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
27 /**
28 * This class implements dot syntax. The dot syntax is used for function
29 * applications, allowing you to put function arguments on the left hand side of
30 * the function expression.
31 *
32 * <p>
33 * <code><expr>.<expr></code>
34 * </p>
35 *
36 * <p>
37 * The left hand side expression will be used as the first of the function
38 * arguments. The right hand side expression is made up of a function
39 * expression, optionally followed by any more arguments for the function.
40 * </p>
41 *
42 * @see ApplyExpr
43 */
44 public final class DotSyntax extends PostfixSyntax {
45
46 /**
47 * @see org.millscript.millscript.syntax.PostfixSyntaxInterface#postfix(java.lang.String, int, org.millscript.millscript.expr.Expr, org.millscript.millscript.syntax.Parser)
48 */
49 @Override
50 public ApplyExpr postfix( final String sym, final int prec, final Expr lhs, final Parser parser ) {
51 // We've read the first argument to the function, it's the lhs
52 // So now read the function expression
53 // NOTE - We read at a slightly higher precedence so the parser stops
54 // at the next dot or other higher precedence syntax
55 Expr f = parser.readExprPrec( prec + 1 );
56 // Check if we got a function application expression
57 if ( f instanceof ApplyExpr ) {
58 // We read an apply expression( e.g. f( x, y ) ) so we must build a
59 // new apply expression inserting the additional first argument
60 return (
61 new ApplyExpr(
62 ((ApplyExpr) f).getFun(),
63 CommaExpr.make( lhs, ((ApplyExpr) f).getArgs() )
64 )
65 );
66 } else {
67 // We've read another expression, which should be the function name
68 // expression but it could be a little more complex.
69 return new ApplyExpr( f, lhs );
70 }
71 }
72
73 }