Introduction

ISML expressions encode arithmetical, Boolean, and string operations, as well as special function calls. They are used to perform calculations, to compare values, or to produce new values in combination with functions. ISML expressions are evaluated at runtime every time output is generated from a specific template.

Expressions can be composed of:

• Template Variables
  See Reference - ISML Template Variables for details.
• Constants
  See Reference - ISML Constants for details.
• Operators
  See Reference - ISML Operators for details.
• ISML functions
  See Reference - ISML Functions for details.

Expression Example

A sample ISML expression looks as follows:

#len(sub:DisplayName)>15#

It consists of a function (len(), a template variable sub:DisplayName, and an operator >.
An expression always evaluates to a value of a specific data type as shown in the table below:

Expression Conventions

Please note the following hints regarding ISML expressions:

• ISML expressions must be surrounded with pound signs (#).

  Example

  =#len(sub:DisplayName) > 15#
  

• Do not use expressions outside of tags, in order to be sure that the expressions are properly parsed by HTML editors during the design phase.

• This is the universal syntactic description of an ISML expression:

  Syntax

  ISML expression := # <operation> #
  

• You can use different elements to build ISML expressions, see Expressions Syntaxfor details.

Expression Syntax

The following table lists the different elements that can be used to build ISML expressions.

ISML Formatting Expression Results

If the result of an expression is printed out to an HTML page, it is often useful if you can specify how this should be done. For example, a date can be formatted in different ways depending on the store's locale:

• 12 March 1999
• 12.03.1999
• 03/12/99

For formatting values of the data types Money, Number, Quantity, Date, and Message, Intershop 7 uses specific standard formatter classes. The table below lists the data types and their appropriate formatter class.

General

Please mind the following general notes regarding formatters:

• All formatters are additionally customized by regional settings.
• Objects of classes other than Money, Date, Message, Quantity and Number will not be formatted and the result of formatting these objects is not standardized.
• The EURO-styles are a temporary work-around for the direct support of multicurrency pages.

A standard formatter class needs a special formatter string. There are three ways to provide such a string:

• Specifying one of the formatter strings pre-defined by a formatter class (they are called styles).
• Using the default style of a formatter class.
• Providing a user-defined formatter string.

Using Styles

Styles are pre-defined formatter strings, which are defined in standard formatter classes. You can specify a style via the style attribute of <ISPRINT>, or in combination with getValue().

StaticMoneyFormat

This class is used to format expression results of type Money. See the table below for valid styles. As shown in the table, the style identifier is capable of converting between the Euro currency and a predecessor currency, the Deutsche Mark, at the fixed rate of 1 Euro to 1.95583 Deutsche Mark.

DecimalFormat

This class is used to format expression results of type Number. See the table below for valid styles.

StaticQuantityFormat

This class is used to format expression results of type Quantity. See the table below for valid styles.

SimpleDateFormat

This class is used to format expression results of type Date. See the table below for valid styles.

The styles listed in the following table are available for date/time input fields.

MessageFormat

This class is used to format expression results of type Message. The formatter of this class cannot be customized. It has a standard behavior. For more information, see the Java documentation in <IS.INSTANCE.SHARE>/docs.

Using the Default Style of a Formatter Class

The default style of a formatter class is used if nothing else has been specified by the user, neither a style, nor a user-defined formatter style. See the table below for a list of default styles.

Specifying User-defined Formatter Strings

A formatter string is explicitly given by the user via the formatter attribute of <ISPRINT> or in combination with getValue(). For more information about valid placeholders, see the Java documentation in <IS.INSTANCE.SHARE>/ docs. See the table below for examples of user-defined formatter strings.

Encoding Expression Results

It is possible to use national characters, such as Greek or Cyrillic letters, as well as mathematical symbols and any non-ASCII characters in HTML documents. To ensure that a web browser can interpret and display these characters correctly, they need to be encoded using HTML representations. In order to do this, you need to replace characters, such as "<", ">", or "&" with named character entities as defined in the HTML 4.01 standard. Because the result of an expression can be a string that might contain a special character expression, results are automatically encoded if you use <ISPRINT> to output them. See the example below, which shows the exact string returned by <ISPRINT> for a string containing a quote sign. The example assumes that the template variable product:name stores the value Nokia 447X Pro 17" Monitor.

The following ISML code in a template:

<ISPRINT value="#Product:Name#">

generates this HTML code:

"Nokia 447X Pro 17" Monitor"

which is displayed by the browser as:

Nokia 447X Pro 17" Monitor

Expressions outside <ISPRINT>are never automatically encoded. In this case, if you need to encode characters, you have to use the stringToHtml() function.