Parse negative numbers in Norwegian (and 59 other languages) (#290)

The DecimalFormatSymbols for Norwegian and 59 other languages use the
minus-sign (unicode 8722) instead of the hyphen-minus sign (ascii 45).

While technically correct, Gherkin is written on regular keyboards and
there is no practical way to write a minus-sign. By patching the
`DecimalFormatSymbols` with a regular minus sign we solve this problem.

Additionally, for the same reason, the non-breaking space (ascii 160)
and right single quotation mark (unicode 8217) for thousands separators
are also patched with either a period or colon.

Fixes: #287

Author: mpkorstanje

CHANGELOG.md

@@ -6,7 +6,11 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased]
+### Added
+- [Java] Assume numbers use either a comma or period for the thousands separator instead of non-breaking spaces. ([#290](https://github.com/cucumber/cucumber-expressions/pull/290)) 
+
 ### Fixed
+- [Java] Parse negative numbers in Norwegian (and 59 other languages) ([#290](https://github.com/cucumber/cucumber-expressions/pull/290))
 - [Python] Remove support for Python 3.7 and extend support to 3.12 ([#280](https://github.com/cucumber/cucumber-expressions/pull/280))
 - [Python] The `ParameterType` constructor's `transformer` should be optional ([#288](https://github.com/cucumber/cucumber-expressions/pull/288))
 

README.md

@@ -65,14 +65,35 @@ the following built-in parameter types:
 | `{short}`       | Matches the same as `{int}`, but converts to a 16 bit signed integer if the platform supports it. |
 | `{long}`        | Matches the same as `{int}`, but converts to a 64 bit signed integer if the platform supports it. |
 
-### Cucumber-JVM
+### Java
+
+### The Anonymous Parameter
 
 The *anonymous* parameter type will be converted to the parameter type of the step definition using an object mapper.
 Cucumber comes with a built-in object mapper that can handle all numeric types as well as. `Enum`.
 
-To automatically convert to other types it is recommended to install an object mapper. See [configuration](https://cucumber.io/docs/cucumber/configuration)
+To automatically convert to other types it is recommended to install an object mapper. See [cucumber-java - Default Transformers](https://github.com/cucumber/cucumber-jvm/tree/main/cucumber-java#default-transformers)
 to learn how.
 
+### Number formats
+
+Java supports parsing localised numbers. I.e. in your English feature file you
+can format a-thousand-and-one-tenth as '1,000.1; while in French you would format it
+as '1.000,1'. 
+
+Parsing is facilitated by Javas [`DecimalFormat`](https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/text/DecimalFormat.html)
+and includes support for the scientific notation. Unfortunately the default
+localisation include symbols that can not be easily written on a regular
+keyboard. So a few substitutions are made:
+
+ * The minus sign is always hyphen-minus - (ascii 45).
+ * If the decimal separator is a period (. ascii 46) the thousands separator is a comma (, ascii 44).
+   So '1 000.1' and '1’000.1' should always be written as '1,000.1'. 
+ * If the decimal separator is a comma (, ascii 44) the thousands separator is a period (. ascii 46).
+   So '1 000,1' or '1’000,1' should always be written as '1.000,1'.
+
+If support for your preferred language could be improved, please create an issue!
+
 ### Custom Parameter types
 
 Cucumber Expressions can be extended so they automatically convert

java/src/main/java/io/cucumber/cucumberexpressions/KeyboardFriendlyDecimalFormatSymbols.java

@@ -0,0 +1,34 @@
+package io.cucumber.cucumberexpressions;
+
+import java.text.DecimalFormatSymbols;
+import java.util.Locale;
+
+/**
+ * A set of localized decimal symbols that can be written on a regular keyboard.
+ * <p>
+ * Note quite complete, feel free to make a suggestion.
+ */
+class KeyboardFriendlyDecimalFormatSymbols {
+
+    static DecimalFormatSymbols getInstance(Locale locale) {
+        DecimalFormatSymbols symbols = DecimalFormatSymbols.getInstance(locale);
+
+        // Replace the minus sign with minus-hyphen as available on most keyboards.
+        if (symbols.getMinusSign() == '\u2212') {
+            symbols.setMinusSign('-');
+        }
+
+        if (symbols.getDecimalSeparator() == '.') {
+            // For locales that use the period as the decimal separator
+            // always use the comma for thousands. The alternatives are
+            // not available on a keyboard
+            symbols.setGroupingSeparator(',');
+        } else if (symbols.getDecimalSeparator() == ',') {
+            // For locales that use the comma as the decimal separator
+            // always use the period for thousands. The alternatives are
+            // not available on a keyboard
+            symbols.setGroupingSeparator('.');
+        }
+        return symbols;
+    }
+}

java/src/main/java/io/cucumber/cucumberexpressions/NumberParser.java

@@ -2,6 +2,7 @@
 
 import java.math.BigDecimal;
 import java.text.DecimalFormat;
+import java.text.DecimalFormatSymbols;
 import java.text.NumberFormat;
 import java.text.ParseException;
 import java.util.Locale;
@@ -14,6 +15,8 @@ final class NumberParser {
         if (numberFormat instanceof DecimalFormat) {
             DecimalFormat decimalFormat = (DecimalFormat) numberFormat;
             decimalFormat.setParseBigDecimal(true);
+            DecimalFormatSymbols symbols = KeyboardFriendlyDecimalFormatSymbols.getInstance(locale);
+            decimalFormat.setDecimalFormatSymbols(symbols);
         }
     }
 

java/src/main/java/io/cucumber/cucumberexpressions/ParameterTypeRegistry.java

@@ -58,7 +58,7 @@ private ParameterTypeRegistry(ParameterByTypeTransformer defaultParameterTransfo
         this.internalParameterTransformer = defaultParameterTransformer;
         this.defaultParameterTransformer = defaultParameterTransformer;
 
-        DecimalFormatSymbols numberFormat = DecimalFormatSymbols.getInstance(locale);
+        DecimalFormatSymbols numberFormat = KeyboardFriendlyDecimalFormatSymbols.getInstance(locale);
 
         List<String> localizedFloatRegexp = singletonList(FLOAT_REGEXPS
                 .replace("{decimal}", "" + numberFormat.getDecimalSeparator())

java/src/test/java/io/cucumber/cucumberexpressions/KeyboardFriendlyDecimalFormatSymbolsTest.java

@@ -0,0 +1,98 @@
+package io.cucumber.cucumberexpressions;
+
+import org.junit.jupiter.api.Test;
+
+import java.text.DecimalFormatSymbols;
+import java.util.AbstractMap.SimpleEntry;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Locale;
+import java.util.function.Function;
+import java.util.stream.Stream;
+
+import static java.util.Comparator.comparing;
+import static java.util.stream.Collectors.groupingBy;
+import static java.util.stream.Collectors.toList;
+
+class KeyboardFriendlyDecimalFormatSymbolsTest {
+
+    @Test
+    void listMinusSigns(){
+        System.out.println("Original minus signs:");
+        listMinusSigns(DecimalFormatSymbols::getInstance);
+        System.out.println();
+        System.out.println("Friendly minus signs:");
+        listMinusSigns(KeyboardFriendlyDecimalFormatSymbols::getInstance);
+        System.out.println();
+    }
+
+    private static void listMinusSigns(Function<Locale, DecimalFormatSymbols> supplier) {
+        getAvailableLocalesAsStream()
+                .collect(groupingBy(locale -> supplier.apply(locale).getMinusSign()))
+                .forEach((c, locales) -> System.out.println(render(c) + " " + render(locales)));
+    }
+
+    @Test
+    void listDecimalAndGroupingSeparators(){
+        System.out.println("Original decimal and group separators:");
+        listDecimalAndGroupingSeparators(DecimalFormatSymbols::getInstance);
+        System.out.println();
+        System.out.println("Friendly decimal and group separators:");
+        listDecimalAndGroupingSeparators(KeyboardFriendlyDecimalFormatSymbols::getInstance);
+        System.out.println();
+    }
+
+    private static void listDecimalAndGroupingSeparators(Function<Locale, DecimalFormatSymbols> supplier) {
+        getAvailableLocalesAsStream()
+                .collect(groupingBy(locale -> {
+                    DecimalFormatSymbols symbols = supplier.apply(locale);
+                    return new SimpleEntry<>(symbols.getDecimalSeparator(), symbols.getGroupingSeparator());
+                }))
+                .entrySet()
+                .stream()
+                .sorted(comparing(entry -> entry.getKey().getKey()))
+                .forEach((entry) -> {
+                    SimpleEntry<Character, Character> characters = entry.getKey();
+                    List<Locale> locales = entry.getValue();
+                    System.out.println(render(characters.getKey()) + " " + render(characters.getValue()) + " " + render(locales));
+                });
+    }
+
+    @Test
+    void listExponentSigns(){
+        System.out.println("Original exponent signs:");
+        listExponentSigns(DecimalFormatSymbols::getInstance);
+        System.out.println();
+        System.out.println("Friendly exponent signs:");
+        listExponentSigns(KeyboardFriendlyDecimalFormatSymbols::getInstance);
+        System.out.println();
+    }
+
+    private static void listExponentSigns(Function<Locale, DecimalFormatSymbols> supplier) {
+        getAvailableLocalesAsStream()
+                .collect(groupingBy(locale -> supplier.apply(locale).getExponentSeparator()))
+                .forEach((s, locales) -> {
+                    if (s.length() == 1) {
+                        System.out.println(render(s.charAt(0)) + " " + render(locales));
+                    } else {
+                        System.out.println(s + " " + render(locales));
+                    }
+                });
+    }
+
+    private static Stream<Locale> getAvailableLocalesAsStream() {
+        return Arrays.stream(DecimalFormatSymbols.getAvailableLocales());
+    }
+
+    private static String render(Character character) {
+        return character + " (" + (int) character + ")";
+    }
+
+    private static String render(List<Locale> locales) {
+        return locales.size() + ": " + locales.stream()
+                .sorted(comparing(Locale::getDisplayName))
+                .map(Locale::getDisplayName)
+                .collect(toList());
+    }
+
+}

java/src/test/java/io/cucumber/cucumberexpressions/NumberParserTest.java

@@ -5,36 +5,70 @@
 import java.math.BigDecimal;
 import java.util.Locale;
 
+import static java.util.Locale.forLanguageTag;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-public class NumberParserTest {
+class NumberParserTest {
 
     private final NumberParser english = new NumberParser(Locale.ENGLISH);
     private final NumberParser german = new NumberParser(Locale.GERMAN);
     private final NumberParser canadianFrench = new NumberParser(Locale.CANADA_FRENCH);
+    private final NumberParser norwegian = new NumberParser(forLanguageTag("no"));
+    private final NumberParser canadian = new NumberParser(Locale.CANADA);
 
     @Test
-    public void can_parse_float() {
+    void can_parse_float() {
         assertEquals(1042.2f, english.parseFloat("1,042.2"), 0);
-        assertEquals(1042.2f, german.parseFloat( "1.042,2"), 0);
-        assertEquals(1042.2f, canadianFrench.parseFloat( "1\u00A0042,2"), 0);
+        assertEquals(1042.2f, canadian.parseFloat("1,042.2"), 0);
+
+        assertEquals(1042.2f, german.parseFloat("1.042,2"), 0);
+        assertEquals(1042.2f, canadianFrench.parseFloat("1.042,2"), 0);
+        assertEquals(1042.2f, norwegian.parseFloat("1.042,2"), 0);
     }
 
     @Test
-    public void can_parse_double() {
+    void can_parse_double() {
         assertEquals(1042.000000000000002, english.parseDouble("1,042.000000000000002"), 0);
-        assertEquals(1042.000000000000002, german.parseDouble( "1.042,000000000000002"), 0);
-        assertEquals(1042.000000000000002, canadianFrench.parseDouble( "1\u00A0042,000000000000002"), 0);
+        assertEquals(1042.000000000000002, canadian.parseDouble("1,042.000000000000002"), 0);
+
+        assertEquals(1042.000000000000002, german.parseDouble("1.042,000000000000002"), 0);
+        assertEquals(1042.000000000000002, canadianFrench.parseDouble("1.042,000000000000002"), 0);
+        assertEquals(1042.000000000000002, norwegian.parseDouble("1.042,000000000000002"), 0);
     }
 
     @Test
-    public void can_parse_big_decimals() {
+    void can_parse_big_decimals() {
         assertEquals(new BigDecimal("1042.0000000000000000000002"), english.parseBigDecimal("1,042.0000000000000000000002"));
-        assertEquals(new BigDecimal("1042.0000000000000000000002"), german.parseBigDecimal( "1.042,0000000000000000000002"));
-        assertEquals(new BigDecimal("1042.0000000000000000000002"), canadianFrench.parseBigDecimal( "1\u00A0042,0000000000000000000002"));
+        assertEquals(new BigDecimal("1042.0000000000000000000002"), canadian.parseBigDecimal("1,042.0000000000000000000002"));
+
+        assertEquals(new BigDecimal("1042.0000000000000000000002"), german.parseBigDecimal("1.042,0000000000000000000002"));
+        assertEquals(new BigDecimal("1042.0000000000000000000002"), canadianFrench.parseBigDecimal("1.042,0000000000000000000002"));
+        assertEquals(new BigDecimal("1042.0000000000000000000002"), norwegian.parseBigDecimal("1.042,0000000000000000000002"));
+    }
+
+    @Test
+    void can_parse_negative() {
+        assertEquals(-1042.2f, english.parseFloat("-1,042.2"), 0);
+        assertEquals(-1042.2f, canadian.parseFloat("-1,042.2"), 0);
+
+        assertEquals(-1042.2f, german.parseFloat("-1.042,2"), 0);
+        assertEquals(-1042.2f, canadianFrench.parseFloat("-1.042,2"), 0);
+        assertEquals(-1042.2f, norwegian.parseFloat("-1.042,2"), 0);
+    }
 
+    @Test
+    void can_parse_exponents() {
         assertEquals(new BigDecimal("100"), english.parseBigDecimal("1.00E2"));
+        assertEquals(new BigDecimal("100"), canadian.parseBigDecimal("1.00e2"));
+        assertEquals(new BigDecimal("100"), german.parseBigDecimal("1,00E2"));
+        assertEquals(new BigDecimal("100"), canadianFrench.parseBigDecimal("1,00E2"));
+        assertEquals(new BigDecimal("100"), norwegian.parseBigDecimal("1,00E2"));
+
         assertEquals(new BigDecimal("0.01"), english.parseBigDecimal("1E-2"));
+        assertEquals(new BigDecimal("0.01"), canadian.parseBigDecimal("1e-2"));
+        assertEquals(new BigDecimal("0.01"), german.parseBigDecimal("1E-2"));
+        assertEquals(new BigDecimal("0.01"), canadianFrench.parseBigDecimal("1E-2"));
+        assertEquals(new BigDecimal("0.01"), norwegian.parseBigDecimal("1E-2"));
     }
 
 }

java/src/test/java/io/cucumber/cucumberexpressions/ParameterTypeRegistryTest.java

@@ -171,8 +171,19 @@ public void parse_decimal_numbers_in_canadian_french() {
         ExpressionFactory factory = new ExpressionFactory(new ParameterTypeRegistry(Locale.CANADA_FRENCH));
         Expression expression = factory.createExpression("{bigdecimal}");
 
-        assertThat(expression.match("1\u00A0000,1").get(0).getValue(), is(new BigDecimal("1000.1")));
-        assertThat(expression.match("1\u00A0000\u00A0000,1").get(0).getValue(), is(new BigDecimal("1000000.1")));
+        assertThat(expression.match("1.000,1").get(0).getValue(), is(new BigDecimal("1000.1")));
+        assertThat(expression.match("1.000.000,1").get(0).getValue(), is(new BigDecimal("1000000.1")));
+        assertThat(expression.match("-1,1").get(0).getValue(), is(new BigDecimal("-1.1")));
+        assertThat(expression.match("-,1E1").get(0).getValue(), is(new BigDecimal("-1")));
+    }
+
+    @Test
+    public void parse_decimal_numbers_in_norwegian() {
+        ExpressionFactory factory = new ExpressionFactory(new ParameterTypeRegistry(Locale.forLanguageTag("no")));
+        Expression expression = factory.createExpression("{bigdecimal}");
+
+        assertThat(expression.match("1.000,1").get(0).getValue(), is(new BigDecimal("1000.1")));
+        assertThat(expression.match("1.000.000,1").get(0).getValue(), is(new BigDecimal("1000000.1")));
         assertThat(expression.match("-1,1").get(0).getValue(), is(new BigDecimal("-1.1")));
         assertThat(expression.match("-,1E1").get(0).getValue(), is(new BigDecimal("-1")));
     }