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1   ////////////////////////////////////////////////////////////////////////////////
2   // MillScript: an Open Spice interpreter and batch website creation tool
3   // Copyright (C) 2001-2004 Open World Ltd
4   //
5   // This file is part of MillScript.
6   //
7   // MillScript is free software; you can redistribute it and/or modify it under
8   // the terms of the GNU General Public License as published by the Free
9   // Software Foundation; either version 2 of the License, or (at your option)
10  // any later version.
11  //
12  // MillScript is distributed in the hope that it will be useful, but WITHOUT
13  // ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14  // FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
15  // more details.
16  //
17  // You should have received a copy of the GNU General Public License along with
18  // MillScript; if not, write to the Free Software Foundation, Inc., 59 Temple
19  // Place, Suite 330, Boston, MA  02111-1307  USA
20  ////////////////////////////////////////////////////////////////////////////////
21  package org.millscript.millscript.syntax;
22  
23  import org.millscript.millscript.expr.ApplyExpr;
24  import org.millscript.millscript.expr.CommaExpr;
25  import org.millscript.millscript.expr.Expr;
26  import org.millscript.millscript.expr.NameExpr;
27  
28  /**
29   * This class represents infix syntax, a variant of postfix syntax. This is used
30   * in situations where the syntax sits 'in'-between its arguments and maps to a
31   * function call. The syntax follows the form:
32   *
33   * <p>
34   * <code>&lt;expr&gt; S &lt;expr&gt;</code>
35   * </p>
36   *
37   * <p>
38   * which is very similar to the {@link SimplePostfixSyntax}, but it maps to a
39   * function call(actually an {@link ApplyExpr}). e.g. it's almost the equivalent
40   * of writing:
41   * </p>
42   *
43   * <p>
44   * <code>S( &lt;expr&gt;, &lt;expr&gt; )</code>
45   * </p>
46   *
47   * <p>
48   * To implement a new piece of infix syntax simply requires that you create a
49   * new function and map it to the relevant symbol in the {@link Parser}.
50   * </p>
51   *
52   * @see ApplyExpr
53   */
54  public class InfixSyntax extends PostfixSyntax {
55  
56      /**
57       * @see org.millscript.millscript.syntax.PostfixSyntaxInterface#postfix(java.lang.String, int, org.millscript.millscript.expr.Expr, org.millscript.millscript.syntax.Parser)
58       */
59      @Override
60      public ApplyExpr postfix( final String sym, final int prec, final Expr lhs, final Parser parser ) {
61          Expr rhs = parser.readExprPrec( prec );
62          return (
63              new ApplyExpr(
64                  new NameExpr( sym ),
65                  CommaExpr.make( lhs, rhs )
66              )
67          );
68      }
69  
70  }