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
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(String programName,
Token from,
Token to)
delete
public void delete(String programName,
int from,
int to)
delete
public void delete(Token indexT)
delete
public void delete(int index)
delete
public void delete(int from,
int 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()
Returns the entire text input to the lexer.
- getEntireText in interface IASDebugStream
- The entire text or
null
, if error occured or System.in was used.
getLastRewriteTokenIndex
public int getLastRewriteTokenIndex()
getLastRewriteTokenIndex
protected int getLastRewriteTokenIndex(String programName)
getProgram
protected List getProgram(String name)
getTokenStreamSize
public int getTokenStreamSize()
insertAfter
public void insertAfter(String programName,
Token t,
String text)
insertAfter
public void insertAfter(String programName,
int index,
String text)
insertAfter
public void insertAfter(Token t,
String text)
insertAfter
public void insertAfter(int index,
String text)
insertBefore
public void insertBefore(String programName,
Token t,
String text)
insertBefore
public void insertBefore(String programName,
int index,
String text)
insertBefore
public void insertBefore(Token t,
String text)
insertBefore
public void insertBefore(int index,
String text)
replace
public void replace(String programName,
Token from,
Token to,
String text)
replace
public void replace(String programName,
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(int index,
String text)
replace
public void replace(int from,
int to,
String text)
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!
rollback
public void rollback(int instructionIndex)
setLastRewriteTokenIndex
protected void setLastRewriteTokenIndex(String programName,
int i)
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(String programName,
int start,
int end)
toString
public String toString(int start,
int end)