re-motion makes good use of program generation
and comes with three command-line program generators:
generates a database schema for persisting domain object instances
generates a ASP.NET-application from domain object classes
generates boilerplate code for re-call page-functions from re-call headers
run-time code generation
transparently sub-classes domain object classes for instantiation
Program generation happens also at run-time. Code for domain object classes is generated for binding and persistence from declared base-classes. What's more, some parts of re-motion organize code in re-mix for better separation of concerns.
Don't confuse these program generators. They corresponding purposes don't overlap. With the exception of run-time code generation, all program generators are command line tools, but
wxegen.exe is not usually invoked by the programmer. (It is invoked by Visual Studio during a build.) The use of each program generator is discussed in the PhoneBook tutorial, and also in this wiki.
An entirely different type of program generation is the creation of so-called "generated types" at run-time. Nothing must be invoked, because this program generation works tacitly in the background and is completely transparent to the programmer.
dbschema.exe is always the first program generator used, because it derives the database schema for persisting domain objects.
dbschema.exe inspects domain object assemblies to find domain object classes, their properties and attributes and generates the database schema – tables and views.
dbschema.exe can be invoked many times in the course of a project, because the programmer does not modify the generated database schema. (This is in contrast to
uigen.exe that can be run only once before making changes. You must start from scratch every time you run
uigen.exe enters the stage as soon as you not only have the properties and attributes for your domain object classes, but also query methods, factory methods and behavior – in short: the "domain". You are ready for the web application.
uigen.exe works like
dbschema.exe in that it inspects the domain object classes, properties and attributes in domain object assemblies
uigen.exe's use is more delicate, however, because it generates the starting point for programming your web application. You customize and extend that web application by modifying the generated files.
uigen.exe is not a round-trip tool. If you change properties (types, constraints) in one or more domain object class, you must
uigen.exe again and start over with your modifications.
dbschema.exe inspect domain object assemblies, but...
uigen.exe is more picky than
dbschema.exe when it comes to usage. Both program generators must load domain object assembly(s) for discovering
domain object classes, but they resort to different libraries for doing so.
uigen.exe(an old program) uses an improvised an fragile mechanism
dbschema.exe(a new program) uses a mature and robust mechanism
In practice, you won't have problems with
dbschema.exe, because it usually does the right thing.
uigen.exe is a robust program that has been in use for years, but that's exactly the problem: it is dated. Don't draw conclusions from
dbschema.exe usage to
uigen.exe usage, and the other way around. How to avoid
uigen.exe assembly discovery failures is explained in detail in using uigen.exe.
wxegen.exe will not be called by you, at least not usually.
wxegen.exe works transparently in the background in Visual Studio.
wxegen.exe parses source code, i.e. it does not inspect assemblies.
wxegen.exe is only interested in so-called "WXE headers" – XML written into comments for pages derived from
EditFormPage represents a web edit form for data entry, but it can be "called" with parameters and has a return value – like a function. Generating the boilerplate for passing parameters and returning a value (if desired) is what
wxegen.exe is designed to do for you.
Whenever you change something in a source file constituting a class derived from
wxegen.exe will run and re-generate the boilerplate. This brief explanation probably remains somewhat mysterious unless you know what re-call is. There is a known problem with
wxegen.exe: it does not work the first time, due to a Visual Studio bug. This is explained here: re-motion mascot bug -- wxegen.exe does not work.
Run-time code generation
re-store is re-motion's persistence layer, i.e. it provides O/R-mapping for domain object classes, as declared by the programmer. Persisting such
objects requires sophisticated machinery that can't be provided by the common baseclass
DomainObject alone. For this reason, mixin technology is used to "mix in" the desired behavior at run-time, before instantiating a given object for the first time. Mixins in general are explained in wikipedia.
You can find an article series about re-motion mixins in the re-motion team-blog and in the exhaustive documentation here: re-mix. The hows and whys of generated types can be found here: generating domain object types at run-time.
Each program generator is discussed in detail in the PhoneBook tutorial. For reference (parameters, errors) use the corresponding wiki-pages:
generating domain object types at run-time