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Fix: Apply absolute value logic in PluralRules #506

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Merged
axunonb merged 1 commit into from
Oct 24, 2025
Merged

Fix: Apply absolute value logic in PluralRules #506

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8 changes: 4 additions & 4 deletions src/SmartFormat.Tests/Extensions/PluralLocalizationFormatterTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -99,7 +99,7 @@ public void Test_Default()
new CultureInfo("en-US"),
"There {0:plural:is|are} {0} {0:plural:item|items} remaining",
new ExpectedResults {
{ -1, "There are -1 items remaining"},
{ -1, "There is -1 item remaining"},
{ 0, "There are 0 items remaining"},
{0.5m, "There are 0.5 items remaining"},
{ 1, "There is 1 item remaining"},
Expand All @@ -116,7 +116,7 @@ public void Test_English()
new CultureInfo("en-US"),
"There {0:plural:is|are} {0} {0:plural:item|items} remaining",
new ExpectedResults {
{ -1, "There are -1 items remaining"},
{ -1, "There is -1 item remaining"},
{ 0, "There are 0 items remaining"},
{0.5m, "There are 0.5 items remaining"},
{ 1, "There is 1 item remaining"},
Expand Down Expand Up @@ -184,7 +184,7 @@ public void Test_French_3words(int count, string expected)
Assert.That(actual, Is.EqualTo(string.Format(ci, expected, count)));
}

[TestCase(-1, "-")]
[TestCase(-1, "une personne")] // -1 is treated as 1 (singular)
[TestCase(0, "pas de personne")] // 0 is singular
[TestCase(1, "une personne")] // 1 is singular
[TestCase(2, "{0} personnes")] // 2 is plural
Expand Down Expand Up @@ -214,7 +214,7 @@ public void Test_Turkish()
new CultureInfo("tr"),
"Seçili {0:plural:nesneyi|nesneleri} silmek istiyor musunuz?",
new ExpectedResults {
{ -1, "Seçili nesneleri silmek istiyor musunuz?"},
{ -1, "Seçili nesneyi silmek istiyor musunuz?"}, // -1 is treated as 1 (singular)
{ 0, "Seçili nesneleri silmek istiyor musunuz?"},
{0.5m, "Seçili nesneleri silmek istiyor musunuz?"},
{ 1, "Seçili nesneyi silmek istiyor musunuz?"},
Expand Down
190 changes: 136 additions & 54 deletions src/SmartFormat/Utilities/PluralRules.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,6 @@

using System;
using System.Collections.Generic;
using System.Text.RegularExpressions;

namespace SmartFormat.Utilities;
#pragma warning disable S3776 // disable sonar cognitive complexity warnings
Expand Down Expand Up @@ -211,6 +210,7 @@ public static void RestoreDefault()

private static PluralRuleDelegate DualOneOther => (value, pluralWordsCount) =>
{
value = Math.Abs(value);
return pluralWordsCount switch {
2 => value == 1 ? 0 : 1,
3 => value switch {
Expand All @@ -224,10 +224,15 @@ public static void RestoreDefault()
}; // Dual: one (n == 1), other

private static PluralRuleDelegate DualWithZero =>
(value, pluralWordsCount) => value == 0 || value == 1 ? 0 : 1; // DualWithZero: one (n == 0..1), other
(value, pluralWordsCount) =>
{
value = Math.Abs(value);
return value == 0 || value == 1 ? 0 : 1;
}; // DualWithZero: one (n == 0..1), other

private static PluralRuleDelegate DualFromZeroToTwo => (value, pluralWordsCount) =>
{
value = Math.Abs(value);
if (pluralWordsCount == 2) return value is >= 0 and < 2 ? 0 : 1;

if (pluralWordsCount == 3) return GetWordsCount3Value(value);
Expand All @@ -239,6 +244,7 @@ public static void RestoreDefault()

private static int GetWordsCount3Value(decimal n)
{
n = Math.Abs(n);
return n switch
{
0 => 0,
Expand All @@ -249,6 +255,7 @@ private static int GetWordsCount3Value(decimal n)

private static int GetWordsCount4Value(decimal n)
{
n = Math.Abs(n);
return n switch
{
< 0 => 0,
Expand All @@ -258,37 +265,59 @@ private static int GetWordsCount4Value(decimal n)
};
}

private static PluralRuleDelegate TripleOneTwoOther => (value, pluralWordsCount) => value == 1 ? 0 : value == 2 ? 1 : 2; // Triple: one (n == 1), two (n == 2), other
private static PluralRuleDelegate TripleOneTwoOther => (value, pluralWordsCount) =>
{
value = Math.Abs(value);
return value == 1 ? 0 : value == 2 ? 1 : 2;
}; // Triple: one (n == 1), two (n == 2), other

private static PluralRuleDelegate RussianSerboCroatian => (value, pluralWordsCount) =>
value % 10 == 1 && value % 100 != 11 ? 0 : // one
(value % 10).BetweenWithoutFraction(2, 4) && !(value % 100).BetweenWithoutFraction(12, 14) ? 1 : // few
2; // Russian & Serbo-Croatian
{
value = Math.Abs(value);
return value % 10 == 1 && value % 100 != 11 ? 0 : // one
(value % 10).BetweenWithoutFraction(2, 4) && !(value % 100).BetweenWithoutFraction(12, 14) ? 1 : // few
2;
}; // Russian & Serbo-Croatian

private static PluralRuleDelegate Arabic => (value, pluralWordsCount) =>
value == 0 ? 0 : // zero
value == 1 ? 1 : // one
value == 2 ? 2 : // two
(value % 100).BetweenWithoutFraction(3, 10) ? 3 : // few
(value % 100).BetweenWithoutFraction(11, 99) ? 4 : // many
5; // other
{
value = Math.Abs(value);
return value == 0 ? 0 : // zero
value == 1 ? 1 : // one
value == 2 ? 2 : // two
(value % 100).BetweenWithoutFraction(3, 10) ? 3 : // few
(value % 100).BetweenWithoutFraction(11, 99) ? 4 : // many
5;
}; // other

private static PluralRuleDelegate Breton => (value, pluralWordsCount) =>
value switch
{
value = Math.Abs(value);
return value switch
{
0 => 0, // zero
1 => 1, // one
2 => 2, // two
3 => 3, // few
6 => 4, // many
_ => 5 // other
};
};
};

private static PluralRuleDelegate Czech => (value, pluralWordsCount) =>
value == 0 ? 0 : // zero
value == 1 ? 1 : // one
value.BetweenWithoutFraction(2, 4) ? 2 : // few
value % 1 == 0 ? 3 : // many
4; // other
{
value = Math.Abs(value);
return value == 0 ? 0 : // zero
value == 1 ? 1 : // one
value.BetweenWithoutFraction(2, 4) ? 2 : // few
value % 1 == 0 ? 3 : // many
4; // other
};

private static PluralRuleDelegate Welsh => (value, pluralWordsCount) =>
value switch
{
value = Math.Abs(value);
return value switch
{
0 => 0, // zero
1 => 1, // one
Expand All @@ -297,67 +326,120 @@ private static int GetWordsCount4Value(decimal n)
6 => 4, // many
_ => 5 // other
};
};
private static PluralRuleDelegate Manx => (value, pluralWordsCount) =>
(value % 10).BetweenWithoutFraction(1, 2) || value % 20 == 0
{
value = Math.Abs(value);
return (value % 10).BetweenWithoutFraction(1, 2) || value % 20 == 0
? 0
: // one
1;
};

private static PluralRuleDelegate Langi => (value, pluralWordsCount) =>
value switch
{
value = Math.Abs(value);
return value switch
{
0 => 0,
> 0 and < 2 => 1,
_ => 2
};
};

private static PluralRuleDelegate Lithuanian => (value, pluralWordsCount) =>
value % 10 == 1 && !(value % 100).BetweenWithoutFraction(11, 19) ? 0 : // one
(value % 10).BetweenWithoutFraction(2, 9) && !(value % 100).BetweenWithoutFraction(11, 19) ? 1 : // few
2;
{
value = Math.Abs(value);
return value % 10 == 1 && !(value % 100).BetweenWithoutFraction(11, 19) ? 0 : // one
(value % 10).BetweenWithoutFraction(2, 9) && !(value % 100).BetweenWithoutFraction(11, 19) ? 1 : // few
2;
};

private static PluralRuleDelegate Latvian => (value, pluralWordsCount) =>
value == 0 ? 0 : // zero
value % 10 == 1 && value % 100 != 11 ? 1 :
2;
{
value = Math.Abs(value);
return value == 0 ? 0 : // zero
value % 10 == 1 && value % 100 != 11 ? 1 :
2;
};

private static PluralRuleDelegate Macedonian => (value, pluralWordsCount) =>
value % 10 == 1 && value != 11
{
value = Math.Abs(value);
return value % 10 == 1 && value != 11
? 0
: // one
1;
};

private static PluralRuleDelegate Moldavian => (value, pluralWordsCount) =>
value == 1 ? 0 : // one
value == 0 || value != 1 && (value % 100).BetweenWithoutFraction(1, 19) ? 1 : // few
2;
{
value = Math.Abs(value);
return value == 1 ? 0 : // one
value == 0 || value != 1 && (value % 100).BetweenWithoutFraction(1, 19) ? 1 : // few
2;
};

private static PluralRuleDelegate Maltese => (value, pluralWordsCount) =>
value == 1 ? 0 : // one
value == 0 || (value % 100).BetweenWithoutFraction(2, 10) ? 1 : // few
(value % 100).BetweenWithoutFraction(11, 19) ? 2 : // many
3;
{
value = Math.Abs(value);
return value == 1 ? 0 : // one
value == 0 || (value % 100).BetweenWithoutFraction(2, 10) ? 1 : // few
(value % 100).BetweenWithoutFraction(11, 19) ? 2 : // many
3;
};

private static PluralRuleDelegate Polish => (value, pluralWordsCount) =>
value == 1 ? 0 : // one
(value % 10).BetweenWithoutFraction(2, 4) && !(value % 100).BetweenWithoutFraction(12, 14) ? 1 : // few
(value % 10).BetweenWithoutFraction(0, 1) || (value % 10).BetweenWithoutFraction(5, 9) || (value % 100).BetweenWithoutFraction(12, 14) ? 2 : // many
3;
{
value = Math.Abs(value);
return value == 1 ? 0 : // one
(value % 10).BetweenWithoutFraction(2, 4) && !(value % 100).BetweenWithoutFraction(12, 14) ? 1 : // few
(value % 10).BetweenWithoutFraction(0, 1) || (value % 10).BetweenWithoutFraction(5, 9) ||
(value % 100).BetweenWithoutFraction(12, 14) ? 2 : // many
3;
};

private static PluralRuleDelegate Romanian => (value, pluralWordsCount) =>
value == 1 ? 0 : // one
value == 0 || (value % 100).BetweenWithoutFraction(1, 19) ? 1 : // few
2;
{
value = Math.Abs(value);
return value == 1 ? 0 : // one
value == 0 || (value % 100).BetweenWithoutFraction(1, 19) ? 1 : // few
2;
};

private static PluralRuleDelegate Tachelhit => (value, pluralWordsCount) =>
value >= 0 && value <= 1 ? 0 : // one
value.BetweenWithoutFraction(2, 10) ? 1 : // few
2;
{
value = Math.Abs(value);
return value >= 0 && value <= 1 ? 0 : // one
value.BetweenWithoutFraction(2, 10) ? 1 : // few
2;
};

private static PluralRuleDelegate Slovak => (value, pluralWordsCount) =>
value == 1 ? 0 : // one
value.BetweenWithoutFraction(2, 4) ? 1 : // few
2;
{
value = Math.Abs(value);
return value == 1 ? 0 : // one
value.BetweenWithoutFraction(2, 4) ? 1 : // few
2;
};

private static PluralRuleDelegate Slovenian => (value, pluralWordsCount) =>
value % 100 == 1 ? 0 : // one
value % 100 == 2 ? 1 : // two
(value % 100).BetweenWithoutFraction(3, 4) ? 2 : // few
3;
{
value = Math.Abs(value);
return value % 100 == 1 ? 0 : // one
value % 100 == 2 ? 1 : // two
(value % 100).BetweenWithoutFraction(3, 4) ? 2 : // few
3;
};

private static PluralRuleDelegate CentralMoroccoTamazight => (value, pluralWordsCount) =>
value.BetweenWithoutFraction(0, 1) || value.BetweenWithoutFraction(11, 99)
{
value = Math.Abs(value);
return value.BetweenWithoutFraction(0, 1) || value.BetweenWithoutFraction(11, 99)
? 0
: // one
1;
};

/// <summary>
/// This delegate determines which singular or plural word should be chosen for the given quantity.
Expand Down