Package org.antlr.runtime

Class LegacyCommonTokenStream

  • All Implemented Interfaces:
    IntStream, TokenStream
    public class LegacyCommonTokenStream
extends Object
implements TokenStream
    The most common stream of tokens is one where every token is buffered up and tokens are prefiltered for a certain channel (the parser will only see these tokens and cannot change the filter channel number during the parse). TODO: how to access the full token stream? How to track all tokens matched per rule?

    • Field Summary

      Fields 
      Modifier and Type Field Description
      protected int channel
      Skip tokens on any channel but this one; this is how we skip whitespace...
      protected Map<Integer,​Integer> channelOverrideMap
      Map<tokentype, channel> to override some Tokens' channel numbers
      protected boolean discardOffChannelTokens
      By default, track all incoming tokens
      protected Set<Integer> discardSet
      Set<tokentype>; discard any tokens with this type
      protected int lastMarker
      Track the last mark() call result value for use in rewind().
      protected int p
      The index into the tokens list of the current token (next token to consume).
      protected int range  
      protected List<Token> tokens
      Record every single token pulled from the source so we can reproduce chunks of it later.
      protected TokenSource tokenSource  

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void consume()
      Move the input pointer to the next incoming token.
      void discardOffChannelTokens​(boolean discardOffChannelTokens)  
      void discardTokenType​(int ttype)  
      protected void fillBuffer()
      Load all tokens from the token source and put in tokens.
      Token get​(int i)
      Return absolute token i; ignore which channel the tokens are on; that is, count all tokens not just on-channel tokens.
      List<? extends Token> get​(int start, int stop)
      Get all tokens from start..stop inclusively
      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.
      List<? extends Token> getTokens()  
      List<? extends Token> getTokens​(int start, int stop)  
      List<? extends Token> getTokens​(int start, int stop, int ttype)  
      List<? extends Token> getTokens​(int start, int stop, List<Integer> types)  
      List<? extends Token> getTokens​(int start, int stop, BitSet types)
      Given a start and stop index, return a List of all tokens in the token type BitSet.
      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.
      protected Token LB​(int k)
      Look backwards k tokens on-channel tokens
      Token LT​(int k)
      Get the ith token from the current position 1..n where k=1 is the first symbol of lookahead.
      int mark()
      Tell the stream to start buffering if it hasn't already.
      int range()
      How far ahead has the stream been asked to look? The return value is a valid index from 0..n-1.
      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 reset()  
      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 setTokenSource​(TokenSource tokenSource)
      Reset this token stream by setting its token source.
      void setTokenTypeChannel​(int ttype, int channel)
      A simple filter mechanism whereby you can tell this token stream to force all tokens of type ttype to be on channel.
      int size()
      Only makes sense for streams that buffer everything up probably, but might be useful to display the entire stream or for testing.
      protected int skipOffTokenChannels​(int i)
      Given a starting index, return the index of the first on-channel token.
      protected int skipOffTokenChannelsReverse​(int i)  
      String toString()  
      String toString​(int start, int stop)
      Return the text of all tokens from start to stop, inclusive.
      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.

    • Field Detail

      • tokens

        protected List<Token> tokens
        Record every single token pulled from the source so we can reproduce chunks of it later.

      • channelOverrideMap

        protected Map<Integer,​Integer> channelOverrideMap
        Map<tokentype, channel> to override some Tokens' channel numbers

      • discardSet

        protected Set<Integer> discardSet
        Set<tokentype>; discard any tokens with this type

      • channel

        protected int channel
        Skip tokens on any channel but this one; this is how we skip whitespace...

      • discardOffChannelTokens

        protected boolean discardOffChannelTokens
        By default, track all incoming tokens

      • lastMarker

        protected int lastMarker
        Track the last mark() call result value for use in rewind().

      • range

        protected int range

      • p

        protected int p
        The index into the tokens list of the current token (next token to consume). p==-1 indicates that the tokens list is empty

    • Constructor Detail

      • LegacyCommonTokenStream

        public LegacyCommonTokenStream()

      • LegacyCommonTokenStream

        public LegacyCommonTokenStream​(TokenSource tokenSource)

      • LegacyCommonTokenStream

        public LegacyCommonTokenStream​(TokenSource tokenSource,
                               int channel)

    • Method Detail

      • setTokenSource

        public void setTokenSource​(TokenSource tokenSource)
        Reset this token stream by setting its token source.

      • fillBuffer

        protected void fillBuffer()
        Load all tokens from the token source and put in tokens. This is done upon first LT request because you might want to set some token type / channel overrides before filling buffer.

      • consume

        public void consume()
        Move the input pointer to the next incoming token. The stream must become active with LT(1) available. consume() simply moves the input pointer so that LT(1) points at the next input symbol. Consume at least one token. Walk past any token not on the channel the parser is listening to.
        Specified by:
        consume in interface IntStream

      • skipOffTokenChannels

        protected int skipOffTokenChannels​(int i)
        Given a starting index, return the index of the first on-channel token.

      • skipOffTokenChannelsReverse

        protected int skipOffTokenChannelsReverse​(int i)

      • setTokenTypeChannel

        public void setTokenTypeChannel​(int ttype,
                                int channel)
        A simple filter mechanism whereby you can tell this token stream to force all tokens of type ttype to be on channel. For example, when interpreting, we cannot exec actions so we need to tell the stream to force all WS and NEWLINE to be a different, ignored channel.

      • discardTokenType

        public void discardTokenType​(int ttype)

      • discardOffChannelTokens

        public void discardOffChannelTokens​(boolean discardOffChannelTokens)

      • getTokens

        public List<? extends Token> getTokens()

      • getTokens

        public List<? extends Token> getTokens​(int start,
                                       int stop)

      • getTokens

        public List<? extends Token> getTokens​(int start,
                                       int stop,
                                       BitSet types)
        Given a start and stop index, return a List of all tokens in the token type BitSet. Return null if no tokens were found. This method looks at both on and off channel tokens.

      • getTokens

        public List<? extends Token> getTokens​(int start,
                                       int stop,
                                       List<Integer> types)

      • getTokens

        public List<? extends Token> getTokens​(int start,
                                       int stop,
                                       int ttype)

      • LT

        public Token LT​(int k)
        Get the ith token from the current position 1..n where k=1 is the first symbol of lookahead.
        Specified by:
        LT in interface TokenStream

      • LB

        protected Token LB​(int k)
        Look backwards k tokens on-channel tokens

      • get

        public Token get​(int i)
        Return absolute token i; ignore which channel the tokens are on; that is, count all tokens not just on-channel tokens.
        Specified by:
        get in interface TokenStream

      • get

        public List<? extends Token> get​(int start,
                                 int stop)
        Get all tokens from start..stop inclusively

      • 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

      • 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

      • 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

      • 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

      • 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

      • range

        public int range()
        Description copied from interface: TokenStream
        How far ahead has the stream been asked to look? The return value is a valid index from 0..n-1.
        Specified by:
        range in interface TokenStream

      • 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

      • reset

        public void reset()

      • 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

      • 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 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 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 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