| /* |
| * [The "BSD licence"] |
| * Copyright (c) 2005-2008 Terence Parr |
| * All rights reserved. |
| * |
| * Conversion to C#: |
| * Copyright (c) 2008-2009 Sam Harwell, Pixel Mine, Inc. |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * 3. The name of the author may not be used to endorse or promote products |
| * derived from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| namespace Antlr.Runtime.Tree |
| { |
| using StringBuilder = System.Text.StringBuilder; |
| |
| public class TreePatternLexer |
| { |
| public const int Begin = 1; |
| public const int End = 2; |
| public const int Id = 3; |
| public const int Arg = 4; |
| public const int Percent = 5; |
| public const int Colon = 6; |
| public const int Dot = 7; |
| |
| /** <summary>The tree pattern to lex like "(A B C)"</summary> */ |
| protected string pattern; |
| |
| /** <summary>Index into input string</summary> */ |
| protected int p = -1; |
| |
| /** <summary>Current char</summary> */ |
| protected int c; |
| |
| /** <summary>How long is the pattern in char?</summary> */ |
| protected int n; |
| |
| /** <summary>Set when token type is ID or ARG (name mimics Java's StreamTokenizer)</summary> */ |
| public StringBuilder sval = new StringBuilder(); |
| |
| public bool error = false; |
| |
| public TreePatternLexer( string pattern ) |
| { |
| this.pattern = pattern; |
| this.n = pattern.Length; |
| Consume(); |
| } |
| |
| public virtual int NextToken() |
| { |
| sval.Length = 0; // reset, but reuse buffer |
| while ( c != CharStreamConstants.EndOfFile ) |
| { |
| if ( c == ' ' || c == '\n' || c == '\r' || c == '\t' ) |
| { |
| Consume(); |
| continue; |
| } |
| if ( ( c >= 'a' && c <= 'z' ) || ( c >= 'A' && c <= 'Z' ) || c == '_' ) |
| { |
| sval.Append( (char)c ); |
| Consume(); |
| while ( ( c >= 'a' && c <= 'z' ) || ( c >= 'A' && c <= 'Z' ) || |
| ( c >= '0' && c <= '9' ) || c == '_' ) |
| { |
| sval.Append( (char)c ); |
| Consume(); |
| } |
| return Id; |
| } |
| if ( c == '(' ) |
| { |
| Consume(); |
| return Begin; |
| } |
| if ( c == ')' ) |
| { |
| Consume(); |
| return End; |
| } |
| if ( c == '%' ) |
| { |
| Consume(); |
| return Percent; |
| } |
| if ( c == ':' ) |
| { |
| Consume(); |
| return Colon; |
| } |
| if ( c == '.' ) |
| { |
| Consume(); |
| return Dot; |
| } |
| if ( c == '[' ) |
| { |
| // grab [x] as a string, returning x |
| Consume(); |
| while ( c != ']' ) |
| { |
| if ( c == '\\' ) |
| { |
| Consume(); |
| if ( c != ']' ) |
| { |
| sval.Append( '\\' ); |
| } |
| sval.Append( (char)c ); |
| } |
| else |
| { |
| sval.Append( (char)c ); |
| } |
| Consume(); |
| } |
| Consume(); |
| return Arg; |
| } |
| Consume(); |
| error = true; |
| return CharStreamConstants.EndOfFile; |
| } |
| return CharStreamConstants.EndOfFile; |
| } |
| |
| protected virtual void Consume() |
| { |
| p++; |
| if ( p >= n ) |
| { |
| c = CharStreamConstants.EndOfFile; |
| } |
| else |
| { |
| c = pattern[p]; |
| } |
| } |
| } |
| } |