java.lang.Object antlr.TokenStreamRewriteEngine
This token stream tracks the *entire* token stream coming from a lexer, but does not pass on the whitespace (or whatever else you want to discard) to the parser. This class can then be asked for the ith token in the input stream. Useful for dumping out the input stream exactly after doing some augmentation or other manipulations. Tokens are index from 0..n-1 You can insert stuff, replace, and delete chunks. Note that the operations are done lazily--only if you convert the buffer to a String. This is very efficient because you are not moving data around all the time. As the buffer of tokens is converted to strings, the toString() method(s) check to see if there is an operation at the current index. If so, the operation is done and then normal String rendering continues on the buffer. This is like having multiple Turing machine instruction streams (programs) operating on a single input tape. :) Since the operations are done lazily at toString-time, operations do not screw up the token index values. That is, an insert operation at token index i does not change the index values for tokens i+1..n-1. Because operations never actually alter the buffer, you may always get the original token stream back without undoing anything. Since the instructions are queued up, you can easily simulate transactions and roll back any changes if there is an error just by removing instructions. For example, TokenStreamRewriteEngine rewriteEngine = new TokenStreamRewriteEngine(lexer); JavaRecognizer parser = new JavaRecognizer(rewriteEngine); ... rewriteEngine.insertAfter("pass1", t, "foobar");} rewriteEngine.insertAfter("pass2", u, "start");} System.out.println(rewriteEngine.toString("pass1")); System.out.println(rewriteEngine.toString("pass2")); You can also have multiple "instruction streams" and get multiple rewrites from a single pass over the input. Just name the instruction streams and use that name again when printing the buffer. This could be useful for generating a C file and also its header file--all from the same buffer. If you don't use named rewrite streams, a "default" stream is used. Terence Parr, parrt@cs.usfca.edu University of San Francisco February 2004
Field Summary | |
static java.lang.String |
DEFAULT_PROGRAM_NAME
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static int |
MIN_TOKEN_INDEX
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static int |
PROGRAM_INIT_SIZE
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Constructor Summary | |
TokenStreamRewriteEngine(TokenStream upstream)
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TokenStreamRewriteEngine(TokenStream upstream,
int initialSize)
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Method Summary | |
void |
delete(int index)
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void |
delete(int from,
int to)
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void |
delete(java.lang.String programName,
int from,
int to)
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void |
delete(java.lang.String programName,
Token from,
Token to)
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void |
delete(Token indexT)
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void |
delete(Token from,
Token to)
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void |
deleteProgram()
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void |
deleteProgram(java.lang.String programName)
Reset the program so that no instructions exist |
void |
discard(int ttype)
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int |
getLastRewriteTokenIndex()
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TokenWithIndex |
getToken(int i)
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int |
getTokenStreamSize()
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void |
insertAfter(int index,
java.lang.String text)
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void |
insertAfter(java.lang.String programName,
int index,
java.lang.String text)
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void |
insertAfter(java.lang.String programName,
Token t,
java.lang.String text)
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void |
insertAfter(Token t,
java.lang.String text)
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void |
insertBefore(int index,
java.lang.String text)
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void |
insertBefore(java.lang.String programName,
int index,
java.lang.String text)
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void |
insertBefore(java.lang.String programName,
Token t,
java.lang.String text)
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void |
insertBefore(Token t,
java.lang.String text)
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Token |
nextToken()
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void |
replace(int from,
int to,
java.lang.String text)
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void |
replace(int index,
java.lang.String text)
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void |
replace(java.lang.String programName,
int from,
int to,
java.lang.String text)
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void |
replace(java.lang.String programName,
Token from,
Token to,
java.lang.String text)
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void |
replace(Token indexT,
java.lang.String text)
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void |
replace(Token from,
Token to,
java.lang.String text)
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void |
rollback(int instructionIndex)
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void |
rollback(java.lang.String programName,
int instructionIndex)
Rollback the instruction stream for a program so that the indicated instruction (via instructionIndex) is no longer in the stream. |
java.lang.String |
toDebugString()
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java.lang.String |
toDebugString(int start,
int end)
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java.lang.String |
toOriginalString()
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java.lang.String |
toOriginalString(int start,
int end)
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java.lang.String |
toString()
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java.lang.String |
toString(int start,
int end)
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java.lang.String |
toString(java.lang.String programName)
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java.lang.String |
toString(java.lang.String programName,
int start,
int end)
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Methods inherited from class java.lang.Object |
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Field Detail |
public static final int MIN_TOKEN_INDEX
public static final java.lang.String DEFAULT_PROGRAM_NAME
public static final int PROGRAM_INIT_SIZE
Constructor Detail |
public TokenStreamRewriteEngine(TokenStream upstream)
public TokenStreamRewriteEngine(TokenStream upstream, int initialSize)
Method Detail |
public Token nextToken() throws TokenStreamException
nextToken
in interface TokenStream
TokenStreamException
public void rollback(int instructionIndex)
public void rollback(java.lang.String programName, int instructionIndex)
public void deleteProgram()
public void deleteProgram(java.lang.String programName)
public void insertAfter(Token t, java.lang.String text)
public void insertAfter(int index, java.lang.String text)
public void insertAfter(java.lang.String programName, Token t, java.lang.String text)
public void insertAfter(java.lang.String programName, int index, java.lang.String text)
public void insertBefore(Token t, java.lang.String text)
public void insertBefore(int index, java.lang.String text)
public void insertBefore(java.lang.String programName, Token t, java.lang.String text)
public void insertBefore(java.lang.String programName, int index, java.lang.String text)
public void replace(int index, java.lang.String text)
public void replace(int from, int to, java.lang.String text)
public void replace(Token indexT, java.lang.String text)
public void replace(Token from, Token to, java.lang.String text)
public void replace(java.lang.String programName, int from, int to, java.lang.String text)
public void replace(java.lang.String programName, Token from, Token to, java.lang.String text)
public void delete(int index)
public void delete(int from, int to)
public void delete(Token indexT)
public void delete(Token from, Token to)
public void delete(java.lang.String programName, int from, int to)
public void delete(java.lang.String programName, Token from, Token to)
public void discard(int ttype)
public TokenWithIndex getToken(int i)
public int getTokenStreamSize()
public java.lang.String toOriginalString()
public java.lang.String toOriginalString(int start, int end)
public java.lang.String toString()
public java.lang.String toString(java.lang.String programName)
public java.lang.String toString(int start, int end)
public java.lang.String toString(java.lang.String programName, int start, int end)
public java.lang.String toDebugString()
public java.lang.String toDebugString(int start, int end)
public int getLastRewriteTokenIndex()