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52
53 package freemarker.core;
54
55 import freemarker.template.*;
56
57 final class UnaryPlusMinusExpression extends Expression {
58
59 private final Expression target;
60 private final boolean isMinus;
61 private static final Integer  MINUS_ONE = new Integer (-1);
62
63 UnaryPlusMinusExpression(Expression target, boolean isMinus) {
64 this.target = target;
65 this.isMinus = isMinus;
66 }
67
68 TemplateModel _getAsTemplateModel(Environment env) throws TemplateException {
69 TemplateNumberModel targetModel = null;
70 try {
71 targetModel = (TemplateNumberModel) target.getAsTemplateModel(env);
72 } catch (ClassCastException cce) {
73 String msg = "Error " + getStartLocation();
74 msg += "\nExpression " + target + " is not numerical.";
75 throw new NonNumericalException(msg, env);
76 }
77 if (!isMinus) {
78 return targetModel;
79 }
80 Number n = targetModel.getAsNumber();
81 n = ArithmeticEngine.CONSERVATIVE_ENGINE.multiply(MINUS_ONE, n);
82 return new SimpleNumber(n);
83 }
84
85 public String getCanonicalForm() {
86 String op = isMinus ? "-" : "+";
87 return op + target.getCanonicalForm();
88 }
89
90 boolean isLiteral() {
91 return target.isLiteral();
92 }
93
94 Expression _deepClone(String name, Expression subst) {
95 return new UnaryPlusMinusExpression(target.deepClone(name, subst), isMinus);
96 }
97 }
98 |
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