1 // [The "BSD licence"] 2 // Copyright (c) 2006-2007 Kay Roepke 2010 Alan Condit 3 // All rights reserved. 4 // 5 // Redistribution and use in source and binary forms, with or without 6 // modification, are permitted provided that the following conditions 7 // are met: 8 // 1. Redistributions of source code must retain the above copyright 9 // notice, this list of conditions and the following disclaimer. 10 // 2. Redistributions in binary form must reproduce the above copyright 11 // notice, this list of conditions and the following disclaimer in the 12 // documentation and/or other materials provided with the distribution. 13 // 3. The name of the author may not be used to endorse or promote products 14 // derived from this software without specific prior written permission. 15 // 16 // THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 // IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 // OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 // IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 // INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 // NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 // THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 27 @protocol ANTLRIntStream < NSObject, NSCopying > 28 29 - (void) consume; 30 31 // Get unichar at current input pointer + i ahead where i=1 is next character as int for including ANTLRCharStreamEOF (-1) in the data range 32 - (NSInteger) LA:(NSInteger) i; 33 34 // Tell the stream to start buffering if it hasn't already. Return 35 // current input position, index(), or some other marker so that 36 // when passed to rewind() you get back to the same spot. 37 // rewind(mark()) should not affect the input cursor. 38 // TODO: problem in that lexer stream returns not index but some marker 39 40 - (NSInteger) mark; 41 42 // Return the current input symbol index 0..n where n indicates the 43 // last symbol has been read. 44 45 - (NSInteger) getIndex; 46 47 // Reset the stream so that next call to index would return marker. 48 // The marker will usually be -index but it doesn't have to be. It's 49 // just a marker to indicate what state the stream was in. This is 50 // essentially calling -release: and -seek:. If there are markers 51 // created after this marker argument, this routine must unroll them 52 // like a stack. Assume the state the stream was in when this marker 53 // was created. 54 55 - (void) rewind; 56 - (void) rewind:(NSInteger) marker; 57 58 // You may want to commit to a backtrack but don't want to force the 59 // stream to keep bookkeeping objects around for a marker that is 60 // no longer necessary. This will have the same behavior as 61 // rewind() except it releases resources without the backward seek. 62 63 - (void) release:(NSInteger) marker; 64 65 // Set the input cursor to the position indicated by index. This is 66 // normally used to seek ahead in the input stream. No buffering is 67 // required to do this unless you know your stream will use seek to 68 // move backwards such as when backtracking. 69 // This is different from rewind in its multi-directional 70 // requirement and in that its argument is strictly an input cursor (index). 71 // 72 // For char streams, seeking forward must update the stream state such 73 // as line number. For seeking backwards, you will be presumably 74 // backtracking using the mark/rewind mechanism that restores state and 75 // so this method does not need to update state when seeking backwards. 76 // 77 // Currently, this method is only used for efficient backtracking, but 78 // in the future it may be used for incremental parsing. 79 80 - (void) seek:(NSInteger) index; 81 82 /** Only makes sense for streams that buffer everything up probably, but 83 * might be useful to display the entire stream or for testing. This 84 * value includes a single EOF. 85 */ 86 - (NSUInteger) size; 87 /** Where are you getting symbols from? Normally, implementations will 88 * pass the buck all the way to the lexer who can ask its input stream 89 * for the file name or whatever. 90 */ 91 - (NSString *)getSourceName; 92 93 @end 94
