rsb:enum

The rsb:enum keyword can be used to enumerate through the attributes within an item, the values within a multi-valued attribute, or a supplied range of values. The body of rsb:enum is executed for each element of the set that is being iterated upon.

Parameters:

• item: The name of the item whose attributes you want to iterate upon.
• attr: If present, rsb:enum will only iterate over the attributes matching the specified expression: for example, "rsb:*" You can also provide this parameter to iterate over the values of a multi-valued attribute .
• expand: Boolean parameter that specifies how rsb:enum behaves when multi-valued attributes are encountered. If expand is set to true, the body of rsb:enum> will be executed once for each value of the attribute. If false, all values will be concatenated in a single string value and only a single iteration will be performed for the multiple values. By default rsb:enum will not expand all values..
• separator: If the expand parameter is false, the value of the separator parameter will be used to concatenate values of a multi-valued attribute. The default value is a newline character.
• range: This parameter supports enumerating through a range of numbers or characters in both ascending and descending order: for example, "a..z", "Z..A".
• list: This parameter supports enumerating over a list of separated values. For e.g. if the list of values is "violet, indigo, blue, green, yellow, orange, red" and the separator is a ',' the scope of rsb:enum is executed for each color in the rainbow.

Note that you can specify either the range attribute or the item attribute, but not both.

Control Attributes:

• _attr: This attribute contains the name of the attribute being iterated. When you are iterating over the values of a multi-valued attribute ( attr = "name#"), the attribute name will be the same except that it will also have the index as part of the name: for example, name#1, name#2 etc.
• _index: The _index contains the index at which the attribute appears within an item considering the attributes, sorted alphabetically.
• _value: The _value contains the value of the attribute. For a multi-value attribute, you can see the values distinctly, one in each iteration, or see them all together based on the "expand" and "separator" parameter settings.
• _count: The _count contains the number of values in an attribute.

Examples:

<rsb:set item="input" attr="Greeting" value="Hello" />
<rsb:set item="input" attr="Goodbye" value="See ya" />
<rsb:enum item="input">
    [_attr] is [_value]
    <br/>
</rsb:enum>

This snippet displays the name and values of the item named "input", and generates the following output:

goodbye is See ya greeting is Hello

To enumerate through all the values of an attribute, use the attr argument to specify a multi-value attribute. Such attributes are marked in rsb:info using the item name and ending with the character "#". For example:

<rsb:info desc="..."> 
<output name="email#" desc="Email addresses of the user"/> 
  ... 
</rsb:info>

Assuming that the attribute "email" of the item "foo" has the values joe@rssbus.com and john@rssbus.com, the result of the snippet below would be:

<rsb:set attr="foo.email#1" value="joe@rssbus.com"/>
<rsb:set attr="foo.email#2" value="john@rssbus.com"/>
<rsb:enum attr="foo.email" expand="true">
    ([_index]) [_attr] -> [_value]
</rsb:enum>

(1) email#1 -> joe@rssbus.com (2) email#2 -> john@rssbus.com

Enumerating over a range:

To enumerate over a range of values, use the range attribute. For example:

<rsb:enum range="a..z">
    [_value] 
</rsb:enum>
<rsb:enum range="Z..A">
    [_value] 
</rsb:enum>
<rsb:enum range="1..25">
    [_value] 
</rsb:enum>

The snippets above list the character set from "a" to "z", from "Z" to "A" and the numbers from "1" to "25".

Enumerating over a list of values:

To enumerate over a list of values use the "list" and "separator" parameters of rsb:enum. For example:

<rsb:set attr="colors" value="violet, indigo, blue, green, yellow, orange, red"/>
<rsb:enum list="[colors]" separator=",">
    [_value] 
</rsb:enum>

The snippets above listscolors specified in the colors attribute.

See Also:

• rsb:break: To learn how to break out of rsb:call or rsb:enum iterations
• rsb:continue: To learn how to skip a rsb:call or rsb:enum iteration.
• rsb:first: To learn how to provide special processing in the first iteration.