english language formatting stuff

english.d

@@ -0,0 +1,121 @@
+module arsd.english;
+
+string numberToEnglish(long number) {
+	string word;
+	if(number == 0)
+		return "zero";
+
+	if(number < 0) {
+		word = "negative";
+		number = -number;
+	}
+
+	while(number) {
+		if(number < 100) {
+			if(number < singleWords.length) {
+				word ~= singleWords[cast(int) number];
+				break;
+			} else {
+				auto tens = number / 10;
+				word ~= tensPlaceWords[cast(int) tens];
+				number = number % 10;
+				if(number)
+					word ~= "-";
+			}
+		} else if(number < 1000) {
+			auto hundreds = number / 100;
+			word ~= onesPlaceWords[cast(int) hundreds] ~ " hundred";
+			number = number % 100;
+			if(number)
+				word ~= " and ";
+		} else if(number < 1000000) {
+			auto thousands = number / 1000;
+			word ~= numberToEnglish(thousands) ~ " thousand";
+			number = number % 1000;
+			if(number)
+				word ~= ", ";
+		} else if(number < 1_000_000_000) {
+			auto millions = number / 1000000;
+			word ~= numberToEnglish(millions) ~ " million";
+			number = number % 1000000;
+			if(number)
+				word ~= ", ";
+		} else if(number < 1_000_000_000_000) {
+			auto n = number / 1000000000;
+			word ~= numberToEnglish(n) ~ " billion";
+			number = number % 1000000000;
+			if(number)
+				word ~= ", ";
+		} else if(number < 1_000_000_000_000_000) {
+			auto n = number / 1000000000000;
+			word ~= numberToEnglish(n) ~ " trillion";
+			number = number % 1000000000000;
+			if(number)
+				word ~= ", ";
+		} else {
+			import std.conv;
+			return to!string(number);
+		}
+	}
+
+	return word;
+}
+
+unittest {
+	assert(numberToEnglish(1) == "one");
+	assert(numberToEnglish(5) == "five");
+	assert(numberToEnglish(13) == "thirteen");
+	assert(numberToEnglish(54) == "fifty-four");
+	assert(numberToEnglish(178) == "one hundred and seventy-eight");
+	assert(numberToEnglish(592) == "five hundred and ninety-two");
+	assert(numberToEnglish(1234) == "one thousand, two hundred and thirty-four");
+	assert(numberToEnglish(10234) == "ten thousand, two hundred and thirty-four");
+	assert(numberToEnglish(105234) == "one hundred and five thousand, two hundred and thirty-four");
+}
+
+enum onesPlaceWords = [
+	"zero",
+	"one",
+	"two",
+	"three",
+	"four",
+	"five",
+	"six",
+	"seven",
+	"eight",
+	"nine",
+];
+
+enum singleWords = onesPlaceWords ~ [
+	"ten",
+	"eleven",
+	"twelve",
+	"thirteen",
+	"fourteen",
+	"fifteen",
+	"sixteen",
+	"seventeen",
+	"eighteen",
+	"nineteen",
+];
+
+enum tensPlaceWords = [
+	null,
+	"ten",
+	"twenty",
+	"thirty",
+	"forty",
+	"fifty",
+	"sixty",
+	"seventy",
+	"eighty",
+	"ninety",
+];
+
+/*
+void main() {
+	import std.stdio;
+	foreach(i; 3433000 ..3433325)
+	writeln(numberToEnglish(i));
+}
+*/