Loading Elixir/SQLAlchemy models in .NET? - sqlalchemy

A new requirement has come down from the top: implement 'proprietary business tech' with the awesome, resilient Elixir database I have set up. I've tried a lot of different things, such as creating an implib from the provided interop DLL (which apparently doesn't work like COM dlls) which didn't work at all. CPython doesn't like the MFC stuff either, so all attempts to create a Python lib have failed (using C anyway, not sure you can create a python library from .NET directly).
The only saving grace is the developer saw fit to provide VBA, .NET and MFC Interop C++ hooks into his library, so there are "some" choices, though they all ultimately lead back to the same framework. What would be the best method to:
A) Keep my model definitions in one place, in one language (Python/Elixir/SQLAlchemy)
B) Have this new .NET access the models without resorting to brittle, hard-coded SQL.
Any and all suggestions are welcome.

After a day or so of deliberation, I'm attempting to load the new business module in IronPython. Although I don't really want to introduce to python interpreters into my environment, I think that this will be the glue I need to get this done efficiently.

Related

Is this a job for Yeoman?

I use Yeoman, and I dig it.
However recently I have been wanting more complex code generation tools - now I know I can build custom generators, but I am wondering if people think this is the role/job/whatever that Yeoman is built to play.
Examples are,
Generating a base REST API (in Node) from a JSON schema
Generating MySQL DB Schema from JSON schema etc.
Although I could bend Yeoman to do this - do people think this is a realistic direction?
Is there a better tool for the job?
(Currently I have a bunch of custom Node scripts that suffice).
My humble opinion:
Yeoman is first and foremost a front end tool to create webapps.
Your task seems to be backend related.
You can still use grunt to scaffold your project though.
http://gruntjs.com/project-scaffolding
Cheers

Bestpractice: Annotation-based ORM frameworks like Hibernate for Adobe AIR?

Question
Is there a commonly used framework for AIR that handles mapping objects to and from the built-in SQLite database? An Annotation-based ORM framework that is to AIR what Hibernate is to Java?
Background
We have an AIR application that runs offline. I need to save/restore complex objects to/from the SQLite database. Some of these ValueObjects contain references to other ValueObjects. For example, an Order object contains a Customer object which contains an Address object.
Ultimately, I'd like to add metadata to my objects, like an [Entity] tag and have persistence "just work," with minimal configuration. I could roll my own ORM solution, effectively writing "Hibernate for AIR" myself, but SURELY someone has already done this.
I've read related posts like Best practices for developing AIR Application with SQLite that advocate creating DAO's, Builders and Services. That's a fine solution but, of course, no one wants to reinvent the wheel if it's not 100% necessary.
Candidates
So far, the best I could find is partial solutions. I'll keep a running list here:
SOFA from Matsiya
Technology - seems like it never got off the ground
FlexORM on RIAForge - seems dead, judging by the forum
JazzRecord - is a JavaScript solution that claims to work with Adobe AIR but documentation is sparse
Cairngorm Persistence Library - I hear nothing but bad things about cairngorm & this solution adopts the iBATIS approach, which is not like hibernate
AIR ORM in ColdFusion - not sure if this can be used without coldfusion (if so where do you get cfair.swc)?
Has a framework emerged for this? Specifically, I'm seeking one like Hibernate that uses Annotations/Metatags to map objects to tables. Are one of the candidates above actually acceptable?
What are you using succesfully?
All input is welcome. Thanks!
take a look at FxORM. I worked on a couple of AIR projects with it - it worked fine for quite complex data structure.
Take a look to AS3 SPOd, we use it on a daily basis on a rather large project. No problems so far.

Extending embedded Python in C++ - Design to interact with C++ instances

There are several packages out there that help in automating the task of writing bindings between C\C++ and other languages.
In my case, I'd like to bind Python, some options for such packages are: SWIG, Boost.Python and Robin.
It seems that the straight forward process is to use these packages to create C\C++ linkable libraries (with mostly static functions) and have the higher language be extended using them.
However, my situation is that I already have a developed working system in C++ therefore plan to embed Python into it so that future development will be in Python.
It's not clear to me how, and if at all possible, to use these packages in helping to extend embedded Python in such a way that the Python code would be able to interact with the various Singleton instances already running in the system, and instantiate C++ classes and interact with them.
What I'm looking for is an insight regarding the design best fitted for this situation.
Boost.python lets you do a lot of those things right out of the box, especially if you use smart pointers. You can even inherit from C++ classes in Python, then pass instances of those back to your C++ code and have everything still work. My favorite resource on how to do various stuff is this (especially check out the "How To" section): http://wiki.python.org/moin/boost.python/ .
Boost.python is especially good if you're using smart pointers or intrusive pointers, as those translate transparently into PyObject reference counting. Also, it's very good at making factory functions look like Python constructors, which makes for very clean Python APIs.
If you're not using smart pointers, it's still possible to do all the things you want, but you have to mess with various return and lifetime policies, which can give you a headache.
To make it short: There is the modern alternative pybind11.
Long version: I also had to embed python. The C++ Python interface is small so I decided to use the C Api. That turned out to be a nightmare. Exposing classes lets you write tons of complicated boilerplate code. Boost::Python greatly avoids this by using readable interface definitions. However I found that boost lacks a sophisticated documentation and dor some things you still have to call the Python api. Further their build system seems to give people troubles. I cant tell since i use packages provided by the system. Finally I tried the boost python fork pybind11 and have to say that it is really convenient and fixes some shortcomings of boost like the necessity of the use of the Python Api, ability to use lambdas, the lack of an easy comprehensible documentation and automatic exception translation. Further it is header only and does not pull the huge boost dependency on deployment, so I can definitively recommend it.

Understanding run time code interpretation and execution

I'm creating a game in XNA and was thinking of creating my own scripting language (extremely simple mind you). I know there's better ways to go about this (and that I'm reinventing the wheel), but I want the learning experience more than to be productive and fast.
When confronted with code at run time, from what I understand, the usual approach is to parse into a machine code or byte code or something else that is actually executable and then execute that, right? But, for instance, when Chrome first came out they said their JavaScript engine was fast because it compiles the JavaScript into machine code. This implies other engines weren't compiling into machine code.
I'd prefer not compiling to a lower language, so are there any known modern techniques for parsing and executing code without compiling to low level? Perhaps something like parsing the code into some sort of tree, branching through the tree, and comparing each symbol and calling some function that handles that symbol? (Wild guessing and stabbing in the dark)
I personally wouldn't roll your own parser ( turning the input into tokens ) or lexer ( checking the input tokens for your language grammar ). Take a look at ANTLR for parsing/lexing - it's a great framework and has full source code if you want to dig into the guts of it.
For executing code that you've parsed, I'd look at running a simple virtual machine or even better look at llvm which is an open-source(ish) attempt to standardise the virtual machine byte code format and provide nice features like JITing ( turning your script compiled byte code into assembly ).
I wouldn't discourage you from the more advanced options that you machine such as native machine code execution but bear in mind that this is a very specialist area and gets real complex, real fast!
Earlz pointed out that my reply might seem to imply 'don't bother doing this yourself. Re-reading my post it does sound a bit that way. The reason I mentioned ANTLR and LLVM is they both have heaps of source code and tutorials so I feel this is a good reference source. Take it as a base and play
You can try this framework for building languages (it works well with XNA):
http://www.meta-alternative.net/mbase.html
There are some tutorials:
http://www.meta-alternative.net/calc.pdf
http://www.meta-alternative.net/pfront.pdf
Python is great as a scripting language. I would recommend you make a C# binding for its C API and use that. Embedding Python is easy. Your application can define functions, types/classes and variables inside modules which the Python interpreter can access. The application can also call functions in Python scripts and get a result back. These two features combined gives you a two-way communication scheme.
Basically, you get the Python syntax and semantics for free. What you would need to implement is the API your application exposes to Python. An example could be access to game logic functions and render functions. Python scripts would then define functions which calls these, and the host application would invoke the Python functions (with parameters) to get work done.
EDIT: Seems like IronPython can save you even more work. It's a C# implementation of CPython, and has its own embedding API: http://www.ironpython.net/

Anyone using Lisp for a MySQL-backended web app?

I keep hearing that Lisp is a really productive language, and I'm enjoying SICP. Still, I'm missing something useful that would let me replace PHP for server-side database interaction in web applications.
Is there something like PHP's PDO library for Lisp or Arc or Scheme or one of the dialects?
newLisp has support for mysql5 and if you look at the mysql5 function calls, you'll see that it's close to PDO.
Since nobody has mentioned it, you can try Postmodern, which is an interface to PostgreSQL. It aims for a tighter integration with PostgreSQL and so doesn't pretend to portability between databases.
I've put it together with hunchentoot and cl-who and built a pretty nice website.
newLISP - http://www.newlisp.org/ - has support for MySQL, but I haven't used it (newLISP).
If you're happy with SQL as part of your life, CL-SQL provides a mapping into CLOS objects. It appears to be more mature than Elephant.
I'm using it on my own website.
I've had good success with SBCL and CL-SQL. CL-SQL has a object mapping API, but I used the plain SQL API which simply returns lists and this worked well enough. And in the Clojure language, you interact with JDBC through a maps or structs {:col1 "a", :col2 "b"}, so a generated class library doesn't get you any simpler code, the language handles it nicely. In my experience, there is less cruft between lisp and sql than between more static languages and sql.
our Common Lisp ORM solution is http://common-lisp.net/project/cl-perec/
the underlying SQL lib is http://common-lisp.net/project/cl-rdbms/ (fully tested with PostgreSQL, has a toy SQlite backend and a somewhat tested Oracle backend)
we started out using CLSQL, but after some struggle we decided to roll our own.
these libs and PostgreSQL are used in a clustered web application developed for the Hungarian government for planning the budget of the municipalities. it has about 4000 users, 500 at peek time. a little more info is available at http://common-lisp.net/project/cl-dwim/
Cliki is a good resource for Common Lisp libraries:
http://www.cliki.net/database
There is a project named Elephant (http://common-lisp.net/project/elephant/index.html), which is an abstraction for object persistence in CL.
As long as you're switching your Webapp on Lisp, consider using persistence: you now have a constantly running Lisp image that holds everything about your application. I personnally used Elephant for that.
Elephant can use CL-SQL or BDB as it's backend, which means that you can use MySQL if you have one running. I found using SQLite really practical, though.
We use SBCL, UCW, CL-SQL and MySQL as our back-end for Paragent.com. It has worked very well for us. We also have a number of clients using UCW/CL-SQL/MySQL for custom sites we have built them through our consulting arm Bitfauna.