/* The following code was generated by JFlex 1.4.3 on 8/16/09 3:19 PM */ /* This example comes from a short article series in the Linux Gazette by Richard A. Sevenich and Christopher Lopes, titled "Compiler Construction Tools". The article series starts at http://www.linuxgazette.com/issue39/sevenich.html Small changes and updates to newest JFlex+Cup versions by Gerwin Klein */ /* Commented By: Christopher Lopes File Name: lcalc.flex To Create: > jflex lcalc.flex and then after the parser is created > javac Lexer.java */ /* --------------------------Usercode Section------------------------ */ import java_cup.runtime.*; /** * This class is a scanner generated by * JFlex 1.4.3 * on 8/16/09 3:19 PM from the specification file * lcalc.flex */ class Lexer implements java_cup.runtime.Scanner { /** This character denotes the end of file */ public static final int YYEOF = -1; /** initial size of the lookahead buffer */ private static final int ZZ_BUFFERSIZE = 16384; /** lexical states */ public static final int YYINITIAL = 0; /** * ZZ_LEXSTATE[l] is the state in the DFA for the lexical state l * ZZ_LEXSTATE[l+1] is the state in the DFA for the lexical state l * at the beginning of a line * l is of the form l = 2*k, k a non negative integer */ private static final int ZZ_LEXSTATE[] = { 0, 0 }; /** * Translates characters to character classes */ private static final String ZZ_CMAP_PACKED = "\11\0\1\3\1\2\1\0\1\3\1\1\22\0\1\3\7\0\1\14"+ "\1\15\1\12\1\10\1\0\1\11\1\0\1\13\1\4\11\5\1\0"+ "\1\7\5\0\32\6\4\0\1\6\1\0\32\6\uff85\0"; /** * Translates characters to character classes */ private static final char [] ZZ_CMAP = zzUnpackCMap(ZZ_CMAP_PACKED); /** * Translates DFA states to action switch labels. */ private static final int [] ZZ_ACTION = zzUnpackAction(); private static final String ZZ_ACTION_PACKED_0 = "\1\0\1\1\2\2\2\3\1\4\1\5\1\6\1\7"+ "\1\10\1\11\1\12\1\13"; private static int [] zzUnpackAction() { int [] result = new int[14]; int offset = 0; offset = zzUnpackAction(ZZ_ACTION_PACKED_0, offset, result); return result; } private static int zzUnpackAction(String packed, int offset, int [] result) { int i = 0; /* index in packed string */ int j = offset; /* index in unpacked array */ int l = packed.length(); while (i < l) { int count = packed.charAt(i++); int value = packed.charAt(i++); do result[j++] = value; while (--count > 0); } return j; } /** * Translates a state to a row index in the transition table */ private static final int [] ZZ_ROWMAP = zzUnpackRowMap(); private static final String ZZ_ROWMAP_PACKED_0 = "\0\0\0\16\0\34\0\16\0\16\0\52\0\70\0\16"+ "\0\16\0\16\0\16\0\16\0\16\0\16"; private static int [] zzUnpackRowMap() { int [] result = new int[14]; int offset = 0; offset = zzUnpackRowMap(ZZ_ROWMAP_PACKED_0, offset, result); return result; } private static int zzUnpackRowMap(String packed, int offset, int [] result) { int i = 0; /* index in packed string */ int j = offset; /* index in unpacked array */ int l = packed.length(); while (i < l) { int high = packed.charAt(i++) << 16; result[j++] = high | packed.charAt(i++); } return j; } /** * The transition table of the DFA */ private static final int [] ZZ_TRANS = zzUnpackTrans(); private static final String ZZ_TRANS_PACKED_0 = "\1\2\1\3\2\4\1\5\1\6\1\7\1\10\1\11"+ "\1\12\1\13\1\14\1\15\1\16\20\0\1\4\17\0"+ "\2\6\14\0\3\7\7\0"; private static int [] zzUnpackTrans() { int [] result = new int[70]; int offset = 0; offset = zzUnpackTrans(ZZ_TRANS_PACKED_0, offset, result); return result; } private static int zzUnpackTrans(String packed, int offset, int [] result) { int i = 0; /* index in packed string */ int j = offset; /* index in unpacked array */ int l = packed.length(); while (i < l) { int count = packed.charAt(i++); int value = packed.charAt(i++); value--; do result[j++] = value; while (--count > 0); } return j; } /* error codes */ private static final int ZZ_UNKNOWN_ERROR = 0; private static final int ZZ_NO_MATCH = 1; private static final int ZZ_PUSHBACK_2BIG = 2; /* error messages for the codes above */ private static final String ZZ_ERROR_MSG[] = { "Unkown internal scanner error", "Error: could not match input", "Error: pushback value was too large" }; /** * ZZ_ATTRIBUTE[aState] contains the attributes of state aState */ private static final int [] ZZ_ATTRIBUTE = zzUnpackAttribute(); private static final String ZZ_ATTRIBUTE_PACKED_0 = "\1\0\1\11\1\1\2\11\2\1\7\11"; private static int [] zzUnpackAttribute() { int [] result = new int[14]; int offset = 0; offset = zzUnpackAttribute(ZZ_ATTRIBUTE_PACKED_0, offset, result); return result; } private static int zzUnpackAttribute(String packed, int offset, int [] result) { int i = 0; /* index in packed string */ int j = offset; /* index in unpacked array */ int l = packed.length(); while (i < l) { int count = packed.charAt(i++); int value = packed.charAt(i++); do result[j++] = value; while (--count > 0); } return j; } /** the input device */ private java.io.Reader zzReader; /** the current state of the DFA */ private int zzState; /** the current lexical state */ private int zzLexicalState = YYINITIAL; /** this buffer contains the current text to be matched and is the source of the yytext() string */ private char zzBuffer[] = new char[ZZ_BUFFERSIZE]; /** the textposition at the last accepting state */ private int zzMarkedPos; /** the current text position in the buffer */ private int zzCurrentPos; /** startRead marks the beginning of the yytext() string in the buffer */ private int zzStartRead; /** endRead marks the last character in the buffer, that has been read from input */ private int zzEndRead; /** number of newlines encountered up to the start of the matched text */ private int yyline; /** the number of characters up to the start of the matched text */ private int yychar; /** * the number of characters from the last newline up to the start of the * matched text */ private int yycolumn; /** * zzAtBOL == true <=> the scanner is currently at the beginning of a line */ private boolean zzAtBOL = true; /** zzAtEOF == true <=> the scanner is at the EOF */ private boolean zzAtEOF; /** denotes if the user-EOF-code has already been executed */ private boolean zzEOFDone; /* user code: */ /* To create a new java_cup.runtime.Symbol with information about the current token, the token will have no value in this case. */ private Symbol symbol(int type) { return new Symbol(type, yyline, yycolumn); } /* Also creates a new java_cup.runtime.Symbol with information about the current token, but this object has a value. */ private Symbol symbol(int type, Object value) { return new Symbol(type, yyline, yycolumn, value); } /** * Creates a new scanner * There is also a java.io.InputStream version of this constructor. * * @param in the java.io.Reader to read input from. */ Lexer(java.io.Reader in) { this.zzReader = in; } /** * Creates a new scanner. * There is also java.io.Reader version of this constructor. * * @param in the java.io.Inputstream to read input from. */ Lexer(java.io.InputStream in) { this(new java.io.InputStreamReader(in)); } /** * Unpacks the compressed character translation table. * * @param packed the packed character translation table * @return the unpacked character translation table */ private static char [] zzUnpackCMap(String packed) { char [] map = new char[0x10000]; int i = 0; /* index in packed string */ int j = 0; /* index in unpacked array */ while (i < 56) { int count = packed.charAt(i++); char value = packed.charAt(i++); do map[j++] = value; while (--count > 0); } return map; } /** * Refills the input buffer. * * @return false, iff there was new input. * * @exception java.io.IOException if any I/O-Error occurs */ private boolean zzRefill() throws java.io.IOException { /* first: make room (if you can) */ if (zzStartRead > 0) { System.arraycopy(zzBuffer, zzStartRead, zzBuffer, 0, zzEndRead-zzStartRead); /* translate stored positions */ zzEndRead-= zzStartRead; zzCurrentPos-= zzStartRead; zzMarkedPos-= zzStartRead; zzStartRead = 0; } /* is the buffer big enough? */ if (zzCurrentPos >= zzBuffer.length) { /* if not: blow it up */ char newBuffer[] = new char[zzCurrentPos*2]; System.arraycopy(zzBuffer, 0, newBuffer, 0, zzBuffer.length); zzBuffer = newBuffer; } /* finally: fill the buffer with new input */ int numRead = zzReader.read(zzBuffer, zzEndRead, zzBuffer.length-zzEndRead); if (numRead > 0) { zzEndRead+= numRead; return false; } // unlikely but not impossible: read 0 characters, but not at end of stream if (numRead == 0) { int c = zzReader.read(); if (c == -1) { return true; } else { zzBuffer[zzEndRead++] = (char) c; return false; } } // numRead < 0 return true; } /** * Closes the input stream. */ public final void yyclose() throws java.io.IOException { zzAtEOF = true; /* indicate end of file */ zzEndRead = zzStartRead; /* invalidate buffer */ if (zzReader != null) zzReader.close(); } /** * Resets the scanner to read from a new input stream. * Does not close the old reader. * * All internal variables are reset, the old input stream * cannot be reused (internal buffer is discarded and lost). * Lexical state is set to ZZ_INITIAL. * * @param reader the new input stream */ public final void yyreset(java.io.Reader reader) { zzReader = reader; zzAtBOL = true; zzAtEOF = false; zzEOFDone = false; zzEndRead = zzStartRead = 0; zzCurrentPos = zzMarkedPos = 0; yyline = yychar = yycolumn = 0; zzLexicalState = YYINITIAL; } /** * Returns the current lexical state. */ public final int yystate() { return zzLexicalState; } /** * Enters a new lexical state * * @param newState the new lexical state */ public final void yybegin(int newState) { zzLexicalState = newState; } /** * Returns the text matched by the current regular expression. */ public final String yytext() { return new String( zzBuffer, zzStartRead, zzMarkedPos-zzStartRead ); } /** * Returns the character at position pos from the * matched text. * * It is equivalent to yytext().charAt(pos), but faster * * @param pos the position of the character to fetch. * A value from 0 to yylength()-1. * * @return the character at position pos */ public final char yycharat(int pos) { return zzBuffer[zzStartRead+pos]; } /** * Returns the length of the matched text region. */ public final int yylength() { return zzMarkedPos-zzStartRead; } /** * Reports an error that occured while scanning. * * In a wellformed scanner (no or only correct usage of * yypushback(int) and a match-all fallback rule) this method * will only be called with things that "Can't Possibly Happen". * If this method is called, something is seriously wrong * (e.g. a JFlex bug producing a faulty scanner etc.). * * Usual syntax/scanner level error handling should be done * in error fallback rules. * * @param errorCode the code of the errormessage to display */ private void zzScanError(int errorCode) { String message; try { message = ZZ_ERROR_MSG[errorCode]; } catch (ArrayIndexOutOfBoundsException e) { message = ZZ_ERROR_MSG[ZZ_UNKNOWN_ERROR]; } throw new Error(message); } /** * Pushes the specified amount of characters back into the input stream. * * They will be read again by then next call of the scanning method * * @param number the number of characters to be read again. * This number must not be greater than yylength()! */ public void yypushback(int number) { if ( number > yylength() ) zzScanError(ZZ_PUSHBACK_2BIG); zzMarkedPos -= number; } /** * Contains user EOF-code, which will be executed exactly once, * when the end of file is reached */ private void zzDoEOF() throws java.io.IOException { if (!zzEOFDone) { zzEOFDone = true; yyclose(); } } /** * Resumes scanning until the next regular expression is matched, * the end of input is encountered or an I/O-Error occurs. * * @return the next token * @exception java.io.IOException if any I/O-Error occurs */ public java_cup.runtime.Symbol next_token() throws java.io.IOException { int zzInput; int zzAction; // cached fields: int zzCurrentPosL; int zzMarkedPosL; int zzEndReadL = zzEndRead; char [] zzBufferL = zzBuffer; char [] zzCMapL = ZZ_CMAP; int [] zzTransL = ZZ_TRANS; int [] zzRowMapL = ZZ_ROWMAP; int [] zzAttrL = ZZ_ATTRIBUTE; while (true) { zzMarkedPosL = zzMarkedPos; boolean zzR = false; for (zzCurrentPosL = zzStartRead; zzCurrentPosL < zzMarkedPosL; zzCurrentPosL++) { switch (zzBufferL[zzCurrentPosL]) { case '\u000B': case '\u000C': case '\u0085': case '\u2028': case '\u2029': yyline++; yycolumn = 0; zzR = false; break; case '\r': yyline++; yycolumn = 0; zzR = true; break; case '\n': if (zzR) zzR = false; else { yyline++; yycolumn = 0; } break; default: zzR = false; yycolumn++; } } if (zzR) { // peek one character ahead if it is \n (if we have counted one line too much) boolean zzPeek; if (zzMarkedPosL < zzEndReadL) zzPeek = zzBufferL[zzMarkedPosL] == '\n'; else if (zzAtEOF) zzPeek = false; else { boolean eof = zzRefill(); zzEndReadL = zzEndRead; zzMarkedPosL = zzMarkedPos; zzBufferL = zzBuffer; if (eof) zzPeek = false; else zzPeek = zzBufferL[zzMarkedPosL] == '\n'; } if (zzPeek) yyline--; } zzAction = -1; zzCurrentPosL = zzCurrentPos = zzStartRead = zzMarkedPosL; zzState = ZZ_LEXSTATE[zzLexicalState]; zzForAction: { while (true) { if (zzCurrentPosL < zzEndReadL) zzInput = zzBufferL[zzCurrentPosL++]; else if (zzAtEOF) { zzInput = YYEOF; break zzForAction; } else { // store back cached positions zzCurrentPos = zzCurrentPosL; zzMarkedPos = zzMarkedPosL; boolean eof = zzRefill(); // get translated positions and possibly new buffer zzCurrentPosL = zzCurrentPos; zzMarkedPosL = zzMarkedPos; zzBufferL = zzBuffer; zzEndReadL = zzEndRead; if (eof) { zzInput = YYEOF; break zzForAction; } else { zzInput = zzBufferL[zzCurrentPosL++]; } } int zzNext = zzTransL[ zzRowMapL[zzState] + zzCMapL[zzInput] ]; if (zzNext == -1) break zzForAction; zzState = zzNext; int zzAttributes = zzAttrL[zzState]; if ( (zzAttributes & 1) == 1 ) { zzAction = zzState; zzMarkedPosL = zzCurrentPosL; if ( (zzAttributes & 8) == 8 ) break zzForAction; } } } // store back cached position zzMarkedPos = zzMarkedPosL; switch (zzAction < 0 ? zzAction : ZZ_ACTION[zzAction]) { case 6: { System.out.print(" + "); return symbol(sym.PLUS); } case 12: break; case 9: { System.out.print(" / "); return symbol(sym.DIVIDE); } case 13: break; case 5: { return symbol(sym.SEMI); } case 14: break; case 8: { System.out.print(" * "); return symbol(sym.TIMES); } case 15: break; case 3: { System.out.print(yytext()); return symbol(sym.NUMBER, new Integer(yytext())); } case 16: break; case 11: { System.out.print(" ) "); return symbol(sym.RPAREN); } case 17: break; case 4: { System.out.print(yytext()); return symbol(sym.ID, new Integer(1)); } case 18: break; case 2: { /* just skip what was found, do nothing */ } case 19: break; case 10: { System.out.print(" ( "); return symbol(sym.LPAREN); } case 20: break; case 7: { System.out.print(" - "); return symbol(sym.MINUS); } case 21: break; case 1: { throw new Error("Illegal character <"+yytext()+">"); } case 22: break; default: if (zzInput == YYEOF && zzStartRead == zzCurrentPos) { zzAtEOF = true; zzDoEOF(); { return new java_cup.runtime.Symbol(sym.EOF); } } else { zzScanError(ZZ_NO_MATCH); } } } } }