NewLeaf comes with default settings that allow you to create documents immediately. These settings, however, are not necessarily ideal for everyone. As NewLeaf is supplied in the form of an APL workspace, it is a relatively easy matter to create, modify and delete objects within it, that is, to customise it to suit your own or your users’ requirements. This approach is discouraged, as it may result in unforeseen problems when upgrading to a future version of NewLeaf. While Causeway Graphical Systems will make every reasonable effort to ensure that subsequent releases are upwards compatible functionally, it is impossible to offer similar assurances about the implementation. It is reasonable to expect that the enhancement of existing functionality and the addition of new features will, at some point, necessitate changes to functions and to the structure and content of variables.

In the light of these warnings, this chapter provides information and guidelines for customising NewLeaf. The approach can be summarised as follows:

• Make a backup copy of the NewLeaf workspace and put it somewhere safe.
• Do not alter any of the NewLeaf source code or the structure of any NewLeaf variables. Use existing customising routines where available, rather than altering variables directly.
• Keep the code that customises NewLeaf in a single function if possible. Write an initialisation routine that executes nlInit , then use nlSet or nltSet to change the property values.
• Do not assume that properties persist after nlClose or nlSpool executes to complete a document.
• Always use nlSet and nltSet to set the values of properties, nlQuery and nltQuery to find out their current values.

Make a note of any changes and put it somewhere handy for reference.