antlr

Class TokenStreamRewriteEngine

public class TokenStreamRewriteEngine extends Object implements TokenStream, IASDebugStream

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 at antlr.org University of San Francisco February 2004
Nested Class Summary
static classTokenStreamRewriteEngine.DeleteOp
static classTokenStreamRewriteEngine.InsertBeforeOp
static classTokenStreamRewriteEngine.ReplaceOp
I'm going to try replacing range from x..y with (y-x)+1 ReplaceOp instructions.
static classTokenStreamRewriteEngine.RewriteOperation
Field Summary
protected BitSetdiscardMask
Which (whitespace) token(s) to throw out
static StringDEFAULT_PROGRAM_NAME
protected intindex
track index of tokens
protected MaplastRewriteTokenIndexes
Map String (program name) -> Integer index
static intMIN_TOKEN_INDEX
protected Mapprograms
You may have multiple, named streams of rewrite operations.
static intPROGRAM_INIT_SIZE
protected TokenStreamstream
Who do we suck tokens from?
protected Listtokens
Track the incoming list of tokens
Constructor Summary
TokenStreamRewriteEngine(TokenStream upstream)
TokenStreamRewriteEngine(TokenStream upstream, int initialSize)
Method Summary
protected voidaddToSortedRewriteList(TokenStreamRewriteEngine.RewriteOperation op)
If op.index > lastRewriteTokenIndexes, just add to the end.
protected voidaddToSortedRewriteList(String programName, TokenStreamRewriteEngine.RewriteOperation op)
Add an instruction to the rewrite instruction list ordered by the instruction number (use a binary search for efficiency).
voiddelete(int index)
voiddelete(int from, int to)
voiddelete(Token indexT)
voiddelete(Token from, Token to)
voiddelete(String programName, int from, int to)
voiddelete(String programName, Token from, Token to)
voiddeleteProgram()
voiddeleteProgram(String programName)
Reset the program so that no instructions exist
voiddiscard(int ttype)
StringgetEntireText()
intgetLastRewriteTokenIndex()
protected intgetLastRewriteTokenIndex(String programName)
TokenOffsetInfogetOffsetInfo(Token token)
protected ListgetProgram(String name)
TokenWithIndexgetToken(int i)
intgetTokenStreamSize()
intindex()
voidinsertAfter(Token t, String text)
voidinsertAfter(int index, String text)
voidinsertAfter(String programName, Token t, String text)
voidinsertAfter(String programName, int index, String text)
voidinsertBefore(Token t, String text)
voidinsertBefore(int index, String text)
voidinsertBefore(String programName, Token t, String text)
voidinsertBefore(String programName, int index, String text)
TokennextToken()
voidreplace(int index, String text)
voidreplace(int from, int to, String text)
voidreplace(Token indexT, String text)
voidreplace(Token from, Token to, String text)
voidreplace(String programName, int from, int to, String text)
voidreplace(String programName, Token from, Token to, String text)
voidrollback(int instructionIndex)
voidrollback(String programName, int instructionIndex)
Rollback the instruction stream for a program so that the indicated instruction (via instructionIndex) is no longer in the stream.
protected voidsetLastRewriteTokenIndex(String programName, int i)
intsize()
StringtoDebugString()
StringtoDebugString(int start, int end)
StringtoOriginalString()
StringtoOriginalString(int start, int end)
StringtoString()
StringtoString(String programName)
StringtoString(int start, int end)
StringtoString(String programName, int start, int end)

Field Detail

discardMask

protected BitSet discardMask
Which (whitespace) token(s) to throw out

DEFAULT_PROGRAM_NAME

public static final String DEFAULT_PROGRAM_NAME

index

protected int index
track index of tokens

lastRewriteTokenIndexes

protected Map lastRewriteTokenIndexes
Map String (program name) -> Integer index

MIN_TOKEN_INDEX

public static final int MIN_TOKEN_INDEX

programs

protected Map programs
You may have multiple, named streams of rewrite operations. I'm calling these things "programs." Maps String (name) -> rewrite (List)

PROGRAM_INIT_SIZE

public static final int PROGRAM_INIT_SIZE

stream

protected TokenStream stream
Who do we suck tokens from?

tokens

protected List tokens
Track the incoming list of tokens

Constructor Detail

TokenStreamRewriteEngine

public TokenStreamRewriteEngine(TokenStream upstream)

TokenStreamRewriteEngine

public TokenStreamRewriteEngine(TokenStream upstream, int initialSize)

Method Detail

addToSortedRewriteList

protected void addToSortedRewriteList(TokenStreamRewriteEngine.RewriteOperation op)
If op.index > lastRewriteTokenIndexes, just add to the end. Otherwise, do linear

addToSortedRewriteList

protected void addToSortedRewriteList(String programName, TokenStreamRewriteEngine.RewriteOperation op)
Add an instruction to the rewrite instruction list ordered by the instruction number (use a binary search for efficiency). The list is ordered so that toString() can be done efficiently. When there are multiple instructions at the same index, the instructions must be ordered to ensure proper behavior. For example, a delete at index i must kill any replace operation at i. Insert-before operations must come before any replace / delete instructions. If there are multiple insert instructions for a single index, they are done in reverse insertion order so that "insert foo" then "insert bar" yields "foobar" in front rather than "barfoo". This is convenient because I can insert new InsertOp instructions at the index returned by the binary search. A ReplaceOp kills any previous replace op. Since delete is the same as replace with null text, i can check for ReplaceOp and cover DeleteOp at same time. :)

delete

public void delete(int index)

delete

public void delete(int from, int to)

delete

public void delete(Token indexT)

delete

public void delete(Token from, Token to)

delete

public void delete(String programName, int from, int to)

delete

public void delete(String programName, Token from, Token to)

deleteProgram

public void deleteProgram()

deleteProgram

public void deleteProgram(String programName)
Reset the program so that no instructions exist

discard

public void discard(int ttype)

getEntireText

public String getEntireText()

getLastRewriteTokenIndex

public int getLastRewriteTokenIndex()

getLastRewriteTokenIndex

protected int getLastRewriteTokenIndex(String programName)

getOffsetInfo

public TokenOffsetInfo getOffsetInfo(Token token)

getProgram

protected List getProgram(String name)

getToken

public TokenWithIndex getToken(int i)

getTokenStreamSize

public int getTokenStreamSize()

index

public int index()

insertAfter

public void insertAfter(Token t, String text)

insertAfter

public void insertAfter(int index, String text)

insertAfter

public void insertAfter(String programName, Token t, String text)

insertAfter

public void insertAfter(String programName, int index, String text)

insertBefore

public void insertBefore(Token t, String text)

insertBefore

public void insertBefore(int index, String text)

insertBefore

public void insertBefore(String programName, Token t, String text)

insertBefore

public void insertBefore(String programName, int index, String text)

nextToken

public Token nextToken()

replace

public void replace(int index, String text)

replace

public void replace(int from, int to, String text)

replace

public void replace(Token indexT, String text)

replace

public void replace(Token from, Token to, String text)

replace

public void replace(String programName, int from, int to, String text)

replace

public void replace(String programName, Token from, Token to, String text)

rollback

public void rollback(int instructionIndex)

rollback

public void rollback(String programName, int instructionIndex)
Rollback the instruction stream for a program so that the indicated instruction (via instructionIndex) is no longer in the stream. UNTESTED!

setLastRewriteTokenIndex

protected void setLastRewriteTokenIndex(String programName, int i)

size

public int size()

toDebugString

public String toDebugString()

toDebugString

public String toDebugString(int start, int end)

toOriginalString

public String toOriginalString()

toOriginalString

public String toOriginalString(int start, int end)

toString

public String toString()

toString

public String toString(String programName)

toString

public String toString(int start, int end)

toString

public String toString(String programName, int start, int end)