Variables

Template variables provide a convenient way of storing and retrieving data within a template. This section explains how variables are defined and referenced.

Variable Definitions

Variable definitions take the basic form:

$<name> = <value>

where <name> can be any alpha-numeric sequence and <value> is derived from a macro or another variable.

A simple example definition would be:

$foo = %className%

Variables can be defined using values from:

Substitution, function or list macros
String literals, enclosed within double quotation marks
Variable references

Definition Rules

These rules apply to variable definitions:

Variables have global scope within the template in which they are defined and are not accessible to other templates
Each variable must be defined at the start of a line, without any intervening white space
Variables are denoted by prefixing the name with $, as in $foo
Variables do not have to be declared, prior to being defined
Variables must be defined using either the assignment operator (=), or the addition-assignment operator (+=)
Multiple terms can be combined in a single definition using the addition operator (+)

Examples

Using a substitution macro:

$foo = %opTag:"bar"%

Using a literal string:

$foo = "bar"

Using another variable:

$foo = $bar

Using a list macro:

$ops = %list="Operation" @separator="\n\n" @indent="\t"%

Using the addition-assignment operator (+=):

$body += %list="Operation" @separator="\n\n" @indent="\t"%

That definition is equivalent to:

$body = $body + %list="Operation" @separator="\n\n" @indent="\t"%

Using multiple terms:

$templateArgs = %list="ClassParameter" @separator=", "%

$template ="template<" + $templateArgs + ">"

Variable References

Variable values can be retrieved by using a reference of the form:

$<name>

where <name> can be a previously defined variable.

Variable references can be used:

As part of a macro, such as the argument to a function macro
As a term in a variable definition
As a direct substitution of the variable value into the output

It is legal to reference a variable before it is defined. In this case, the variable is assumed to contain an empty string value: ""

Variable References - Example 1

Using variables as part of a macro. This is an excerpt from the default C++ ClassNotes template.

$wrapLen = %genOptWrapComment%

$style = %genOptCPPCommentStyle% (Define variables to store the style and wrap length options)

%if $style == "XML.NET"% (Reference to $style as part of a condition)

%XML_COMMENT($wrapLen)%

%else%

%CSTYLE_COMMENT($wrapLen)% (Reference to $wrapLen as an argument to function macro)

%endIf%

Variable References - Example 2

Using variable references as part of a variable definition.

$foo = "foo" (Define our variables)

$bar = "bar"

$foobar = $foo + $bar ($foobar now contains the value foobar)

Variable References - Example 3

Substituting variable values into the output.

$bases=%classInherits% (Store the result of the ClassInherits template in $bases)

Class %className%$bases (Now output the value of $bases after the Class name)