Attributes and values

Many DTL start tags contain attributes and values that define various physical and operating characteristics of the dialog elements. While most attributes and values are optional, or contain default settings, some are required.

For example, the PANEL tag has a required NAME attribute that must be specified to identify the panel. The value you assign to the NAME attribute must be unique for each panel in a source file. This PANEL tag has the NAME value "panel1":

<panel name=panel1>
</panel>

The PANEL tag also has two optional attributes, DEPTH and WIDTH, whose values specify the dimensions of the panel. For these types of attributes, you specify a numeric value.

<panel name=panel1 depth=20 width=40>
</panel>

Values for some of the tag attributes are predetermined; that is, you can choose from one of a number of keyword values for the tag. For example, the FIG (figure) tag has a FRAME attribute that specifies the top and bottom borders of the figure. The value you assign to the FRAME attribute can be either RULE, which produces a visible border above and below the figure, or NONE, which results in a figure without a border. No other value is acceptable for the FRAME attribute.

RULE is the default value, which means that the figure formats with visible borders if you do not specify the FRAME attribute.

The markup for a figure without ruled borders looks like this:

<fig frame=none>
</fig>

When coding attribute values you must use single or double quotes to enclose values that contain characters other than A-Z, a-z, 0-9, a hyphen (-), or a period (.).

For example, the value assigned to the TYPE attribute of this VARCLASS tag contains a blank, so the value must be enclosed in quotes:

<varclass name=boolean type='char 1'>

Some attributes can be assigned either a specific value, such as a number or a character string, or a variable name. To distinguish a variable name from a specific value, precede the variable name with a percent (%) sign. This convention is called % notation. The percent sign distinguishes the variable name from a specific value. To specify a string that begins with a %, you must code an additional % before the string to distinguish it from a variable name. (For example, to specify the string "%abc", code "%%abc").

Here is an example where the ACTION attribute uses % notation to specify a variable named "varname":

<cmdact action='%varname'>

The length of any attribute value is limited to 253 characters, unless stated otherwise. This includes the lengths of any entity references that are a part of the value.

Generally, you can code tags, attributes, and values in uppercase, lowercase, or mixed case; the results are always the same regardless of case. The conventions you must follow for case-sensitive processing for each tag are described in Tag reference.