Render the annotated document in a certain style. Styles not set in the annotation will use the style of the surrounding document, or the terminal’s default if none has been set yet.

style = color Green <> bold
styledDoc = annotate style "hello world"

The 8 ANSI terminal colors.

Style the foreground with a vivid color.

Style the foreground with a dull color.

Style the background with a vivid color.

Style the background with a dull color.

Render in bold.

Render in italics.

Render underlined.

Dull or vivid coloring, as supported by ANSI terminals.

(renderLazy doc) takes the output doc from a rendering function and transforms it to lazy text, including ANSI styling directives for things like colorization.

ANSI color information will be discarded by this function unless you are running on a Unix-like operating system. This is due to a technical limitation in Windows ANSI support.

With a bit of trickery to make the ANSI codes printable, here is an example that would render colored in an ANSI terminal:

>>> let render = TL.putStrLn . TL.replace "\ESC" "\\e" . renderLazy . layoutPretty defaultLayoutOptions
>>> let doc = annotate (color Red) ("red" <+> align (vsep [annotate (color Blue <> underlined) ("blue+u" <+> annotate bold "bold" <+> "blue+u"), "red"]))
>>> render (unAnnotate doc)
red blue+u bold blue+u
    red
>>> render doc
\e[0;91mred \e[0;94;4mblue+u \e[0;94;1;4mbold\e[0;94;4m blue+u\e[0;91m
    red\e[0m

Run the above via echo -e ... in your terminal to see the coloring.

(renderStrict sdoc) takes the output sdoc from a rendering and transforms it to strict text.

(renderIO h sdoc) writes sdoc to the handle h.

>>> let render = renderIO System.IO.stdout . layoutPretty defaultLayoutOptions
>>> let doc = annotate (color Red) ("red" <+> align (vsep [annotate (color Blue <> underlined) ("blue+u" <+> annotate bold "bold" <+> "blue+u"), "red"]))

We render the unAnnotated version here, since the ANSI codes don’t display well in Haddock,

>>> render (unAnnotate doc)
red blue+u bold blue+u
    red

This function behaves just like

renderIO h sdoc = hPutStr h (renderLazy sdoc)

but will not generate any intermediate text, rendering directly to the handle.

(putDoc doc) prettyprints document doc to standard output using defaultLayoutOptions.

>>> putDoc ("hello" <+> "world")
hello world

putDoc = hPutDoc stdout

Like putDoc, but instead of using stdout, print to a user-provided handle, e.g. a file or a socket using defaultLayoutOptions.

main = withFile "someFile.txt" (\h -> hPutDoc h (vcat ["vertical", "text"]))

hPutDoc h doc = renderIO h (layoutPretty defaultLayoutOptions doc)