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1 package kawa.standard;
2 import kawa.lang.*;
3 import gnu.bytecode.*;
4 import gnu.lists.*;
5 import gnu.expr.*;
6
7 public class syntax extends kawa.lang.Quote
8 {
9 public static final syntax syntax = new syntax("syntax", false);
10 public static final syntax quasiSyntax = new syntax("quasisyntax", true);
11
12 public syntax (String  name, boolean isQuasi)
13 {
14 super(name, isQuasi);
15 }
16
17 protected boolean expandColonForms ()
18 {
19 return false;
20 }
21
22 static final ClassType typeTemplateScope =
23 ClassType.make("kawa.lang.TemplateScope");
24 static final Method makeTemplateScopeMethod =
25 typeTemplateScope.getDeclaredMethod("make", 0);
26
27 public Expression rewriteForm (Pair form, Translator tr)
28 {
29 if (! (form.cdr instanceof Pair)
30 || (form = (Pair) (form.cdr)).cdr != LList.Empty)
31 return tr.syntaxError("syntax forms requires a single form");
32 Declaration saveTemplateScopeDecl = tr.templateScopeDecl;
33 if (saveTemplateScopeDecl == null)
34 {
35 tr.letStart();
36 Expression init =
37 new ApplyExp(makeTemplateScopeMethod,
38 Expression.noExpressions);
39 Declaration templateScopeDecl = tr.letVariable(null, typeTemplateScope, init);
40 templateScopeDecl.setCanRead();
41 tr.templateScopeDecl = templateScopeDecl;
42 tr.letEnter();
43 }
44
45 try
46 {
47 Expression body = coerceExpression(expand(form.car,
48 isQuasi ? 1 : Quote.QUOTE_DEPTH, tr),
49 tr);
50 return saveTemplateScopeDecl == null ? tr.letDone(body) : body;
51 }
52 finally
53 {
54 tr.templateScopeDecl = saveTemplateScopeDecl;
55 }
56 }
57
58 protected Expression leaf (Object val, Translator tr)
59 {
60 return makeSyntax(val, tr);
61 }
62
63 static Expression makeSyntax (Object form, Translator tr)
64 {
65 SyntaxTemplate template = new SyntaxTemplate(form, null, tr);
66 Expression matchArray = QuoteExp.nullExp;
67 PatternScope patternScope = tr.patternScope;
68 if (patternScope != null && patternScope.matchArray != null)
69 matchArray = new ReferenceExp(patternScope.matchArray);
70 Expression[] args = { new QuoteExp(template), matchArray, new ReferenceExp(tr.templateScopeDecl) };
71 return new ApplyExp(ClassType.make("kawa.lang.SyntaxTemplate")
72 .getDeclaredMethod("execute", 2),
73 args);
74 }
75 }
76 |
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