Added an expression parser.

src/test/java/com/sk89q/worldedit/expression/ExpressionTest.java

@@ -0,0 +1,66 @@
+package com.sk89q.worldedit.expression;
+
+import static org.junit.Assert.*;
+import static java.lang.Math.*;
+
+import org.junit.*;
+
+import com.sk89q.worldedit.expression.lexer.LexerException;
+import com.sk89q.worldedit.expression.parser.ParserException;
+
+public class ExpressionTest {
+    @Test
+    public void testEvaluate() throws Exception {
+        // check 
+        assertEquals(1-2+3, simpleEval("1-2+3"), 0);
+
+        // check unary ops
+        assertEquals(2+ +4, simpleEval("2++4"), 0);
+        assertEquals(2- -4, simpleEval("2--4"), 0);
+        assertEquals(2*-4, simpleEval("2*-4"), 0);
+
+        // check functions
+        assertEquals(sin(5), simpleEval("sin(5)"), 0);
+        assertEquals(atan2(3,4), simpleEval("atan2(3,4)"), 0);
+
+        // check variables
+        assertEquals(8, Expression.compile("foo+bar", "foo", "bar").evaluate(5, 3), 0);
+    }
+
+    @Test
+    public void testErrors() throws ExpressionException {
+        // test lexer errors
+        try {
+            Expression.compile("{");
+            fail("Error expected");
+        } catch (LexerException e) {
+            assertEquals("Error position", 0, e.getPosition());
+        }
+
+        // test parser errors
+        try {
+            Expression.compile("x");
+            fail("Error expected");
+        } catch (ParserException e) {
+            assertEquals("Error position", 0, e.getPosition());
+        }
+        try {
+            Expression.compile("x()");
+            fail("Error expected");
+        } catch (ParserException e) {
+            assertEquals("Error position", 0, e.getPosition());
+        }
+        try {
+            Expression.compile("(");
+            fail("Error expected");
+        } catch (ParserException e) {}
+        try {
+            Expression.compile("x(");
+            fail("Error expected");
+        } catch (ParserException e) {}
+    }
+
+    private double simpleEval(String expression) throws Exception {
+        return Expression.compile(expression).evaluate();
+    }
+}