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.TH "XMLWF" "1" "22 April 2002" "" ""

.SH NAME

xmlwf \- Determines if an XML document is well-formed

.SH SYNOPSIS

\fBxmlwf\fR [ \fB-s\fR]  [ \fB-n\fR]  [ \fB-p\fR]  [ \fB-x\fR]  [ \fB-e \fIencoding\fB\fR]  [ \fB-w\fR]  [ \fB-d \fIoutput-dir\fB\fR]  [ \fB-c\fR]  [ \fB-m\fR]  [ \fB-r\fR]  [ \fB-t\fR]  [ \fB-v\fR]  [ \fBfile ...\fR] 

.SH "DESCRIPTION"

.PP

\fBxmlwf\fR uses the Expat library to determine

if an XML document is well-formed.  It is non-validating.

.PP

If you do not specify any files on the command-line,

and you have a recent version of xmlwf, the input

file will be read from stdin.

.SH "WELL-FORMED DOCUMENTS"

.PP

A well-formed document must adhere to the

following rules:

.TP 0.2i

\(bu

The file begins with an XML declaration.  For instance,

<?xml version="1.0" standalone="yes"?>.

\fBNOTE:\fR xmlwf does not currently

check for a valid XML declaration.

.TP 0.2i

\(bu

Every start tag is either empty (<tag/>)

or has a corresponding end tag.

.TP 0.2i

\(bu

There is exactly one root element.  This element must contain

all other elements in the document.  Only comments, white

space, and processing instructions may come after the close

of the root element.

.TP 0.2i

\(bu

All elements nest properly.

.TP 0.2i

\(bu

All attribute values are enclosed in quotes (either single

or double).

.PP

If the document has a DTD, and it strictly complies with that

DTD, then the document is also considered \fBvalid\fR.

xmlwf is a non-validating parser -- it does not check the DTD.

However, it does support external entities (see the -x option).

.SH "OPTIONS"

.PP

When an option includes an argument, you may specify the argument either

separate ("d output") or mashed ("-doutput").  xmlwf supports both.

.TP

\fB-c\fR

If the input file is well-formed and xmlwf doesn't

encounter any errors, the input file is simply copied to

the output directory unchanged.

This implies no namespaces (turns off -n) and

requires -d to specify an output file.

.TP

\fB-d output-dir\fR

Specifies a directory to contain transformed

representations of the input files.

By default, -d outputs a canonical representation

(described below).

You can select different output formats using -c and -m.

The output filenames will

be exactly the same as the input filenames or "STDIN" if the input is

coming from STDIN.  Therefore, you must be careful that the

output file does not go into the same directory as the input

file.  Otherwise, xmlwf will delete the input file before

it generates the output file (just like running

cat < file > file in most shells).

Two structurally equivalent XML documents have a byte-for-byte

identical canonical XML representation.

Note that ignorable white space is considered significant and

is treated equivalently to data.

More on canonical XML can be found at

http://www.jclark.com/xml/canonxml.html .

.TP

\fB-e encoding\fR

Specifies the character encoding for the document, overriding

any document encoding declaration.  xmlwf

has four built-in encodings: 

US-ASCII,

UTF-8,

UTF-16, and

ISO-8859-1.

Also see the -w option.

.TP

\fB-m\fR

Outputs some strange sort of XML file that completely

describes the the input file, including character postitions.

Requires -d to specify an output file.

.TP

\fB-n\fR

Turns on namespace processing.  (describe namespaces)

-c disables namespaces.

.TP

\fB-p\fR

Tells xmlwf to process external DTDs and parameter

entities.

Normally xmlwf never parses parameter entities.

-p tells it to always parse them.

-p implies -x.

.TP

\fB-r\fR

Normally xmlwf memory-maps the XML file before parsing.

-r turns off memory-mapping and uses normal file IO calls instead.

Of course, memory-mapping is automatically turned off

when reading from STDIN.

.TP

\fB-s\fR

Prints an error if the document is not standalone. 

A document is standalone if it has no external subset and no

references to parameter entities.

.TP

\fB-t\fR

Turns on timings.  This tells Expat to parse the entire file,

but not perform any processing.

This gives a fairly accurate idea of the raw speed of Expat itself

without client overhead.

-t turns off most of the output options (-d, -m -c, ...).

.TP

\fB-v\fR

Prints the version of the Expat library being used, and then exits.

.TP

\fB-w\fR

Enables Windows code pages.

Normally, xmlwf will throw an error if it runs across

an encoding that it is not equipped to handle itself.  With

-w, xmlwf will try to use a Windows code page.  See

also -e.

.TP

\fB-x\fR

Turns on parsing external entities.

Non-validating parsers are not required to resolve external

entities, or even expand entities at all.

Expat always expands internal entities (?),

but external entity parsing must be enabled explicitly.

External entities are simply entities that obtain their

data from outside the XML file currently being parsed.

This is an example of an internal entity:

.nf

<!ENTITY vers '1.0.2'>

.fi

And here are some examples of external entities:

.nf

<!ENTITY header SYSTEM "header-&vers;.xml">  (parsed)

<!ENTITY logo SYSTEM "logo.png" PNG>         (unparsed)

.fi

.TP

\fB--\fR

For some reason, xmlwf specifically ignores "--"

anywhere it appears on the command line.

.PP

Older versions of xmlwf do not support reading from STDIN.

.SH "OUTPUT"

.PP

If an input file is not well-formed, xmlwf outputs

a single line describing the problem to STDOUT.

If a file is well formed, xmlwf outputs nothing.

Note that the result code is \fBnot\fR set.

.SH "BUGS"

.PP

According to the W3C standard, an XML file without a

declaration at the beginning is not considered well-formed.

However, xmlwf allows this to pass.

.PP

xmlwf returns a 0 - noerr result, even if the file is

not well-formed.  There is no good way for a program to use

xmlwf to quickly check a file -- it must parse xmlwf's STDOUT.

.PP

The errors should go to STDERR, not stdout.

.PP

There should be a way to get -d to send its output to STDOUT

rather than forcing the user to send it to a file.

.PP

I have no idea why anyone would want to use the -d, -c

and -m options.  If someone could explain it to me, I'd

like to add this information to this manpage.

.SH "ALTERNATIVES"

.PP

Here are some XML validators on the web:

.nf

http://www.hcrc.ed.ac.uk/~richard/xml-check.html

http://www.stg.brown.edu/service/xmlvalid/

http://www.scripting.com/frontier5/xml/code/xmlValidator.html

http://www.xml.com/pub/a/tools/ruwf/check.html