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LPEX 3.6.5 |
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public interface UCode_CharStream
This interface describes a character stream that maintains line and column number positions of the characters. It also has the capability to backup the stream to some extent. All the methods except backup can be implemented in any fashion. Method backup() needs to be implemented correctly for the correct operation of the generated lexers. The rest of the methods are all used to get information like line number, column number, and the String that constitutes a token, and are not used by the generated lexers. Therefore, their implementation won't affect the operation of these lexers. LPEX's implementation of this interface is com.ibm.lpex.core.LpexCharStream.
Field Summary | |
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static boolean |
staticFlag
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Method Summary | |
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void |
backup(int amount)
Backs up the input stream by amount steps. |
char |
BeginToken()
Returns the next character that marks the beginning of the next token. |
void |
Done()
The generated lexer calls this function to indicate that it is done with the stream, so implementations can free any resources held by this class. |
int |
getBeginColumn()
Returns the column number of the first character for the current token (being matched after the last call to BeginToken). |
int |
getBeginLine()
Returns the line number of the first character for the current token (being matched after the last call to BeginToken). |
int |
getEndColumn()
Returns the column number of the last character for the current token (being matched after the last call to BeginToken). |
int |
getEndLine()
Returns the line number of the last character for the current token (being matched after the last call to BeginToken). |
String |
GetImage()
Returns a string made up of characters from the marked token beginning to the current buffer position. |
char[] |
GetSuffix(int len)
Returns an array of characters that make up the suffix of length 'len' for the currently matched token. |
char |
readChar()
Returns the next character from the selected input. |
Field Detail |
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static final boolean staticFlag
Method Detail |
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char readChar() throws IOException
IOException
int getEndColumn()
int getEndLine()
int getBeginColumn()
int getBeginLine()
void backup(int amount)
char BeginToken() throws IOException
IOException
String GetImage()
char[] GetSuffix(int len)
{ String t = GetImage(); return t.substring(t.length() - len, t.length()).toCharArray(); }
void Done()
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LPEX 3.6.5 |
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