Could Quickstart's code generation system (or a code generation system for crud forms) be written as a set of Kid templates?
Didn't Ian just submit an enhancement to kid that enables text output, which makes kid useful for generating any format of text file? Of course kid templates would need to generate other kid templates. Is there a way of quoting for forcing the namespace, so a kid templates can output xml in the same namespace? One good example of a successful and extremely useful code generation system is SWIG: http://www.swig.org SWIG automatically generates wrappers for C and C++ interfaces, in many different scripting (and general purpose programming) languages. It uses an interface definition language that's an extension of C++ with annotations that let you mark up your interfaces and specify calling conventions, parameters handling, data type conversions, convenience methods, etc. SWIG totally understands C++ data types, even C++ templates, and supports an extensible, pattern based approach to mapping those interfaces to many different scripting languages and extension APIs, including raw xml metadata. SWIG takes an approach to code generation that requires you to declare your extra stuff in an idl file (which looks like a .h file with extra stuff [kinda like those double thick oreos]), so you never have to look at or modify the generated code. The SWIG interface definitions can contain code snippets with variable substitution, which are used for defining convenience methods, general purpose parameters conversions, or scripting-language specific interface adaptors. SWIG is largely written as a bunch of reusable template libraries, a C++ data type pattern based template engine, into which plugs a bunch of back-end code generators for the various languages it supports. (The list of supported languages is quite impressive!) SWIG has a pattern based code generation system, with patterns based on C++ data types and parameter names. It injects dynamically generated code from templates into various places of the interface wrappers. For simple interfaces that you control, you can start with (or include) a normal .h file, and use pattern based type conversion declarations to customize the interface without inserting any annotations, so the C++ compiler can read the same header file as the interface generator, and you Don't Repeat Yourself. But for more complex interfaces (or interfaces you don't control or don't have headers for) you can wrap them by writing your own separate interface definitions in the SWIG superset of C++ syntax, simplify them by omitting unnecessary properties and methods, and extend them by adding helper methods to the wrappers to make more convenient and powerful scripting interfaces. For a great example of how SWIG can wrap a complex set of interfaces, check out the OpenCV open source computer vision library: http://sourceforge.net/projects/opencvlibrary/ http://www.ient.rwth-aachen.de/team/asbach/opencv-python.html There is a big difference between wrapping C++ interfaces and SQL databases, but SWIG has dealt with many thorny code generation issues that are common to both problems, so it's worth taking a good look at. And of course it's actually extremely useful, not just cool to look at! -Don -----Original Message----- From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of william Sent: Friday, November 04, 2005 12:57 PM To: TurboGears Subject: [TurboGears] Re: Interesting thoughts on code generation Michele, thanks, this is a good summary of my ideas. Quickstart should be able to generate a kind of pseudo-code. If re-generation are need, why not take advantage of the inheritance at class level (or at object level like in Zope). But this can add lot of complexity; I like simplicity ;-). Personnally, I'll be very happy even if quickstart does only 80% of the task. If this is well documented where are the 20% to make manually. My dream is to have a Quickstart that build: - standard class controlers with view, edit and save methods. - very simple kid template that just displays data and forms. It's a kind of CatWalk, but at the code level. Concerning the impact of regeneration, I'm just thinking of Glade. They've made something that clearly define (in the generated code) where the developers can add his own code and where he cannot make modifications. William
