#Translates RelaxNG to Katydid

Translates Simplified RelaxNG Grammars to the Katydid Relapse Grammar.

There is a playground available here http://katydid.github.io/relaxng/play/

Simplification is defined at these two resources:

• http://debeissat.nicolas.free.fr/relaxng_simplification.php
• http://books.xmlschemata.org/relaxng/relax-CHP-15-SECT-1.html

Usage

simplifiedRelaxNG := `
<grammar>
    <start>
        <ref name="element1"></ref>
    </start>
    <define name="element1">
        <element>
            <name>foo</name>
            <empty></empty>
        </element>
    </define>
</grammar>`
relaxing, _ := ParseGrammar([]byte(simplifiedRelaxNG))
relapse, _ := Translate(relaxing)
input := "<foo/>"
if err := Validate(relapse, []byte(input)); err != nil {
    fmt.Println("invalid")
}
fmt.Println("valid")
// Output: valid

For more see the go package documentation

RelaxNG Test Suite

passed: 146
failed: 0
namespace tests skipped: 13
datatypeLibrary tests skipped: 1
incorrect grammars skipped: 213

Steps:

• The RelaxNG Test Suite is run through the simplifier which also eliminates all the incorrect grammars.
• Next these simplified RelaxNG XML Grammars are parsed and translated to Katydid Relapse.
• Finally the translated Relapse is used to validate the XML.

Viewing all tests can be done in the playground by going to this link, which will load the first test, and then clicking the NextTest button.

Example 1

The Simplified RelaxNG Grammar

<grammar>
    <start>
        <ref name="element1"></ref>
    </start>
    <define name="element1">
        <element>
            <name>foo</name>
            <empty></empty>
        </element>
    </define>
</grammar>

is translated to this Relapse Grammar

@element1
#element1={
    elem_foo:(<empty>|@ws);
    (@ws)*;
}
#ws=->whitespace($string)
#text=->anytext($string)

Example 2

The Simplified RelaxNG Grammar

<grammar>
    <start>
        <ref name="element1"></ref>
    </start>
    <define name="element1">
        <element>
            <name>foo</name>
            <attribute>
                <name>bar</name>
                <text></text>
            </attribute>
        </element>
    </define>
</grammar>

is translated to this Relapse Grammar

@element1
#element1={
    elem_foo:attr_bar:(@text)*;
    (@ws)*;
}
#ws=->whitespace($string)
#text=->anytext($string)

Example 3

The Simplified RelaxNG Grammar

<grammar>
    <start>
        <ref name="element1"></ref>
    </start>
    <define name="element1">
        <element>
            <name>foo</name>
            <choice>
                <group>
                    <attribute>
                        <name>bar</name>
                        <empty></empty>
                    </attribute>
                    <ref name="element2"></ref>
                </group>
                <group>
                    <attribute>
                        <name>bar</name>
                        <text></text>
                    </attribute>
                    <ref name="element3"></ref>
                </group>
            </choice>
        </element>
    </define>
    <define name="element2">
        <element>
            <name>baz1</name>
            <empty></empty>
        </element>
    </define>
    <define name="element3">
        <element>
            <name>baz2</name>
            <empty></empty>
        </element>
    </define>
</grammar>

is translated to this Relapse Grammar

@element1
#element1={
    elem_foo:(
        [
            attr_bar:@ws,
            @element2
        ] |
        [
            attr_bar:(@text)*,
            @element3
        ]
    );
    (@ws)*;
}
#element2={
    elem_baz1:(<empty>|@ws);
    (@ws)*;
}
#element3={
    elem_baz2:(<empty>|@ws);
    (@ws)*;
}
#ws=->whitespace($string)
#text=->anytext($string)

Known Issues

There are quite a few known issues:

• Only simplified grammars are supported.
• namespaces are not supported.
• datatypes: only string and token are currently supported.
• datatypeLibraries are not supported.

I don't really intend to fix these, but you never know.

Only handles simplified relaxng grammars.

http://www.kohsuke.org/relaxng/rng2srng/ seems to be quite effective at converting the full spectrum of what is possible within the relaxng grammar to the simplified grammar.

java -jar rng2srng.jar full.rng > simplified.rng