1 files changed, 102 insertions, 0 deletions
diff --git a/examples/wrap/wrap.tm b/examples/wrap/wrap.tm
new file mode 100644
index 00000000..54198193
--- /dev/null
+++ b/examples/wrap/wrap.tm
@@ -0,0 +1,102 @@
+HELP := "
+    wrap: A tool for wrapping lines of text
+
+    usage: wrap [--help] [files...] [--width=80] [--inplace=no] [--min_split=3] [--no-rewrap] [--hyphen='-']
+        --help: Print this message and exit
+        [files...]: The files to wrap (stdin is used if no files are provided)
+        --width=N: The width to wrap the text
+        --inplace: Whether or not to perform the modification in-place or print the output
+        --min-split=N: The minimum amount of text on either end of a hyphenation split
+        --rewrap|--no-rewrap: Whether to rewrap text that is already wrapped or only split long lines
+        --hyphen='-': The text to use for hyphenation
+"
+
+UNICODE_HYPHEN := \{hyphen}
+
+func unwrap(text:Text, preserve_paragraphs=yes, hyphen=UNICODE_HYPHEN)->Text:
+    if preserve_paragraphs:
+        paragraphs := text:split($/{2+ nl}/)
+        if paragraphs.length > 1:
+            return \n\n:join([unwrap(p, hyphen=hyphen, preserve_paragraphs=no) for p in paragraphs])
+
+    return text:replace($/$(hyphen)$(\n)/, "")
+
+func wrap(text:Text, width:Int, min_split=3, hyphen="-")->Text:
+    if width <= 0:
+        fail("Width must be a positive integer, not $width")
+
+    if 2*min_split - hyphen.length > width:
+        fail("
+            Minimum word split length ($min_split) is too small for the given wrap width ($width)!
+
+            I can't fit a $(2*min_split - hyphen.length)-wide word on a line without splitting it,
+        ... and I can't split it without splitting into chunks smaller than $min_split.
+        ")
+
+    lines := [:Text]
+    line := ""
+    for word in text:split($/{whitespace}/):
+        letters := word:split()
+        skip if letters.length == 0
+
+        while not _can_fit_word(line, letters, width):
+            line_space := width - line.length
+            if line != "": line_space -= 1
+
+            if min_split > 0 and line_space >= min_split + hyphen.length and letters.length >= 2*min_split:
+                # Split word with a hyphen:
+                split := line_space - hyphen.length
+                split = split _max_ min_split
+                split = split _min_ (letters.length - min_split)
+                if line != "": line ++= " "
+                line ++= ((++) letters:to(split)) ++ hyphen
+                letters = letters:from(split + 1)
+            else if line == "":
+                # Force split word without hyphenation:
+                if line != "": line ++= " "
+                line ++= ((++) letters:to(line_space))
+                letters = letters:from(line_space + 1)
+            else:
+                pass # Move to next line
+
+            lines:insert(line)
+            line = ""
+
+        if letters.length > 0:
+            if line != "": line ++= " "
+            line ++= (++) letters
+
+    if line != "":
+        lines:insert(line)
+
+    return \n:join(lines)
+
+func _can_fit_word(line:Text, letters:[Text], width:Int; inline)->Bool:
+    if line == "":
+        return letters.length <= width
+    else:
+        return line.length + 1 + letters.length <= width
+
+func main(files:[Path], width=80, inplace=no, min_split=3, rewrap=yes, hyphen=UNICODE_HYPHEN):
+    if files.length == 0:
+        files = [(/dev/stdin)]
+
+    for file in files:
+        text := file:read():or_exit("Could not read file: $(file.text_content)")
+
+        if rewrap:
+            text = unwrap(text)
+
+        out := if file:is_file() and inplace:
+            file
+        else:
+            (/dev/stdout)
+
+        first := yes
+        wrapped_paragraphs := [:Text]
+        for paragraph in text:split($/{2+ nl}/):
+            wrapped_paragraphs:insert(
+                wrap(paragraph, width=width, min_split=min_split, hyphen=hyphen)
+            )
+
+        out:write(\n\n:join(wrapped_paragraphs) ++ \n)