Fix #284 - Implicit mul and exponentiation cannot be parsed

sys27 · Aug 29, 2020 · b7ab274 · b7ab274
1 parent 59e04ad
commit b7ab274
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Showing 2 changed files with 40 additions and 2 deletions.
diff --git a/xFunc.Maths/Parser.cs b/xFunc.Maths/Parser.cs
@@ -518,8 +518,7 @@ private IExpression MulImplicitLeftUnary(TokenReader tokenReader)
             var number = Number(tokenReader);
             if (number != null)
             {
-                var rightUnary = Function(tokenReader) ??
-                                 Variable(tokenReader) ??
+                var rightUnary = MulImplicitExponentiation(tokenReader) ??
                                  ParenthesesExpression(tokenReader) ??
                                  Matrix(tokenReader) ??
                                  Vector(tokenReader);
@@ -539,6 +538,23 @@ private IExpression MulImplicitLeftUnary(TokenReader tokenReader)
             return null;
         }
 
+        private IExpression MulImplicitExponentiation(TokenReader tokenReader)
+        {
+            var left = Function(tokenReader) ??
+                       Variable(tokenReader);
+            if (left == null)
+                return null;
+
+            var @operator = tokenReader.Operator(OperatorToken.Exponentiation);
+            if (@operator == null)
+                return left;
+
+            var right = Exponentiation(tokenReader) ??
+                        throw new ParseException(Resource.ExponentParseException);
+
+            return CreateExponentiation(left, right);
+        }
+
         private IExpression LeftUnary(TokenReader tokenReader)
         {
             var token = (tokenReader.Operator(OperatorToken.Not) ??

diff --git a/xFunc.Tests/ParserTests/ParserTest.cs b/xFunc.Tests/ParserTests/ParserTest.cs
@@ -2151,5 +2151,27 @@ public void ParseCosWithoutOperator()
 
             ParseErrorTest(tokens);
         }
+
+        [Fact]
+        public void ImplicitMulAndPower()
+        {
+            var tokens = Builder()
+                .Number(2)
+                .Id("sin")
+                .OpenParenthesis()
+                .VariableX()
+                .CloseParenthesis()
+                .Operation(OperatorToken.Exponentiation)
+                .Number(2)
+                .Tokens;
+
+            var exp = parser.Parse(tokens);
+            var expected = new Mul(
+                Number.Two,
+                new Pow(new Sin(Variable.X), Number.Two)
+            );
+
+            Assert.Equal(expected, exp);
+        }
     }
 }