org.antlr.runtime.debug
Class DebugTokenStream
java.lang.Object
org.antlr.runtime.debug.DebugTokenStream
- All Implemented Interfaces:
- IntStream, TokenStream
public class DebugTokenStream
- extends java.lang.Object
- implements TokenStream
Method Summary |
void |
consume()
|
protected void |
consumeInitialHiddenTokens()
|
Token |
get(int i)
Get a token at an absolute index i; 0..n-1. |
java.lang.String |
getSourceName()
Where are you getting symbols from? Normally, implementations will
pass the buck all the way to the lexer who can ask its input stream
for the file name or whatever. |
TokenSource |
getTokenSource()
Where is this stream pulling tokens from? This is not the name, but
the object that provides Token objects. |
int |
index()
Return the current input symbol index 0..n where n indicates the
last symbol has been read. |
int |
LA(int i)
Get int at current input pointer + i ahead where i=1 is next int. |
Token |
LT(int i)
Get Token at current input pointer + i ahead where i=1 is next Token. |
int |
mark()
Tell the stream to start buffering if it hasn't already. |
void |
release(int marker)
You may want to commit to a backtrack but don't want to force the
stream to keep bookkeeping objects around for a marker that is
no longer necessary. |
void |
rewind()
Rewind to the input position of the last marker. |
void |
rewind(int marker)
Reset the stream so that next call to index would return marker. |
void |
seek(int index)
Set the input cursor to the position indicated by index. |
void |
setDebugListener(DebugEventListener dbg)
|
int |
size()
Only makes sense for streams that buffer everything up probably, but
might be useful to display the entire stream or for testing. |
java.lang.String |
toString()
|
java.lang.String |
toString(int start,
int stop)
Return the text of all tokens from start to stop, inclusive. |
java.lang.String |
toString(Token start,
Token stop)
Because the user is not required to use a token with an index stored
in it, we must provide a means for two token objects themselves to
indicate the start/end location. |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
dbg
protected DebugEventListener dbg
input
public TokenStream input
initialStreamState
protected boolean initialStreamState
lastMarker
protected int lastMarker
- Track the last mark() call result value for use in rewind().
DebugTokenStream
public DebugTokenStream(TokenStream input,
DebugEventListener dbg)
setDebugListener
public void setDebugListener(DebugEventListener dbg)
consume
public void consume()
- Specified by:
consume
in interface IntStream
consumeInitialHiddenTokens
protected void consumeInitialHiddenTokens()
LT
public Token LT(int i)
- Description copied from interface:
TokenStream
- Get Token at current input pointer + i ahead where i=1 is next Token.
i<0 indicates tokens in the past. So -1 is previous token and -2 is
two tokens ago. LT(0) is undefined. For i>=n, return Token.EOFToken.
Return null for LT(0) and any index that results in an absolute address
that is negative.
- Specified by:
LT
in interface TokenStream
LA
public int LA(int i)
- Description copied from interface:
IntStream
- Get int at current input pointer + i ahead where i=1 is next int.
Negative indexes are allowed. LA(-1) is previous token (token
just matched). LA(-i) where i is before first token should
yield -1, invalid char / EOF.
- Specified by:
LA
in interface IntStream
get
public Token get(int i)
- Description copied from interface:
TokenStream
- Get a token at an absolute index i; 0..n-1. This is really only
needed for profiling and debugging and token stream rewriting.
If you don't want to buffer up tokens, then this method makes no
sense for you. Naturally you can't use the rewrite stream feature.
I believe DebugTokenStream can easily be altered to not use
this method, removing the dependency.
- Specified by:
get
in interface TokenStream
mark
public int mark()
- Description copied from interface:
IntStream
- Tell the stream to start buffering if it hasn't already. Return
current input position, index(), or some other marker so that
when passed to rewind() you get back to the same spot.
rewind(mark()) should not affect the input cursor. The Lexer
track line/col info as well as input index so its markers are
not pure input indexes. Same for tree node streams.
- Specified by:
mark
in interface IntStream
index
public int index()
- Description copied from interface:
IntStream
- Return the current input symbol index 0..n where n indicates the
last symbol has been read. The index is the symbol about to be
read not the most recently read symbol.
- Specified by:
index
in interface IntStream
rewind
public void rewind(int marker)
- Description copied from interface:
IntStream
- Reset the stream so that next call to index would return marker.
The marker will usually be index() but it doesn't have to be. It's
just a marker to indicate what state the stream was in. This is
essentially calling release() and seek(). If there are markers
created after this marker argument, this routine must unroll them
like a stack. Assume the state the stream was in when this marker
was created.
- Specified by:
rewind
in interface IntStream
rewind
public void rewind()
- Description copied from interface:
IntStream
- 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. It is
like invoking rewind(last marker) but it should not "pop"
the marker off. It's like seek(last marker's input position).
- Specified by:
rewind
in interface IntStream
release
public void release(int marker)
- Description copied from interface:
IntStream
- You may want to commit to a backtrack but don't want to force the
stream to keep bookkeeping objects around for a marker that is
no longer necessary. This will have the same behavior as
rewind() except it releases resources without the backward seek.
This must throw away resources for all markers back to the marker
argument. So if you're nested 5 levels of mark(), and then release(2)
you have to release resources for depths 2..5.
- Specified by:
release
in interface IntStream
seek
public void seek(int index)
- Description copied from interface:
IntStream
- Set the input cursor to the position indicated by index. This is
normally used to seek ahead in the input stream. No buffering is
required to do this unless you know your stream will use seek to
move backwards such as when backtracking.
This is different from rewind in its multi-directional
requirement and in that its argument is strictly an input cursor (index).
For char streams, seeking forward must update the stream state such
as line number. For seeking backwards, you will be presumably
backtracking using the mark/rewind mechanism that restores state and
so this method does not need to update state when seeking backwards.
Currently, this method is only used for efficient backtracking using
memoization, but in the future it may be used for incremental parsing.
The index is 0..n-1. A seek to position i means that LA(1) will
return the ith symbol. So, seeking to 0 means LA(1) will return the
first element in the stream.
- Specified by:
seek
in interface IntStream
size
public int size()
- Description copied from interface:
IntStream
- Only makes sense for streams that buffer everything up probably, but
might be useful to display the entire stream or for testing. This
value includes a single EOF.
- Specified by:
size
in interface IntStream
getTokenSource
public TokenSource getTokenSource()
- Description copied from interface:
TokenStream
- Where is this stream pulling tokens from? This is not the name, but
the object that provides Token objects.
- Specified by:
getTokenSource
in interface TokenStream
getSourceName
public java.lang.String getSourceName()
- Description copied from interface:
IntStream
- Where are you getting symbols from? Normally, implementations will
pass the buck all the way to the lexer who can ask its input stream
for the file name or whatever.
- Specified by:
getSourceName
in interface IntStream
toString
public java.lang.String toString()
- Overrides:
toString
in class java.lang.Object
toString
public java.lang.String toString(int start,
int stop)
- Description copied from interface:
TokenStream
- Return the text of all tokens from start to stop, inclusive.
If the stream does not buffer all the tokens then it can just
return "" or null; Users should not access $ruleLabel.text in
an action of course in that case.
- Specified by:
toString
in interface TokenStream
toString
public java.lang.String toString(Token start,
Token stop)
- Description copied from interface:
TokenStream
- Because the user is not required to use a token with an index stored
in it, we must provide a means for two token objects themselves to
indicate the start/end location. Most often this will just delegate
to the other toString(int,int). This is also parallel with
the TreeNodeStream.toString(Object,Object).
- Specified by:
toString
in interface TokenStream
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