From 2a347e6d194f7a7b33eb0c233f88c214688e1716 Mon Sep 17 00:00:00 2001
From: Riccardo Azzolini <riccardo4096@gmail.com>
Date: Thu, 31 Jan 2019 13:10:02 +0100
Subject: [PATCH] Allow unary operators in power exponent

---
 .../warppi/math/rules/dsl/frontend/Parser.java |  4 ++--
 .../math/rules/dsl/frontend/ParserTest.java    | 18 ++++++++++++++----
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/core/src/main/java/it/cavallium/warppi/math/rules/dsl/frontend/Parser.java b/core/src/main/java/it/cavallium/warppi/math/rules/dsl/frontend/Parser.java
index b45a7163..98d7ffbd 100644
--- a/core/src/main/java/it/cavallium/warppi/math/rules/dsl/frontend/Parser.java
+++ b/core/src/main/java/it/cavallium/warppi/math/rules/dsl/frontend/Parser.java
@@ -149,11 +149,11 @@ public class Parser {
 		}
 	}
 
-	// power = ( function | primary ) , [ POWER , power ] ;
+	// power = ( function | primary ) , [ POWER , unary ] ;
 	private Pattern power() throws SyntaxException {
 		Pattern pat = functionOrPrimary();
 		if (match(POWER) != null) {
-			pat = new PowerPattern(pat, power());
+			pat = new PowerPattern(pat, unary());
 		}
 		return pat;
 	}
diff --git a/core/src/test/java/it/cavallium/warppi/math/rules/dsl/frontend/ParserTest.java b/core/src/test/java/it/cavallium/warppi/math/rules/dsl/frontend/ParserTest.java
index c2687541..9e8c1b85 100644
--- a/core/src/test/java/it/cavallium/warppi/math/rules/dsl/frontend/ParserTest.java
+++ b/core/src/test/java/it/cavallium/warppi/math/rules/dsl/frontend/ParserTest.java
@@ -190,13 +190,18 @@ public class ParserTest {
 				new Token(REDUCTION, "reduction", 0),
 				new Token(IDENTIFIER, "test", 0),
 				new Token(COLON, ":", 0),
+				new Token(NUMBER, "1", 0),
+				new Token(DIVIDE, "/", 0),
+				new Token(LEFT_PAREN, "(", 0),
 				new Token(IDENTIFIER, "x", 0),
 				new Token(TIMES, "*", 0),
 				new Token(IDENTIFIER, "x", 0),
+				new Token(RIGHT_PAREN, ")", 0),
 				new Token(ARROW, "->", 0),
 				new Token(LEFT_BRACKET, "[", 0),
 				new Token(IDENTIFIER, "x", 0),
 				new Token(POWER, "^", 0),
+				new Token(MINUS, "-", 0),
 				new Token(NUMBER, "2", 0),
 				new Token(RIGHT_BRACKET, "]", 0),
 				new Token(EOF, "", 0)
@@ -206,13 +211,18 @@ public class ParserTest {
 		final List<PatternRule> expected = Collections.singletonList(new PatternRule(
 				"test",
 				RuleType.REDUCTION,
-				new MultiplicationPattern(
-						new SubFunctionPattern("x"),
-						new SubFunctionPattern("x")
+				new DivisionPattern(
+						new NumberPattern(new BigDecimal(1)),
+						new MultiplicationPattern(
+								new SubFunctionPattern("x"),
+								new SubFunctionPattern("x")
+						)
 				),
 				new PowerPattern(
 						new SubFunctionPattern("x"),
-						new NumberPattern(new BigDecimal(2))
+						new NegativePattern(
+								new NumberPattern(new BigDecimal(2))
+						)
 				)
 		));
 		assertEquals(expected, parser.parse());