn predicate to get the
input position back to the start of the decision.
Do not "pop" the marker off the state. | | public void | semanticPredicate(boolean result, String predicate)
| | public void | setTokenBoundaries(Object t, int tokenStartIndex, int tokenStopIndex)
Set the token start/stop token index for a subtree root or node. | | public void | terminate()
Parsing is over; successfully or not. |
| FALSE | | final public static int FALSE(Code) | | |
| PROTOCOL_VERSION | | final public static String PROTOCOL_VERSION(Code) | | |
| TRUE | | final public static int TRUE(Code) | | serialized version of true
|
| LT | | public void LT(int i, Token t)(Code) | | Somebody (anybody) looked ahead. Note that this actually gets
triggered by both LA and LT calls. The debugger will want to know
which Token object was examined. Like consumeToken, this indicates
what token was seen at that depth. A remote debugger cannot look
ahead into a file it doesn't have so LT events must pass the token
even if the info is redundant.
|
| LT | | public void LT(int i, Object t)(Code) | | The tree parser lookedahead. If the type is UP or DOWN,
then the ID is not really meaningful as it's fixed--there is
just one UP node and one DOWN navigation node.
|
| addChild | | public void addChild(Object root, Object child)(Code) | | Make childID a child of rootID.
If you are receiving this event over a socket via
RemoteDebugEventSocketListener then only IDs are set.
See Also: org.antlr.runtime.tree.TreeAdaptor.addChild() |
| becomeRoot | | public void becomeRoot(Object newRoot, Object oldRoot)(Code) | | Make a node the new root of an existing root. See
Note: the newRootID parameter is possibly different
than the TreeAdaptor.becomeRoot() newRoot parameter.
In our case, it will always be the result of calling
TreeAdaptor.becomeRoot() and not root_n or whatever.
The listener should assume that this event occurs
only when the current subrule (or rule) subtree is
being reset to newRootID.
If you are receiving this event over a socket via
RemoteDebugEventSocketListener then only IDs are set.
See Also: org.antlr.runtime.tree.TreeAdaptor.becomeRoot() |
| beginBacktrack | | public void beginBacktrack(int level)(Code) | | |
| beginResync | | public void beginResync()(Code) | | Indicates the recognizer is about to consume tokens to resynchronize
the parser. Any consume events from here until the recovered event
are not part of the parse--they are dead tokens.
|
| commence | | public void commence()(Code) | | Announce that parsing has begun. Not technically useful except for
sending events over a socket. A GUI for example will launch a thread
to connect and communicate with a remote parser. The thread will want
to notify the GUI when a connection is made. ANTLR parsers
trigger this upon entry to the first rule (the ruleLevel is used to
figure this out).
|
| consumeHiddenToken | | public void consumeHiddenToken(Token t)(Code) | | An off-channel input token was consumed.
Trigger after the token was matched by things like match(), matchAny().
(unless of course the hidden token is first stuff in the input stream).
|
| consumeNode | | public void consumeNode(Object t)(Code) | | Input for a tree parser is an AST, but we know nothing for sure
about a node except its type and text (obtained from the adaptor).
This is the analog of the consumeToken method. Again, the ID is
the hashCode usually of the node so it only works if hashCode is
not implemented. If the type is UP or DOWN, then
the ID is not really meaningful as it's fixed--there is
just one UP node and one DOWN navigation node.
Parameters:
t - |
| consumeToken | | public void consumeToken(Token t)(Code) | | An input token was consumed; matched by any kind of element.
Trigger after the token was matched by things like match(), matchAny().
|
| createNode | | public void createNode(Object t)(Code) | | Announce a new node built from token elements such as type etc...
If you are receiving this event over a socket via
RemoteDebugEventSocketListener then only t.ID, type, text are
set.
|
| createNode | | public void createNode(Object node, Token token)(Code) | | Announce a new node built from an existing token.
If you are receiving this event over a socket via
RemoteDebugEventSocketListener then only node.ID and token.tokenIndex
are set.
|
| endBacktrack | | public void endBacktrack(int level, boolean successful)(Code) | | |
| endResync | | public void endResync()(Code) | | Indicates that the recognizer has finished consuming tokens in order
to resychronize. There may be multiple beginResync/endResync pairs
before the recognizer comes out of errorRecovery mode (in which
multiple errors are suppressed). This will be useful
in a gui where you want to probably grey out tokens that are consumed
but not matched to anything in grammar. Anything between
a beginResync/endResync pair was tossed out by the parser.
|
| enterAlt | | public void enterAlt(int alt)(Code) | | Because rules can have lots of alternatives, it is very useful to
know which alt you are entering. This is 1..n for n alts.
|
| enterDecision | | public void enterDecision(int decisionNumber)(Code) | | Every decision, fixed k or arbitrary, has an enter/exit event
so that a GUI can easily track what LT/consume events are
associated with prediction. You will see a single enter/exit
subrule but multiple enter/exit decision events, one for each
loop iteration.
|
| enterRule | | public void enterRule(String ruleName)(Code) | | The parser has just entered a rule. No decision has been made about
which alt is predicted. This is fired AFTER init actions have been
executed. Attributes are defined and available etc...
|
| enterSubRule | | public void enterSubRule(int decisionNumber)(Code) | | Track entry into any (...) subrule other EBNF construct
|
| exitDecision | | public void exitDecision(int decisionNumber)(Code) | | |
| exitRule | | public void exitRule(String ruleName)(Code) | | This is the last thing executed before leaving a rule. It is
executed even if an exception is thrown. This is triggered after
error reporting and recovery have occurred (unless the exception is
not caught in this rule). This implies an "exitAlt" event.
|
| exitSubRule | | public void exitSubRule(int decisionNumber)(Code) | | |
| location | | public void location(int line, int pos)(Code) | | To watch a parser move through the grammar, the parser needs to
inform the debugger what line/charPos it is passing in the grammar.
For now, this does not know how to switch from one grammar to the
other and back for island grammars etc...
This should also allow breakpoints because the debugger can stop
the parser whenever it hits this line/pos.
|
| mark | | public void mark(int marker)(Code) | | The parser is going to look arbitrarily ahead; mark this location,
the token stream's marker is sent in case you need it.
|
| nilNode | | public void nilNode(Object t)(Code) | | A nil was created (even nil nodes have a unique ID...
they are not "null" per se). As of 4/28/2006, this
seems to be uniquely triggered when starting a new subtree
such as when entering a subrule in automatic mode and when
building a tree in rewrite mode.
If you are receiving this event over a socket via
RemoteDebugEventSocketListener then only t.ID is set.
|
| recognitionException | | public void recognitionException(RecognitionException e)(Code) | | A recognition exception occurred such as NoViableAltException. I made
this a generic event so that I can alter the exception hierachy later
without having to alter all the debug objects.
Upon error, the stack of enter rule/subrule must be properly unwound.
If no viable alt occurs it is within an enter/exit decision, which
also must be rewound. Even the rewind for each mark must be unwount.
In the Java target this is pretty easy using try/finally, if a bit
ugly in the generated code. The rewind is generated in DFA.predict()
actually so no code needs to be generated for that. For languages
w/o this "finally" feature (C++?), the target implementor will have
to build an event stack or something.
Across a socket for remote debugging, only the RecognitionException
data fields are transmitted. The token object or whatever that
caused the problem was the last object referenced by LT. The
immediately preceding LT event should hold the unexpected Token or
char.
Here is a sample event trace for grammar:
b : C ({;}A|B) // {;} is there to prevent A|B becoming a set
| D
;
The sequence for this rule (with no viable alt in the subrule) for
input 'c c' (there are 3 tokens) is:
commence
LT(1)
enterRule b
location 7 1
enter decision 3
LT(1)
exit decision 3
enterAlt1
location 7 5
LT(1)
consumeToken [c/<4>,1:0]
location 7 7
enterSubRule 2
enter decision 2
LT(1)
LT(1)
recognitionException NoViableAltException 2 1 2
exit decision 2
exitSubRule 2
beginResync
LT(1)
consumeToken [c/<4>,1:1]
LT(1)
endResync
LT(-1)
exitRule b
terminate
|
| rewind | | public void rewind(int marker)(Code) | | After an arbitrairly long lookahead as with a cyclic DFA (or with
any backtrack), this informs the debugger that stream should be
rewound to the position associated with marker.
|
| rewind | | public void rewind()(Code) | | Rewind to the input position of the last marker.
Used currently only after a cyclic DFA and just
before starting a sem/syn predicate to get the
input position back to the start of the decision.
Do not "pop" the marker off the state. mark(i)
and rewind(i) should balance still.
|
| semanticPredicate | | public void semanticPredicate(boolean result, String predicate)(Code) | | A semantic predicate was evaluate with this result and action text
|
| setTokenBoundaries | | public void setTokenBoundaries(Object t, int tokenStartIndex, int tokenStopIndex)(Code) | | Set the token start/stop token index for a subtree root or node.
If you are receiving this event over a socket via
RemoteDebugEventSocketListener then only t.ID is set.
|
| terminate | | public void terminate()(Code) | | Parsing is over; successfully or not. Mostly useful for telling
remote debugging listeners that it's time to quit. When the rule
invocation level goes to zero at the end of a rule, we are done
parsing.
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