Multiplication between a value and a unit now has precedence.

Example, 3 m / 2 s = (3 m) / (2 s)
This change also makes "3m" a valid expression.

1 files changed, 35 insertions, 1 deletions

diff --git a/src/org/unitConverter/unit/UnitDatabase.java b/src/org/unitConverter/unit/UnitDatabase.java
index 5985c80..6a89b67 100644
--- a/src/org/unitConverter/unit/UnitDatabase.java
+++ b/src/org/unitConverter/unit/UnitDatabase.java
@@ -30,6 +30,7 @@ import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
+import java.util.Map.Entry;
 import java.util.NoSuchElementException;
 import java.util.Objects;
 import java.util.Set;
@@ -969,6 +970,21 @@ public final class UnitDatabase {
 	}
 
 	/**
+	 * Replacements done to *all* expression types
+	 */
+	private static final Map<Pattern, String> EXPRESSION_REPLACEMENTS = new HashMap<>();
+
+	static {
+		// place brackets around any expression of the form "number unit", with or without the space
+		EXPRESSION_REPLACEMENTS.put(Pattern.compile("((?:-?[1-9]\\d*|0)" // integer
+				+ "(?:\\.\\d+)?)" // optional decimal point with numbers after it
+				+ "\\s*" // optional space(s)
+				+ "([a-zA-Z]+)" // unit name
+				+ "(?!-?\\d)" // no number directly afterwards (avoids matching "1e3")
+		), "\\($1 $2\\)");
+	}
+
+	/**
 	 * A regular expression that separates names and expressions in unit files.
 	 */
 	private static final Pattern NAME_EXPRESSION = Pattern.compile("(\\S+)\\s+(\\S.*)");
@@ -1208,6 +1224,7 @@ public final class UnitDatabase {
 					"Error at line %d: Lines of a unit file must consist of a unit name, then spaces or tabs, then a unit expression.",
 					lineCounter));
 		final String name = lineMatcher.group(1);
+
 		final String expression = lineMatcher.group(2);
 
 		if (name.endsWith(" ")) {
@@ -1360,6 +1377,11 @@ public final class UnitDatabase {
 		// fix broken spaces
 		modifiedExpression = modifiedExpression.replaceAll(" +", " ");
 
+		// format expression
+		for (final Entry<Pattern, String> replacement : EXPRESSION_REPLACEMENTS.entrySet()) {
+			modifiedExpression = replacement.getKey().matcher(modifiedExpression).replaceAll(replacement.getValue());
+		}
+
 		return this.unitDimensionParser.parseExpression(modifiedExpression);
 	}
 
@@ -1445,6 +1467,13 @@ public final class UnitDatabase {
 		// fix broken spaces
 		modifiedExpression = modifiedExpression.replaceAll(" +", " ");
 
+		// format expression
+		for (final Entry<Pattern, String> replacement : EXPRESSION_REPLACEMENTS.entrySet()) {
+			modifiedExpression = replacement.getKey().matcher(modifiedExpression).replaceAll(replacement.getValue());
+		}
+
+		System.out.println(modifiedExpression);
+
 		return this.prefixExpressionParser.parseExpression(modifiedExpression);
 	}
 
@@ -1507,11 +1536,16 @@ public final class UnitDatabase {
 		// fix broken spaces
 		modifiedExpression = modifiedExpression.replaceAll(" +", " ");
 
+		// format expression
+		for (final Entry<Pattern, String> replacement : EXPRESSION_REPLACEMENTS.entrySet()) {
+			modifiedExpression = replacement.getKey().matcher(modifiedExpression).replaceAll(replacement.getValue());
+		}
+
 		// the previous operation breaks negative numbers, fix them!
 		// (i.e. -2 becomes - 2)
 		for (int i = 2; i < modifiedExpression.length(); i++) {
 			if (modifiedExpression.charAt(i) == '-'
-					&& Arrays.asList('+', '-', '*', '/', '^').contains(modifiedExpression.charAt(i - 2))) {
+					&& (i < 2 || Arrays.asList('+', '-', '*', '/', '^').contains(modifiedExpression.charAt(i - 2)))) {
 				// found a broken negative number
 				modifiedExpression = modifiedExpression.substring(0, i + 1) + modifiedExpression.substring(i + 2);
 			}