Relax NG Projects
Catalog

Project Index | Documentation | Relax NG | Sample XML File

• A <catalog> consists of a <company> element followed by one or more <department> elements.

• A <company> element contains plain text.

• A <department> contains one or more <item> elements. It must have a name attribute and a unique code attribute.

• An <item> element contains <name> followed by, in any order, a <price>, an optional <manufacturer>, a color specification (see below), a <summary>, and an optional <description>

• The <name> and <manufacturer> elements contain plain text. The <summary> and <description> may contain a small subset of HTML, as described below.

• The <price> is an empty element which has a required amt attribute that specifies the price as a decimal number, and it must be in the form of a decimal number. It also has an optional units attribute, which may have a value of either USD or CDN.

• A color specification is either a single <color> element (for those items that come in only one color), or a <color-list> (for items that come in multiple colors), or an <sku> element (for items that have no color). These are further defined as:

  • A <color> element contains text, and has a required sku attribute and an optional hex attribute. The sku attribute must begin with one or two capital letters followed by 3 or 4 digits, and (optionally) a hyphen and two alphabetic characters. The hex attribute must be in the form of a # followed by six hexadecimal digits, upper or lowercase.

  • The <color-list> element contains one or more <color> elements.

  • An <sku> element contains text which must begin with one or two capital letters followed by 3 or 4 digits, and (optionally) a hyphen and two alphabetic characters.

We define a color specification as either a single <color> element (for those items that come in only one color), or a <color-list> (for items that come in multiple colors), or an <sku> element (for items that have no color).

The reason that we have this strange setup for colors, color-lists, and SKUs is that every item in the catalog must have an SKU (which stands for Stock Keeping Unit, and is an inventory code). Here are the cases that these elements cover:

1. An item doesn't have a color (e.g., "Diet Soda 12-pack") In that case, it needs an <sku> element to keep track of inventory.

2. An item comes in only one color (e.g., a whiteboard). It will have one <color> element, and that element has a required sku attribute to keep track of the inventory for that item. The hex attribute is optional, and is used only if its color happens to be representable as a color code like you find in HTML (#ffca03, etc.)

3. An item comes in many colors (for example, ballpoint pens). You now need a <color-list> which has individual <color> elements. Each of them has a different sku attribute, so that we can keep track of how many blue pens we've sold vs. black pens vs. red pens. Each one also has an optional hex attribute in case its color happens to be representable as an HTML color code.

HTML Subset

The <summary> and <description> elements may contain a subset of HTML as follows:

First, we define inline elements as the <em> and <strong> elements, which may contain text and other inline elements. Given that definition, the <summary> and <description> elements may contain:

• Text with inline elements

• The <p> (paragraph) element, which may contain text with inline elements.

• The <ul> element, which contains <li> elements.

• Each <li> element may contain text with inline elements and <p> (paragraphs).

• You may nest <ul> elements within an <li>.