Add documentation to README

Author: tarleb

README.md

@@ -17,7 +17,316 @@ Lua module wrapping the [doclayout] Haskell package.
 [Stackage Nightly badge]: http://stackage.org/package/hslua-module-doclayout/badge/nightly
 [License badge]: https://img.shields.io/badge/license-MIT-blue.svg
 
-# License
+
+Example
+-------
+
+``` haskell
+loadProg :: Lua Status
+loadProg = do
+  openlibs
+  preloadModule "doclayout"
+  dostring $ unlines
+    [ "doc = require 'doclayout'"
+    , "local example_doc = (doc.literal 'Line' + 'One')"
+    , "                 // (doc.literal 'Line' + 'Two')"
+    , "-- prints:"
+    , "-- Line One"
+    , "--"
+    , "-- Line Two"
+    , "print(doc.render(example_doc))"
+    , ""
+    , "-- prints:"
+    , "-- Line"
+    , "-- One"
+    , "--"
+    , "-- Line"
+    , "-- Two"
+    , "local columns = 5"
+    , "print(doc.render(example_doc, columns))"
+    ]
+```
+
+
+Documentation
+-------------
+
+### Functions
+
+#### render
+
+`render (doc[, colwidth])`
+
+Render the `Doc` using the given column width.
+
+Parameters:
+
+`doc`
+:   Doc to render
+
+`colwidth`
+:   Maximum number of characters per line
+
+#### concat
+
+`concat (docs[, sep])`
+
+Concatenate the given `Doc`s, interspersing `sep` if specified.
+
+Parameters:
+
+`docs`
+:   List of `Doc`s
+
+`sep`
+:   Separator `Doc`
+
+### Doc construction
+
+All functions return a fresh `Doc` element.
+
+#### after_break
+
+`after_break`
+
+Creates a `Doc` which is conditionally included only if it
+comes at the beginning of a line.
+
+#### before_non_blank
+
+`before_non_blank (doc)`
+
+Conditionally includes the given `Doc` unless it is followed by
+a blank space.
+
+#### blankline
+
+`blankline`
+
+Inserts a blank line unless one exists already.
+
+#### blanklines
+
+`blanklines (n)`
+
+Insert blank lines unless they exist already.
+
+Parameters:
+
+`n`
+:   Number of blank lines to insert.
+
+#### braces
+
+`braces (doc)`
+
+Puts a `Doc` in curly braces.
+
+#### brackets
+
+`brackets (doc)`
+
+Puts a `Doc` in square brackets.
+
+#### cblock
+
+`cblock (width, doc)`
+
+Like `lblock` but aligned centered.
+
+Parameters:
+
+`width`
+:   Width of the created block, in characters
+
+`doc`
+:   Contents of the block ([Doc])
+
+#### chomp
+
+`chomp (doc)`
+
+Chomps trailing blank space off of a `Doc`.
+
+#### cr
+
+A carriage return. Does nothing if we're at the beginning of a
+line; otherwise inserts a newline.
+
+#### double_quotes
+
+`double_quotes (doc)`
+
+Wraps a `Doc` in double quotes
+
+#### empty
+
+The empty document.
+
+#### flush
+
+`flush (doc)`
+
+Makes a `Doc` flush against the left margin.
+
+#### hang
+
+`hang (indent, start, doc)`
+
+Creates a hanging indent.
+
+Parameters:
+
+`indent`
+:   Indentation width in characters
+
+`start`
+:   Start, printed unindented
+
+`doc`
+:   Doc which is indented by `indent` spaces on every line.
+
+#### inside
+
+`inside (start, end, contents)`
+
+Encloses a `Doc` inside a start and end `Doc`.
+
+Parameters:
+
+`start`
+:   Doc before contents
+
+`end`
+:   Doc after contents
+
+`contents`
+:   Contents Doc
+
+#### lblock
+
+`lblock (width, doc)`
+
+Creates a block with the given width and content, aligned to the left.
+
+Parameters:
+
+`width`
+:   Width of the created block, in characters
+
+`doc`
+:   Contents of the block ([Doc])
+
+
+#### literal
+
+`literal (string)`
+
+Creates a `Doc` from a string.
+
+#### nest
+
+`nest (indent)`
+
+Indents a `Doc` by the specified number of spaces.
+
+Parameters:
+
+`indent`
+:   Indentation width.
+
+#### nestle
+
+`nestle (doc)`
+
+Removes leading blank lines from a `Doc`.
+
+#### nowrap
+
+`nowrap (doc)`
+
+Makes a `Doc` non-reflowable.
+
+#### parens
+
+`parens (doc)`
+
+Puts a `Doc` in parentheses.
+
+#### prefixed
+
+`prefixed (prefix, doc)`
+
+Uses the specified string as a prefix for every line of the
+inside document (except the first, if not at the beginning of the
+line).
+
+Parameters:
+
+`prefix`
+:   Prefix to prepend to each line
+
+`doc`
+:   Inside Doc.
+
+#### quotes
+
+`quotes (doc)`
+
+Wraps a `Doc` in single quotes.
+
+#### rblock
+
+`rblock (indent, doc)`
+
+Like `lblock` but aligned to the right.
+
+Parameters:
+
+`width`
+:   Width of the created block, in characters
+
+`doc`
+:   Contents of the block ([Doc])
+
+#### space
+
+A breaking (reflowable) space.
+
+#### vfill
+
+`vfill`
+
+Creates an expandable border that, when placed next to a box,
+expands to the height of the box.
+
+Parameters:
+
+`text`
+:   Border text
+
+### Operators
+
+#### `..`
+
+Concatenate two `Doc` elements.
+
+#### `+`
+
+Concatenate two `Doc`s, inserting a reflowable space between them.
+
+#### `/`
+
+If `a` and `b` are `Doc` elements, then `a / b` puts `a` above `b`.
+
+#### `//`
+
+If `a` and `b` are `Doc` elements, then `a // b` puts `a` above
+`b`, inserting a blank line between them.
+
+
+License
+-------
 
 This package is made available under the MIT license. See [`LICENSE`](LICENSE)
 for details.