From f902fa2cc62c60aa614ef7efb60bde0d1c9d2e15 Mon Sep 17 00:00:00 2001
From: Patrick Spek <p.spek@tyil.nl>
Date: Mon, 5 Aug 2019 15:26:46 +0200
Subject: Rewrite String::Fold

---
 lib/String/Fold.pm6 | 95 +++++++++++++++++++++--------------------------------
 1 file changed, 37 insertions(+), 58 deletions(-)

(limited to 'lib/String/Fold.pm6')

diff --git a/lib/String/Fold.pm6 b/lib/String/Fold.pm6
index 2db1155..0bd2296 100644
--- a/lib/String/Fold.pm6
+++ b/lib/String/Fold.pm6
@@ -7,65 +7,55 @@ unit module String::Fold;
 #| Fold a string to contain no lines longer than the given width.
 sub fold (
 	#| The string to fold.
-	Str:D $string,
+	Str() $string,
 
 	#| The maximum width of lines in the text.
-	Int:D :$width where 0 < * = 80,
-
-	#| The number of spaces used to indent the text.
-	Int:D :$indent where -1 < * = 0,
+	Int() :$width where 0 < * = 79,
 
 	--> Str
 ) is export {
-	my Str @folded-lines = [];
-	my Str @current-words = [];
-
-	for $string.trim.lines -> $line {
-		# Nothing to do if the line is less than the maximum width.
-		if ($line.chars <= $width) {
-			@folded-lines.append($line);
-			next;
-		}
+	my @paragraphs;
 
-		# Work through each word on the line and fold them to the maximum width.
-		for $line.comb(/\S+/) -> $word {
-			if (new-line-length(@current-words, $word, $indent) <= $width) {
-				@current-words.append($word);
-				next;
+	for $string.split("\n\n") -> $paragraph {
+		my @lines;
+		my $current-line = 0;
+
+		for $paragraph.lines.join(" ").words -> $word {
+			# If this word would make the line too long, go to the next line.
+			if (@lines[$current-line].&line-length + $word.chars > $width) {
+				$current-line++;
 			}
 
-			@folded-lines.append(@current-words.join(" "));
-			@current-words = [$word];
+			# Append the current word to the line.
+			@lines[$current-line].append($word);
 		}
 
-		# Clean up the current list of words.
-		@folded-lines.append(@current-words.join(" "));
-		@current-words = [];
+		@paragraphs.append(@lines.join("\n"));
 	}
 
-	# Add the last line if we have any leftover current words.
-	@folded-lines.push(@current-words.join(" ")) if @current-words;
-
-	return @folded-lines>>.indent($indent).join("\n");
+	@paragraphs.join("\n\n");
 }
 
-#| Calculate the total line length of a would-be line.
-sub new-line-length (
-	Str:D @words,
-	Str:D $new-word,
-	Int:D $indent-width,
+#| Get the length of a line array. If the array does not exist yet, it is
+#| clearly empty, and this sub returns 0.
+multi sub line-length (
+	Any,
+
 	--> Int
 ) {
-	my Int $chars = 0;
-
-	# Get the number of characters in each word.
-	$chars += [+] @words>>.chars;
+	0
+}
 
-	$chars += @words.elems; # Spaces inbetween the words.
-	$chars += $new-word.chars;
-	$chars += $indent-width;
+#| Get the length of a line array. This counts the characters of all words in
+#| the array, and adds up the number of spaces required for it to be a human
+#| representable line.
+multi sub line-length (
+	#| The line array, containing any number of words.
+	@line,
 
-	$chars;
+	--> Int
+) {
+	@line.map(*.chars).sum + @line.elems
 }
 
 =begin pod
@@ -76,12 +66,12 @@ sub new-line-length (
 
 =head1 SYNOPSIS
 
-fold(Str:D $, Int:D :$width, Int:D :$indent);
+fold(Str:D $, Int:D :$width);
 
 =head1 DESCRIPTION
 
-Fold a C<Str> to a given width. Accepts a C<:$width>N<Defaults to C<80>> and a
-C<:$indent>N<Defaults to C<0>>.
+Fold a C<Str> to a given width. Accepts a C<:$width>N<Defaults to C<79>>
+argument.
 
 =head1 EXAMPLES
 
@@ -94,7 +84,7 @@ my Str $folded = fold(slurp("some-text-file"));
 =end input
 
 This will yield a folded string in C<$folded>. The input file will have all its
-lines folded to a maximum width of 80 characters.
+lines folded to a maximum width of 79 characters.
 
 =head2 Folding at a custom width
 
@@ -104,19 +94,8 @@ use String::Fold;
 my Str $folded = slurp("some-text-file").&fold(:width(40));
 =end input
 
-This will yield a string folded at 40 characters, instead of the default of 80
-characters. Any number higher that C<0> is accepted.
-
-=head2 Indented block
-
-=begin input
-use String::Fold;
-
-my Str $indented = slurp("some-text-file").&fold(:indent(8));
-=end input
-
-This will yield a string folded at 80 characters (the default), and indented by
-8 spaces.
+This will yield a string folded at 40 characters, instead of the default of 79
+characters. Any number higher than C<0> is accepted.
 
 =end pod
 
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