|
|
|
|
|
// the YML homepage
|
|
|
|
|
|
|
|
|
|
|
|
include homepage.en.yhtml2
|
|
|
|
|
|
|
|
|
|
|
|
page "YML – Why a Markup Language?!" {
|
|
|
|
|
|
h1 > Introduction
|
|
|
|
|
|
|
|
|
|
|
|
h2 > What is YML?
|
|
|
|
|
|
|
|
|
|
|
|
p >>
|
|
|
|
|
|
Well, it's the idea not to need to define a grammar first when you want to use a
|
|
|
|
|
|
¬http://en.wikipedia.org/wiki/Domain_Specific_Language Domain Specific Language¬.
|
|
|
|
|
|
For that purpose, YML is being translated into XML. Let's make an example.
|
|
|
|
|
|
>>
|
|
|
|
|
|
|
|
|
|
|
|
p >>
|
|
|
|
|
|
Everything which comes close to a C like language, parses without a grammar
|
|
|
|
|
|
definition:
|
|
|
|
|
|
>>
|
|
|
|
|
|
|
|
|
|
|
|
p > This:
|
|
|
|
|
|
|
|
|
|
|
|
Code
|
|
|
|
|
|
||
|
|
|
|
|
|
template< class T > T max(T a, T b);
|
|
|
|
|
|
||
|
|
|
|
|
|
|
|
|
|
|
|
p > Parses to:
|
|
|
|
|
|
|
|
|
|
|
|
Code
|
|
|
|
|
|
||
|
|
|
|
|
|
<?xml version='1.0' encoding='UTF-8'?>
|
|
|
|
|
|
<template>
|
|
|
|
|
|
<generic>
|
|
|
|
|
|
<class/>
|
|
|
|
|
|
<T/>
|
|
|
|
|
|
</generic>
|
|
|
|
|
|
<T>
|
|
|
|
|
|
<max>
|
|
|
|
|
|
<parm>
|
|
|
|
|
|
<T/>
|
|
|
|
|
|
<a/>
|
|
|
|
|
|
</parm>
|
|
|
|
|
|
<parm>
|
|
|
|
|
|
<T/>
|
|
|
|
|
|
<b/>
|
|
|
|
|
|
</parm>
|
|
|
|
|
|
</max>
|
|
|
|
|
|
</T>
|
|
|
|
|
|
</template>
|
|
|
|
|
|
||
|
|
|
|
|
|
|
|
|
|
|
|
p >>
|
|
|
|
|
|
Instead of defining grammars, you test out and play around until the
|
|
|
|
|
|
results are matching your needs. If the resulting tree does not fit
|
|
|
|
|
|
what you're expecting, change it by patching the grammar with `code > decl`:
|
|
|
|
|
|
>>
|
|
|
|
|
|
|
|
|
|
|
|
p > This:
|
|
|
|
|
|
|
|
|
|
|
|
Code
|
|
|
|
|
|
||
|
|
|
|
|
|
module A {
|
|
|
|
|
|
interface B {
|
|
|
|
|
|
attribute long n;
|
|
|
|
|
|
};
|
|
|
|
|
|
};
|
|
|
|
|
|
||
|
|
|
|
|
|
|
|
|
|
|
|
p > Parses to:
|
|
|
|
|
|
|
|
|
|
|
|
Code
|
|
|
|
|
|
||
|
|
|
|
|
|
<?xml version='1.0' encoding='UTF-8'?>
|
|
|
|
|
|
<module>
|
|
|
|
|
|
<A>
|
|
|
|
|
|
<interface>
|
|
|
|
|
|
<B>
|
|
|
|
|
|
<attribute>
|
|
|
|
|
|
<long>
|
|
|
|
|
|
<n/>
|
|
|
|
|
|
</long>
|
|
|
|
|
|
</attribute>
|
|
|
|
|
|
</B>
|
|
|
|
|
|
</interface>
|
|
|
|
|
|
</A>
|
|
|
|
|
|
</module>
|
|
|
|
|
|
||
|
|
|
|
|
|
|
|
|
|
|
|
p >>
|
|
|
|
|
|
This does not look like what we want. So we tell YML that
|
|
|
|
|
|
we have a module name after the module, an interface name after
|
|
|
|
|
|
the interface and type and name after the attribute:
|
|
|
|
|
|
>>
|
|
|
|
|
|
|
|
|
|
|
|
p > This:
|
|
|
|
|
|
|
|
|
|
|
|
Code
|
|
|
|
|
|
||
|
|
|
|
|
|
decl module @name;
|
|
|
|
|
|
decl interface @name;
|
|
|
|
|
|
decl attribute @type @name;
|
|
|
|
|
|
|
|
|
|
|
|
module A {
|
|
|
|
|
|
interface B {
|
|
|
|
|
|
attribute long n;
|
|
|
|
|
|
};
|
|
|
|
|
|
};
|
|
|
|
|
|
||
|
|
|
|
|
|
|
|
|
|
|
|
p > Parses to:
|
|
|
|
|
|
|
|
|
|
|
|
Code
|
|
|
|
|
|
||
|
|
|
|
|
|
<?xml version='1.0' encoding='UTF-8'?>
|
|
|
|
|
|
<module name="A">
|
|
|
|
|
|
<interface name="B">
|
|
|
|
|
|
<attribute type="long" name="n"/>
|
|
|
|
|
|
</interface>
|
|
|
|
|
|
</module>
|
|
|
|
|
|
||
|
|
|
|
|
|
|
|
|
|
|
|
h2 id=what > What can I do with YML?
|
|
|
|
|
|
|
|
|
|
|
|
p > With YML you can:
|
|
|
|
|
|
|
|
|
|
|
|
ul {
|
|
|
|
|
|
li p > use a C-like ¬http://en.wikipedia.org/wiki/Domain-specific_language DSL¬ without writing a grammar first
|
|
|
|
|
|
li p > generate code out of this ¬http://en.wikipedia.org/wiki/Domain-specific_language DSL¬ using ¬yslt YSLT¬
|
|
|
|
|
|
li p > generate code out of ¬http://en.wikipedia.org/wiki/Unified_Modeling_Language UML¬ using ¬yslt YSLT¬ on ¬http://en.wikipedia.org/wiki/XML_Metadata_Interchange XMI¬
|
|
|
|
|
|
li p > generate code out of any XML based language like ¬http://en.wikipedia.org/wiki/Scalable_Vector_Graphics SVG¬ using ¬yslt YSLT¬
|
|
|
|
|
|
li p > define a ¬http://en.wikipedia.org/wiki/Wiki wiki¬ like language in just a few lines like ¬http://fdik.org/yml/programming#wiki YHTML¬ does
|
|
|
|
|
|
li p > replace bad designed and complicated XML languages with simpler C-like ones
|
|
|
|
|
|
li p > ... and much more.
|
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
h2 id=howitworks > How it works: Replacing angle brackets with some Python
|
|
|
|
|
|
|
|
|
|
|
|
p > Just writing down what I wanted to have instead of XML for a sample:
|
|
|
|
|
|
|
|
|
|
|
|
Code ||
|
|
|
|
|
|
<list name="List of goods">
|
|
|
|
|
|
<head>
|
|
|
|
|
|
<columTitle>
|
|
|
|
|
|
Goods
|
|
|
|
|
|
</columnTitle>
|
|
|
|
|
|
<columnTitle>
|
|
|
|
|
|
Price
|
|
|
|
|
|
</columnTitle>
|
|
|
|
|
|
</head>
|
|
|
|
|
|
<row>
|
|
|
|
|
|
<value>
|
|
|
|
|
|
Beer
|
|
|
|
|
|
</value>
|
|
|
|
|
|
<value>
|
|
|
|
|
|
20
|
|
|
|
|
|
</value>
|
|
|
|
|
|
</row>
|
|
|
|
|
|
<row>
|
|
|
|
|
|
<value>
|
|
|
|
|
|
Wine
|
|
|
|
|
|
</value>
|
|
|
|
|
|
<value>
|
|
|
|
|
|
30
|
|
|
|
|
|
</value>
|
|
|
|
|
|
</row>
|
|
|
|
|
|
</list>
|
|
|
|
|
|
||
|
|
|
|
|
|
|
|
|
|
|
|
p > Something like that should be more easy, say, like this:
|
|
|
|
|
|
|
|
|
|
|
|
Code ||
|
|
|
|
|
|
list "List of goods" {
|
|
|
|
|
|
head title "Goods", title "Price";
|
|
|
|
|
|
row value "Beer", value 20;
|
|
|
|
|
|
row value "Wine", value 30;
|
|
|
|
|
|
}
|
|
|
|
|
|
||
|
|
|
|
|
|
|
|
|
|
|
|
h2 id=ylanguages > Y Languages
|
|
|
|
|
|
|
|
|
|
|
|
p >>
|
|
|
|
|
|
The latter is what I call an Y language – a language specified in YML. How could this be
|
|
|
|
|
|
achieved? Well, what's to do? To have the required information, how to build XML from the
|
|
|
|
|
|
script above, we need:
|
|
|
|
|
|
>>
|
|
|
|
|
|
|
|
|
|
|
|
ul {
|
|
|
|
|
|
li >>
|
|
|
|
|
|
the information, that “list of goods” is an attribute named «name», while «Goods» is
|
|
|
|
|
|
the text value of a tag
|
|
|
|
|
|
>>
|
|
|
|
|
|
li > «title» shout be written out as «columnTitle»
|
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
p > How to do that? Let's invent a simple definition language for that information:
|
|
|
|
|
|
|
|
|
|
|
|
Code ||
|
|
|
|
|
|
decl list(name);
|
|
|
|
|
|
decl title alias columnTitle;
|
|
|
|
|
|
||
|
|
|
|
|
|
|
|
|
|
|
|
p > Here you can ¬samples/list.yml2 download the complete list sample¬.
|
|
|
|
|
|
|
|
|
|
|
|
div id=bottom > ¬#top ^Top^¬ ¬programming >> Using YML 2¬ ¬index.en.yhtml2 (source)¬
|
|
|
|
|
|
}
|
