The non-terminal html//1 translates a specification into a list of
atoms and layout instructions. Currently the layout instructions are
terms of the format nl(N), requesting at least N
newlines. Multiple consecutive nl(1) terms are combined to
an atom containing the maximum of the requested number of newline
characters.
To simplify handing the data to a client or storing it into a file,
the following predicates are available from this library:
- reply_html_page(:Head,
:Body)
- Same as
reply_html_page(default, Head, Body).
- reply_html_page(+Style,
:Head, :Body)
- Writes an HTML page preceded by an HTTP header as required by
library(http_wrapper)
(CGI-style). Here is a simple typical example:
reply(Request) :-
reply_html_page(title('Welcome'),
[ h1('Welcome'),
p('Welcome to our ...')
]).
The header and footer of the page can be hooked using the
grammar-rules user:head//2 and user:body//2. The first argument passed
to these hooks is the Style argument of reply_html_page/3
and the second is the 2nd (for head//2) or 3rd (for body//2) argument of reply_html_page/3.
These hooks can be used to restyle the page, typically by embedding the
real body content in a div. E.g., the following code
provides a menu on top of each page of that is identified using the
style
myapp.
:- multifile
user:body//2.
user:body(myapp, Body) -->
html(body([ div(id(top), \application_menu),
div(id(content), Body)
])).
Redefining the head can be used to pull in scripts, but
typically html_requires//1 provides a more modular approach for pulling
scripts and CSS-files.
- reply_html_partial(+HTML)
- Reply with partial HTML document. The reply only contains the element
from HTML, i.e., this predicate does not add a
DOCTYPE
header,
html, head or body. It is
intended for JavaScript handlers that request a partial document and
insert that somewhere into the existing page DOM. See reply_html_page/3
to reply with a complete (valid) HTML page.
- print_html(+List)
- Print the token list to the Prolog current output stream.
- print_html(+Stream,
+List)
- Print the token list to the specified output stream
- html_print_length(+List,
-Length)
- When calling html_print/[1,2]
on List, Length characters will be produced.
Knowing the length is needed to provide the
Content-length
field of an HTTP reply-header.
