| java.lang.Object
 persistence.antlr.TokenStreamRewriteEngine
| TokenStreamRewriteEngine | | public class TokenStreamRewriteEngine implements TokenStream(Code) | | 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
|
| Inner Class :static class RewriteOperation | |
| Inner Class :static class InsertBeforeOp extends RewriteOperation | |
| Inner Class :static class ReplaceOp extends RewriteOperation | |
| Inner Class :static class DeleteOp extends ReplaceOp | |
| Method Summary | |
| protected void | addToSortedRewriteList(RewriteOperation op)
If op.index > lastRewriteTokenIndexes, just add to the end. | | protected void | addToSortedRewriteList(String programName, RewriteOperation op)
| | 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(String programName, int from, int to)
| | public void | delete(String programName, Token from, Token to)
| | public void | deleteProgram()
| | public void | deleteProgram(String programName)
| | public void | discard(int ttype)
| | public int | getLastRewriteTokenIndex()
| | protected int | getLastRewriteTokenIndex(String programName)
| | protected List | getProgram(String name)
| | public TokenWithIndex | getToken(int i)
| | public int | getTokenStreamSize()
| | public void | insertAfter(Token t, String text)
| | public void | insertAfter(int index, String text)
| | public void | insertAfter(String programName, Token t, String text)
| | public void | insertAfter(String programName, int index, String text)
| | public void | insertBefore(Token t, String text)
| | public void | insertBefore(int index, String text)
| | public void | insertBefore(String programName, Token t, String text)
| | public void | insertBefore(String programName, int index, String text)
| | public Token | nextToken()
| | public void | replace(int index, String text)
| | public void | replace(int from, int to, String text)
| | public void | replace(Token indexT, String text)
| | public void | replace(Token from, Token to, String text)
| | public void | replace(String programName, int from, int to, String text)
| | public void | replace(String programName, Token from, Token to, String text)
| | public void | rollback(int instructionIndex)
| | 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. | | protected void | setLastRewriteTokenIndex(String programName, int i)
| | public String | toDebugString()
| | public String | toDebugString(int start, int end)
| | public String | toOriginalString()
| | public String | toOriginalString(int start, int end)
| | public String | toString()
| | public String | toString(String programName)
| | public String | toString(int start, int end)
| | public String | toString(String programName, int start, int end)
|
| DEFAULT_PROGRAM_NAME | | final public static String DEFAULT_PROGRAM_NAME(Code) | | |
| MIN_TOKEN_INDEX | | final public static int MIN_TOKEN_INDEX(Code) | | |
| PROGRAM_INIT_SIZE | | final public static int PROGRAM_INIT_SIZE(Code) | | |
| discardMask | | protected BitSet discardMask(Code) | | Which (whitespace) token(s) to throw out
|
| index | | protected int index(Code) | | track index of tokens
|
| lastRewriteTokenIndexes | | protected Map lastRewriteTokenIndexes(Code) | | Map String (program name) -> Integer index
|
| programs | | protected Map programs(Code) | | You may have multiple, named streams of rewrite operations.
I'm calling these things "programs."
Maps String (name) -> rewrite (List)
|
| tokens | | protected List tokens(Code) | | Track the incoming list of tokens
|
| TokenStreamRewriteEngine | | public TokenStreamRewriteEngine(TokenStream upstream, int initialSize)(Code) | | |
| addToSortedRewriteList | | protected void addToSortedRewriteList(RewriteOperation op)(Code) | | If op.index > lastRewriteTokenIndexes, just add to the end.
Otherwise, do linear
|
| addToSortedRewriteList | | protected void addToSortedRewriteList(String programName, RewriteOperation op)(Code) | | |
| delete | | public void delete(int index)(Code) | | |
| delete | | public void delete(int from, int to)(Code) | | |
| delete | | public void delete(String programName, int from, int to)(Code) | | |
| deleteProgram | | public void deleteProgram()(Code) | | |
| deleteProgram | | public void deleteProgram(String programName)(Code) | | Reset the program so that no instructions exist
|
| discard | | public void discard(int ttype)(Code) | | |
| getLastRewriteTokenIndex | | public int getLastRewriteTokenIndex()(Code) | | |
| getLastRewriteTokenIndex | | protected int getLastRewriteTokenIndex(String programName)(Code) | | |
| getTokenStreamSize | | public int getTokenStreamSize()(Code) | | |
| insertAfter | | public void insertAfter(int index, String text)(Code) | | |
| insertBefore | | public void insertBefore(int index, String text)(Code) | | |
| replace | | public void replace(int from, int to, String text)(Code) | | |
| rollback | | public void rollback(int instructionIndex)(Code) | | |
| rollback | | public void rollback(String programName, int instructionIndex)(Code) | | 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)(Code) | | |
| toDebugString | | public String toDebugString(int start, int end)(Code) | | |
| toOriginalString | | public String toOriginalString(int start, int end)(Code) | | |
|
|