Please note : This help page is not for the latest version of Enterprise Architect. The latest help can be found here.

Prev Next

The Processing Instruction (PI) Macro

The PI (Processing Instruction) macro provides a means of defining the separator text to be inserted between the code pieces (which represent entities) that are generated using a template.

The structure for setting the Processing Instruction is:


In this structure, <value> is a literal string enclosed by double quotes, with these options:

  • "\n" - New line (the default)
  • " " - Space
  • "\t" - Tab
  • "" - Null

By default, the PI is set to generate a new line (\n) for each non-empty substitution, which behavior can be changed by resetting the PI macro. For instance, a Class’s Attribute declaration in simple VB code would be generated to a single line statement (with no new lines). These properties are derived from the Class-Attribute Properties in the model to generate, for example:

     Private Const PrintFormat As String = "Portrait"

The template for generating this starts with the PI being set to a space rather than a new line:

     % PI = " " %

     % CONVERT_SCOPE (attScope)%

     % endIf %

     % if attConst == "T" %


     % endIf %

On transforming this, attscope returns the VB keyword 'Private' and attConst returns 'Const' on the same line spaced by a single space (fitting the earlier VB Class.Attribute definition example).

Alternatively, when generating a Class you might want the Class declaration, the notes and Class body all separated by double lines. In this case the %PI is set to '/n/n' to return double line spacing:

     % PI = "\n\n" %

     % ClassDeclaration %

     % ClassNotes %

     % ClassBody %

PI Characteristics

  • Blank lines have no effect on the output
  • Any line that has a macro that produces an empty result does not result in a PI separator (space/new line)
  • The last entry does not return a PI; for example, %Classbody% (above) does not have a double line added after the body

Learn more