/*
* gnu/regexp/RESyntax.java
* Copyright (C) 1998-2001 Wes Biggs
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
package gnu.regexp;
import java.io.Serializable;
import java.util.BitSet;
/**
* An RESyntax specifies the way a regular expression will be compiled.
* This class provides a number of predefined useful constants for
* emulating popular regular expression syntaxes. Additionally the
* user may construct his or her own syntax, using any combination of the
* syntax bit constants. The syntax is an optional argument to any of the
* matching methods on class RE.
*
* @author <A HREF="mailto:wes@cacas.org">Wes Biggs</A>
*/
public final class RESyntax implements Serializable {
static final String DEFAULT_LINE_SEPARATOR = System.getProperty("line.separator");
private static final String SYNTAX_IS_FINAL = RE.getLocalizedMessage("syntax.final");
private BitSet bits;
// true for the constant defined syntaxes
private boolean isFinal = false;
private String lineSeparator = DEFAULT_LINE_SEPARATOR;
// Values for constants are bit indexes
/**
* Syntax bit. Backslash is an escape character in lists.
*/
public static final int RE_BACKSLASH_ESCAPE_IN_LISTS = 0;
/**
* Syntax bit. Use \? instead of ? and \+ instead of +.
*/
public static final int RE_BK_PLUS_QM = 1;
/**
* Syntax bit. POSIX character classes ([:...:]) in lists are allowed.
*/
public static final int RE_CHAR_CLASSES = 2;
/**
* Syntax bit. ^ and $ are special everywhere.
* <B>Not implemented.</B>
*/
public static final int RE_CONTEXT_INDEP_ANCHORS = 3;
/**
* Syntax bit. Repetition operators are only special in valid positions.
* <B>Not implemented.</B>
*/
public static final int RE_CONTEXT_INDEP_OPS = 4;
/**
* Syntax bit. Repetition and alternation operators are invalid
* at start and end of pattern and other places.
* <B>Not implemented</B>.
*/
public static final int RE_CONTEXT_INVALID_OPS = 5;
/**
* Syntax bit. Match-any-character operator (.) matches a newline.
*/
public static final int RE_DOT_NEWLINE = 6;
/**
* Syntax bit. Match-any-character operator (.) does not match a null.
*/
public static final int RE_DOT_NOT_NULL = 7;
/**
* Syntax bit. Intervals ({x}, {x,}, {x,y}) are allowed.
*/
public static final int RE_INTERVALS = 8;
/**
* Syntax bit. No alternation (|), match one-or-more (+), or
* match zero-or-one (?) operators.
*/
public static final int RE_LIMITED_OPS = 9;
/**
* Syntax bit. Newline is an alternation operator.
*/
public static final int RE_NEWLINE_ALT = 10; // impl.
/**
* Syntax bit. Intervals use { } instead of \{ \}
*/
public static final int RE_NO_BK_BRACES = 11;
/**
* Syntax bit. Grouping uses ( ) instead of \( \).
*/
public static final int RE_NO_BK_PARENS = 12;
/**
* Syntax bit. Backreferences not allowed.
*/
public static final int RE_NO_BK_REFS = 13;
/**
* Syntax bit. Alternation uses | instead of \|
*/
public static final int RE_NO_BK_VBAR = 14;
/**
* Syntax bit. <B>Not implemented</B>.
*/
public static final int RE_NO_EMPTY_RANGES = 15;
/**
* Syntax bit. An unmatched right parenthesis (')' or '\)', depending
* on RE_NO_BK_PARENS) will throw an exception when compiling.
*/
public static final int RE_UNMATCHED_RIGHT_PAREN_ORD = 16;
/**
* Syntax bit. <B>Not implemented.</B>
*/
public static final int RE_HAT_LISTS_NOT_NEWLINE = 17;
/**
* Syntax bit. Stingy matching is allowed (+?, *?, ??, {x,y}?).
*/
public static final int RE_STINGY_OPS = 18;
/**
* Syntax bit. Allow character class escapes (\d, \D, \s, \S, \w, \W).
*/
public static final int RE_CHAR_CLASS_ESCAPES = 19;
/**
* Syntax bit. Allow use of (?:xxx) grouping (subexpression is not saved).
*/
public static final int RE_PURE_GROUPING = 20;
/**
* Syntax bit. Allow use of (?=xxx) and (?!xxx) apply the subexpression
* to the text following the current position without consuming that text.
*/
public static final int RE_LOOKAHEAD = 21;
/**
* Syntax bit. Allow beginning- and end-of-string anchors (\A, \Z).
*/
public static final int RE_STRING_ANCHORS = 22;
/**
* Syntax bit. Allow embedded comments, (?#comment), as in Perl5.
*/
public static final int RE_COMMENTS = 23;
/**
* Syntax bit. Allow character class escapes within lists, as in Perl5.
*/
public static final int RE_CHAR_CLASS_ESC_IN_LISTS = 24;
private static final int BIT_TOTAL = 25;
/**
* Predefined syntax.
* Emulates regular expression support in the awk utility.
*/
public static final RESyntax RE_SYNTAX_AWK;
/**
* Predefined syntax.
* Emulates regular expression support in the ed utility.
*/
public static final RESyntax RE_SYNTAX_ED;
/**
* Predefined syntax.
* Emulates regular expression support in the egrep utility.
*/
public static final RESyntax RE_SYNTAX_EGREP;
/**
* Predefined syntax.
* Emulates regular expression support in the GNU Emacs editor.
*/
public static final RESyntax RE_SYNTAX_EMACS;
/**
* Predefined syntax.
* Emulates regular expression support in the grep utility.
*/
public static final RESyntax RE_SYNTAX_GREP;
/**
* Predefined syntax.
* Emulates regular expression support in the POSIX awk specification.
*/
public static final RESyntax RE_SYNTAX_POSIX_AWK;
/**
* Predefined syntax.
* Emulates POSIX basic regular expression support.
*/
public static final RESyntax RE_SYNTAX_POSIX_BASIC;
/**
* Predefined syntax.
* Emulates regular expression support in the POSIX egrep specification.
*/
public static final RESyntax RE_SYNTAX_POSIX_EGREP;
/**
* Predefined syntax.
* Emulates POSIX extended regular expression support.
*/
public static final RESyntax RE_SYNTAX_POSIX_EXTENDED;
/**
* Predefined syntax.
* Emulates POSIX basic minimal regular expressions.
*/
public static final RESyntax RE_SYNTAX_POSIX_MINIMAL_BASIC;
/**
* Predefined syntax.
* Emulates POSIX extended minimal regular expressions.
*/
public static final RESyntax RE_SYNTAX_POSIX_MINIMAL_EXTENDED;
/**
* Predefined syntax.
* Emulates regular expression support in the sed utility.
*/
public static final RESyntax RE_SYNTAX_SED;
/**
* Predefined syntax.
* Emulates regular expression support in Larry Wall's perl, version 4,
*/
public static final RESyntax RE_SYNTAX_PERL4;
/**
* Predefined syntax.
* Emulates regular expression support in Larry Wall's perl, version 4,
* using single line mode (/s modifier).
*/
public static final RESyntax RE_SYNTAX_PERL4_S; // single line mode (/s)
/**
* Predefined syntax.
* Emulates regular expression support in Larry Wall's perl, version 5.
*/
public static final RESyntax RE_SYNTAX_PERL5;
/**
* Predefined syntax.
* Emulates regular expression support in Larry Wall's perl, version 5,
* using single line mode (/s modifier).
*/
public static final RESyntax RE_SYNTAX_PERL5_S;
static {
// Define syntaxes
RE_SYNTAX_EMACS = new RESyntax().makeFinal();
RESyntax RE_SYNTAX_POSIX_COMMON = new RESyntax()
.set(RE_CHAR_CLASSES)
.set(RE_DOT_NEWLINE)
.set(RE_DOT_NOT_NULL)
.set(RE_INTERVALS)
.set(RE_NO_EMPTY_RANGES)
.makeFinal();
RE_SYNTAX_POSIX_BASIC = new RESyntax(RE_SYNTAX_POSIX_COMMON)
.set(RE_BK_PLUS_QM)
.makeFinal();
RE_SYNTAX_POSIX_EXTENDED = new RESyntax(RE_SYNTAX_POSIX_COMMON)
.set(RE_CONTEXT_INDEP_ANCHORS)
.set(RE_CONTEXT_INDEP_OPS)
.set(RE_NO_BK_BRACES)
.set(RE_NO_BK_PARENS)
.set(RE_NO_BK_VBAR)
.set(RE_UNMATCHED_RIGHT_PAREN_ORD)
.makeFinal();
RE_SYNTAX_AWK = new RESyntax()
.set(RE_BACKSLASH_ESCAPE_IN_LISTS)
.set(RE_DOT_NOT_NULL)
.set(RE_NO_BK_PARENS)
.set(RE_NO_BK_REFS)
.set(RE_NO_BK_VBAR)
.set(RE_NO_EMPTY_RANGES)
.set(RE_UNMATCHED_RIGHT_PAREN_ORD)
.makeFinal();
RE_SYNTAX_POSIX_AWK = new RESyntax(RE_SYNTAX_POSIX_EXTENDED)
.set(RE_BACKSLASH_ESCAPE_IN_LISTS)
.makeFinal();
RE_SYNTAX_GREP = new RESyntax()
.set(RE_BK_PLUS_QM)
.set(RE_CHAR_CLASSES)
.set(RE_HAT_LISTS_NOT_NEWLINE)
.set(RE_INTERVALS)
.set(RE_NEWLINE_ALT)
.makeFinal();
RE_SYNTAX_EGREP = new RESyntax()
.set(RE_CHAR_CLASSES)
.set(RE_CONTEXT_INDEP_ANCHORS)
.set(RE_CONTEXT_INDEP_OPS)
.set(RE_HAT_LISTS_NOT_NEWLINE)
.set(RE_NEWLINE_ALT)
.set(RE_NO_BK_PARENS)
.set(RE_NO_BK_VBAR)
.makeFinal();
RE_SYNTAX_POSIX_EGREP = new RESyntax(RE_SYNTAX_EGREP)
.set(RE_INTERVALS)
.set(RE_NO_BK_BRACES)
.makeFinal();
/* P1003.2/D11.2, section 4.20.7.1, lines 5078ff. */
RE_SYNTAX_ED = new RESyntax(RE_SYNTAX_POSIX_BASIC)
.makeFinal();
RE_SYNTAX_SED = new RESyntax(RE_SYNTAX_POSIX_BASIC)
.makeFinal();
RE_SYNTAX_POSIX_MINIMAL_BASIC = new RESyntax(RE_SYNTAX_POSIX_COMMON)
.set(RE_LIMITED_OPS)
.makeFinal();
/* Differs from RE_SYNTAX_POSIX_EXTENDED in that RE_CONTEXT_INVALID_OPS
replaces RE_CONTEXT_INDEP_OPS and RE_NO_BK_REFS is added. */
RE_SYNTAX_POSIX_MINIMAL_EXTENDED = new RESyntax(RE_SYNTAX_POSIX_COMMON)
.set(RE_CONTEXT_INDEP_ANCHORS)
.set(RE_CONTEXT_INVALID_OPS)
.set(RE_NO_BK_BRACES)
.set(RE_NO_BK_PARENS)
.set(RE_NO_BK_REFS)
.set(RE_NO_BK_VBAR)
.set(RE_UNMATCHED_RIGHT_PAREN_ORD)
.makeFinal();
/* There is no official Perl spec, but here's a "best guess" */
RE_SYNTAX_PERL4 = new RESyntax()
.set(RE_BACKSLASH_ESCAPE_IN_LISTS)
.set(RE_CONTEXT_INDEP_ANCHORS)
.set(RE_CONTEXT_INDEP_OPS) // except for '{', apparently
.set(RE_INTERVALS)
.set(RE_NO_BK_BRACES)
.set(RE_NO_BK_PARENS)
.set(RE_NO_BK_VBAR)
.set(RE_NO_EMPTY_RANGES)
.set(RE_CHAR_CLASS_ESCAPES) // \d,\D,\w,\W,\s,\S
.makeFinal();
RE_SYNTAX_PERL4_S = new RESyntax(RE_SYNTAX_PERL4)
.set(RE_DOT_NEWLINE)
.makeFinal();
RE_SYNTAX_PERL5 = new RESyntax(RE_SYNTAX_PERL4)
.set(RE_PURE_GROUPING) // (?:)
.set(RE_STINGY_OPS) // *?,??,+?,{}?
.set(RE_LOOKAHEAD) // (?=)(?!)
.set(RE_STRING_ANCHORS) // \A,\Z
.set(RE_CHAR_CLASS_ESC_IN_LISTS)// \d,\D,\w,\W,\s,\S within []
.set(RE_COMMENTS) // (?#)
.makeFinal();
RE_SYNTAX_PERL5_S = new RESyntax(RE_SYNTAX_PERL5)
.set(RE_DOT_NEWLINE)
.makeFinal();
}
/**
* Construct a new syntax object with all bits turned off.
* This is equivalent to RE_SYNTAX_EMACS.
*/
public RESyntax() {
bits = new BitSet(BIT_TOTAL);
}
/**
* Called internally when constructing predefined syntaxes
* so their interpretation cannot vary. Conceivably useful
* for your syntaxes as well. Causes IllegalAccessError to
* be thrown if any attempt to modify the syntax is made.
*
* @return this object for convenient chaining
*/
public RESyntax makeFinal() {
isFinal = true;
return this;
}
/**
* Construct a new syntax object with all bits set the same
* as the other syntax.
*/
public RESyntax(RESyntax other) {
bits = (BitSet) other.bits.clone();
}
/**
* Check if a given bit is set in this syntax.
*/
public boolean get(int index) {
return bits.get(index);
}
/**
* Set a given bit in this syntax.
*
* @param index the constant (RESyntax.RE_xxx) bit to set.
* @return a reference to this object for easy chaining.
*/
public RESyntax set(int index) {
if (isFinal) throw new IllegalAccessError(SYNTAX_IS_FINAL);
bits.set(index);
return this;
}
/**
* Clear a given bit in this syntax.
*
* @param index the constant (RESyntax.RE_xxx) bit to clear.
* @return a reference to this object for easy chaining.
*/
public RESyntax clear(int index) {
if (isFinal) throw new IllegalAccessError(SYNTAX_IS_FINAL);
bits.clear(index);
return this;
}
/**
* Changes the line separator string for regular expressions
* created using this RESyntax. The default separator is the
* value returned by the system property "line.separator", which
* should be correct when reading platform-specific files from a
* filesystem. However, many programs may collect input from
* sources where the line separator is differently specified (for
* example, in the applet environment, the text box widget
* interprets line breaks as single-character newlines,
* regardless of the host platform.
*
* Note that setting the line separator to a character or
* characters that have specific meaning within the current syntax
* can cause unexpected chronosynclastic infundibula.
*
* @return this object for convenient chaining
*/
public RESyntax setLineSeparator(String aSeparator) {
if (isFinal) throw new IllegalAccessError(SYNTAX_IS_FINAL);
lineSeparator = aSeparator;
return this;
}
/**
* Returns the currently active line separator string. The default
* is the platform-dependent system property "line.separator".
*/
public String getLineSeparator() {
return lineSeparator;
}
}