ANTLRIntStream.h revision 324c4644fee44b9898524c09511bd33c3f12e2df
1324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// [The "BSD licence"] 2324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// Copyright (c) 2006-2007 Kay Roepke 2010 Alan Condit 3324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// All rights reserved. 4324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// 5324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// Redistribution and use in source and binary forms, with or without 6324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// modification, are permitted provided that the following conditions 7324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// are met: 8324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// 1. Redistributions of source code must retain the above copyright 9324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// notice, this list of conditions and the following disclaimer. 10324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// 2. Redistributions in binary form must reproduce the above copyright 11324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// notice, this list of conditions and the following disclaimer in the 12324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// documentation and/or other materials provided with the distribution. 13324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// 3. The name of the author may not be used to endorse or promote products 14324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// derived from this software without specific prior written permission. 15324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// 16324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 27324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver@protocol ANTLRIntStream < NSObject, NSCopying > 28324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 29324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver- (void) consume; 30324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 31324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// Get unichar at current input pointer + i ahead where i=1 is next character as int for including ANTLRCharStreamEOF (-1) in the data range 32324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver- (NSInteger) LA:(NSInteger) i; 33324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 34324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// Tell the stream to start buffering if it hasn't already. Return 35324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// current input position, index(), or some other marker so that 36324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// when passed to rewind() you get back to the same spot. 37324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// rewind(mark()) should not affect the input cursor. 38324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// TODO: problem in that lexer stream returns not index but some marker 39324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 40324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver- (NSInteger) mark; 41324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 42324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// Return the current input symbol index 0..n where n indicates the 43324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// last symbol has been read. 44324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 45324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver- (NSInteger) getIndex; 46324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 47324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// Reset the stream so that next call to index would return marker. 48324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// The marker will usually be -index but it doesn't have to be. It's 49324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// just a marker to indicate what state the stream was in. This is 50324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// essentially calling -release: and -seek:. If there are markers 51324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// created after this marker argument, this routine must unroll them 52324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// like a stack. Assume the state the stream was in when this marker 53324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// was created. 54324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 55324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver- (void) rewind; 56324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver- (void) rewind:(NSInteger) marker; 57324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 58324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// You may want to commit to a backtrack but don't want to force the 59324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// stream to keep bookkeeping objects around for a marker that is 60324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// no longer necessary. This will have the same behavior as 61324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// rewind() except it releases resources without the backward seek. 62324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 63324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver- (void) release:(NSInteger) marker; 64324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 65324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// Set the input cursor to the position indicated by index. This is 66324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// normally used to seek ahead in the input stream. No buffering is 67324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// required to do this unless you know your stream will use seek to 68324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// move backwards such as when backtracking. 69324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// This is different from rewind in its multi-directional 70324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// requirement and in that its argument is strictly an input cursor (index). 71324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// 72324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// For char streams, seeking forward must update the stream state such 73324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// as line number. For seeking backwards, you will be presumably 74324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// backtracking using the mark/rewind mechanism that restores state and 75324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// so this method does not need to update state when seeking backwards. 76324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// 77324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// Currently, this method is only used for efficient backtracking, but 78324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// in the future it may be used for incremental parsing. 79324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 80324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver- (void) seek:(NSInteger) index; 81324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 82324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver/** Only makes sense for streams that buffer everything up probably, but 83324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * might be useful to display the entire stream or for testing. This 84324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * value includes a single EOF. 85324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver */ 86324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver- (NSUInteger) size; 87324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver/** Where are you getting symbols from? Normally, implementations will 88324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * pass the buck all the way to the lexer who can ask its input stream 89324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver * for the file name or whatever. 90324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver */ 91324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver- (NSString *)getSourceName; 92324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 93324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver@end 94