html-writing: Writing HTML from SXML/xexp in Racket

Version: 2:0

html-writing: Writing HTML from SXML/xexp in Racket

Neil Van Dyke

License: LGPLv3 Web: http://www.neilvandyke.org/racket-html-writing/

(require (planet neil/html-writing:2:0))

1 Introduction

Warning: State of flux. Documentation under construction.

The html-writing package provides support for writing HTML encoded as SXML/xexp as HTML.

This can be used for hand-constructed HTML, HTML constructed by program, or emitting HTML that has been read via the html-parsing package.

For a complementary way of writing HTML from SXML/xexp, see the html-template package.

2 Foreign Filters

(current-html-writing-foreign-filter) → !!!
(current-html-writing-foreign-filter ff) → void?
ff : !!!

!!!

3 Writing Procedures

!!! The two most common procedures in html-writing for writing HTML from an SXML/xexp representation are write-html and xexp->html. These are perhaps most useful for emitting the result of parsed and transformed input HTML. They can also be used for emitting HTML from generated or handwritten SXML/xexp.

3.1 Writing Attributes

3.2 Writing Other

3.3 Writing HTML

(write-html xexp out) → void?
xexp : xexp?
out : output-port?

Writes a conventional HTML transliteration of the SXML/xexp xexp to output port out. If out is not specified, the default is the current output port. HTML elements of types that are always empty are written using HTML4-compatible XHTML tag syntax.

!!! If foreign-filter is specified, it is a procedure of two argument that is applied to any non-SXML/xexp (“foreign”) object encountered in xexp, and should yield SXML/xexp. The first argument is the object, and the second argument is a symbol for the context. The possible symbols are: !!!

No inter-tag whitespace or line breaks not explicit in xexp is emitted. The xexp should normally include a newline at the end of the document. For example:

(write-html
'((html (head (title "My Title"))
         (body (@ (bgcolor "white"))
               (h1 "My Heading")
               (p "This is a paragraph.")
               (p "This is another paragraph."))))
(current-output-port))

produces the output:

<html><head><title>My Title</title></head><body bgcolor="white"><h1>My Heading</h1>This is a paragraph.This isanother paragraph.</body></html>

(xexp->html xexp) → string?
xexp : xexp?

Yields an HTML encoding of SXML/xexp xexp as a string. For example:

> (xexp->html
 (html->xexp
 "This is<br<bbold </foo>italic text."))
 "This is bold italic text."

Note that, since this procedure constructs a string, it is normally best used when the HTML is small. When encoding HTML documents of conventional size, write-html is likely more efficient.

4 History

PLaneT 2:0 — 2012-06-12
- Heavy API and implementation changes (although the previous version was not really documented), including the following.
- All out arguments are now mandatory rather than optional.
- All foreign-filter arguments have been removed.
- Foreign filter context value symbol renamed from 'attribute (singular) to 'attributes (plural).
- The suffix /fixed has been removed from all identifiers, since all procedures now have fixed arguments.
- write-html-attribute-or-list is renamed to write-html-attributes.
- write-html-attribute-value-string is renamed to write-html-attribute-value-part-string.
- Added html->bytes and html-attribute-value->bytes.
- We no longer do backward-compatible XHTML empty element terminators like the string " />"; now they’re just ">".
- In attribute values, some additional characters are now written as numeric character references: ASCII 0 through 31, and 127.
- Got rid of the *splice* form that we have experimentally added, and philosophically switched back to SXML’s arbitrarily nested lists for splicing with generally less allocation.
- Restored some of the handling of unnecessary list nesting in SXML/xexp, which had been removed after forking from HtmlPrag and a brief experiment with *splice* when trying to unify SXML and PLT xexprs.
- Converted to McFly and Overeasy.
Version 0.1 — PLaneT 1:0 — 2011-08-21
Part of forked development from HtmlPrag, with substantial changes.

5 Legal

Copyright 2004 – 2012 Neil Van Dyke. This program is Free Software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 3 of the License,or (at your option) any later version. This program is distributed in the hope that it will be useful, but without any warranty; without even the implied warranty of merchantability or fitness for a particular purpose. See http://www.gnu.org/licenses/ for details. For other licenses and consulting, please contact the author.

1	Introduction
2	Foreign Filters
3	Writing Procedures
4	History
5	Legal