Idio Templates

Templates in Idio are like macros in many other Lisp-ish languages. They allow the user to “generate code”.

Their creation and usage is fraught with issues from hygiene, scope, arguments, evaluation (timing, context), … well, you get the picture. It looks easy and obvious but very quickly becomes complicated and possibly intractable.

To help for those less familiar with this sort of thing, consider C pre-processing of a C source file where you’ve defined some complex macros which affect code generation (a bit more complex than #ifdef, say). Pre-processing, whilst part of compilation, is run before the compiler proper gets a look in and uses a different set of variables that, subsequently, the compiler (or you) have no visibility of. You only see the results of the C macro expansion and nothing of the macros or their variables at all.

Templates are much the same in that they are run before the (final) draft of the code is evaluated and use a context (namespace and “thread” of control) separate from regular user contexts except the language of templates is regular Idio and not some special pre-processor language and, to make matters more complicated, you can use any Idio function including those you’ve just defined (including if they were just defined by a template).

• Template Evaluation
• Template Predicates
• Syntax Functions

Last built at 2024-12-21T07:10:43Z+0000 from 62cca4c (dev) for Idio 0.3.b.6