Simplfying DSL written for a C# app with IronPython - c#

Thanks to suggestions from a previous question, I'm busy trying out IronPython, IronRuby and Boo to create a DSL for my C# app. Step one is IronPython, due to the larger user and knowledge base. If I can get something to work well here, I can just stop.
Here is my problem:
I want my IronPython script to have access to the functions in a class called Lib. Right now I can add the assembly to the IronPython runtime and import the class by executing the statement in the scope I created:
// load 'ScriptLib' assembly
Assembly libraryAssembly = Assembly.LoadFile(libraryPath);
_runtime.LoadAssembly(libraryAssembly);
// import 'Lib' class from 'ScriptLib'
ScriptSource imports = _engine.CreateScriptSourceFromString("from ScriptLib import Lib", SourceCodeKind.Statements);
imports.Execute(_scope);
// run .py script:
ScriptSource script = _engine.CreateScriptSourceFromFile(scriptPath);
script.Execute(_scope);
If I want to run Lib::PrintHello, which is just a hello world style statement, my Python script contains:
Lib.PrintHello()
or (if it's not static):
library = new Lib()
library.PrintHello()
How can I change my environment so that I can just have basic statments in the Python script like this:
PrintHello
TurnOnPower
VerifyFrequency
TurnOffPower
etc...
I want these scripts to be simple for a non-programmer to write. I don't want them to have to know what a class is or how it works. IronPython is really just there so that some basic operations like for, do, if, and a basic function definition don't require my writing a compiler for my DSL.

You should be able to do something like:
var objOps = _engine.Operations;
var lib = new Lib();
foreach (string memberName in objOps.GetMemberNames(lib)) {
_scope.SetVariable(memberName, objOps.GetMember(lib, memberName));
}
This will get all of the members from the lib objec and then inject them into the ScriptScope. This is done w/ the Python ObjectOperations class so that the members you get off will be Python members. So if you then do something similar w/ IronRuby the same code should basically work.

Related

Expose global singletons to CSharpScripts

I want to use the Roslyn Scripting Engine to provide a scripting engine for
our Software. Our software exposes some of it's api as singletons. However i cannot access those statics in the executed code.
For example i want to do something like this in script:
IOManager.Instance.DoWork(...);
When i do this:
var scriptContent = "IOManager.Instance.DoWork(...);
var options = ScriptOptions.Default;
options.AddReference(this.GetType().Assembly);
var script = CSharpScript.Create(scriptContent, options);
await script.RunAsync();
I get this error:
The name 'IOManager' does not exist in the current context
I thought maybe adding a reference to the current assembly might fix this problem. But it doesn't. I also know, that it is possible to set a global object to the script context. But i want to expose all statics/singletons accessible where i execute the script, to the script itself.
Thank you for your help.
You need to add the import for IOManager in your script:
var script = CSharpScript.Create( "IOManager.Instance.DoWork(...)" , ScriptOptions.Default.AddImports( "Namespace for IOManager" ) );

How to load referenced script libraries from a Roslyn script file?

I figured out I cannot load one script library from another easily:
module.csx
string SomeFunction() {
return "something";
}
script.csx
ExecuteFile("module.csx");
SomeFunction() <-- causes compile error "SomeFunction" does not exist
This is because the compiler does not know of module.csx at the time it compiles script.csx afaiu. I can add another script to load the two files from that one, and that will work. However thats not that pretty.
Instead I like to make my scripthost check for a special syntax "load module" within my scripts, and execute those modules before actual script execution.
script.csx
// load "module.csx"
SomeFunction()
Now, with some basic string handling, I can figure out which modules to load (lines that contains // load ...) and load that files (gist here https://gist.github.com/4147064):
foreach(var module in scriptModules) {
session.ExecuteFile(module);
}
return session.Execute(script)
But - since we're talking Roslyn, there should be some nice way to parse the script for the syntax I'm looking for, right?
And it might even exist a way to handle module libraries of code?
Currently in Roslyn there is no way to reference another script file. We are considering moving #load from being a host command of the Interactive Window to being a part of the language (like #r), but it isn't currently implemented.
As to how to deal with the strings, you could parse it normally, and then look for pre-processor directives that are of an unknown type and delve into the structure that way.
Support for #load in script files has been added as of https://github.com/dotnet/roslyn/commit/f1702c.
This functionality will be available in Visual Studio 2015 Update 1.
Include the script:
#load "common.csx"
...
And configure the source resolver when you run the scripts:
Script<object> script = CSharpScript.Create(code, ...);
var options = ScriptOptions.Default.WithSourceResolver(new SourceFileResolver(new string[] { }, baseDirectory));
var func = script.WithOptions(options).CreateDelegate()
...

How to Embed the perl interpreter in a C# Program

I realize that I have to DllImport the perlembed methods
perl_parse
perl_alloc
perl_free
etc.,
But not sure how to marhsall the function arguments for using it with DLLImport especially with perl_parse method.
I also realize that a related question already exists which is almost there but still the OP has solved by created a C wrapper and then using it in C#.
He says that he was not able to DLLimport PERL_SYS_INIT3.
So my question is how to properly wrap them using only C# and use it?
Look at this; I hope it will help (it was called in early version)
I got this from here (perl)
To embed a Perl interpreter in a C# program, add a reference to the COM object "Microsoft Script Control 1.0" and write code like this:
MSScriptControl.ScriptControlClass Interpreter;
Interpreter = new MSScriptControl.ScriptControlClass();
Interpreter.Language = #"PerlScript";
string Program = #"reverse 'abcde'";
string Results = (string)Interpreter.Eval(Program);
The above is equivalent to the following Perl script, which embeds a Perl interpreter within a Perl interpreter:
use Win32::OLE;
my $Interpreter;
$Interpreter = Win32::OLE->new('ScriptControl');
$Interpreter->{Language} = 'PerlScript';
my $Program = "reverse 'abcde'";
my $Results = $Interpreter->Eval($Program);

Why do 'requires' statements fail when loading (iron)ruby script via a C# program?

IronRuby and VS2010 noob question:
I'm trying to do a spike to test the feasibility of interop between a C# project and an existing RubyGem rather than re-invent that particular wheel in .net. I've downloaded and installed IronRuby and the RubyGems package, as well as the gem I'd ultimately like to use.
Running .rb files or working in the iirb Ruby console is without problems. I can load the both the RubyGems package, and the gem itself and use it, so, at least for that use case, my environment is set up correctly.
However, when I try to do the same sort of thing from within a C# (4.0) console app, it complains about the very first line:
require 'RubyGems'
With the error:
no such file to load -- rubygems
My Console app looks like this:
using System;
using IronRuby;
namespace RubyInteropSpike
{
class Program
{
static void Main(string[] args)
{
var runtime = Ruby.CreateRuntime();
var scope = runtime.ExecuteFile("test.rb");
Console.ReadKey();
}
}
}
Removing the dependencies and just doing some basic self-contained Ruby stuff works fine, but including any kind of 'requires' statement seems to cause it to fail.
I'm hoping that I just need to pass some additional information (paths, etc) to the ruby runtime when I create it, and really hoping that this isn't some kind of limitation, because that would make me sad.
Short answer: Yes, this will work how you want it to.You need to use the engine's SetSearchPaths method to do what you wish.
A more complete example
(Assumes you loaded your IronRuby to C:\IronRubyRC2 as the root install dir)
var engine = IronRuby.Ruby.CreateEngine();
engine.SetSearchPaths(new[] {
#"C:\IronRubyRC2\Lib\ironruby",
#"C:\IronRubyRC2\Lib\ruby\1.8",
#"C:\IronRubyRC2\Lib\ruby\site_ruby\1.8"
});
engine.Execute("require 'rubygems'"); // without SetSearchPaths, you get a LoadError
/*
engine.Execute("require 'restclient'"); // install through igem, then check with igem list
engine.Execute("puts RestClient.get('http://localhost/').body");
*/
Console.ReadKey();

Embedding IronPython in a C# application - import error on urllib

I have a Python file with as content:
import re
import urllib
class A(object):
def __init__(self, x):
self.x = x
def getVal(self):
return self.x
def __str__(self):
return "instance of A with value '%s'" % (self.getVal())
I also have a simple C# console project with the following code:
engine = Python.CreateEngine();
ScriptSource source = engine.CreateScriptSourceFromFile("test.py");
ScriptScope scope = engine.CreateScope();
ObjectOperations op = engine.Operations;
source.Execute(scope); // class object created
object klaz = scope.GetVariable("A"); // get the class object
object instance = op.Call(klaz, "blabla waarde"); // create the instance
object method = op.GetMember(instance, "getVal"); // get a method
string result = (string)op.Call(method); // call method and get result (9)
Console.WriteLine("Result: " + result); //output: 'Result: blabla waarde'
(I got this from this stackoverflow querstion and answer)
If I leave out the the import urllib statement in the Python file everything works fine. (meaning it finds the re module)
But as soon as i either add import urllib or import urllib2 I get the following exception:
ImportException was unhandled
No module named urllib
So somehow it can't find the urllib. I checked the IronPython lib folder and both urllib and urllib 2 are definitely there.
The same exception gets thrown when I import urllib in the C# code. (engine.ImportModule("urllib");)
Any ideas?
I'd like to manage the imports in the python code and not in the C# code.
(So I'd like to avoid stuff like this: engine.ImportModule("urllib");)
Edit:
Some extra info on what I'm actually going to use this for (maybe someone has an alternative):
I will have a main C# application and the python scripts will be used as extensions or plugins for the main application.
I'm using Python so that I don't need to compile any of the plugins.
I believe that 'Lib' being on sys.path from the interactive console is actually done inside ipy.exe - and when embedding you will have to add the path manually. Either the engine or the runtime has a 'SetSourcePaths' (or similar) method that will allow you to do this.
I face the same problem. Following "Tom E's" suggestion in the comments to fuzzyman's reply I could successfully resolve the issue. The issue seems to be it is not able resolve the location of the urllib.py. We need to set it.
You can check the following link for the question and answer.
The version of CPython you're importing from must match your IronPython version. Use CPython v2.5 for IronPython 2.0, or v2.6 for IronPython 2.6.
Try this:
import sys
sys.path.append(r'\c:\python26\lib') # adjust to whatever version of CPython you have installed.
import urllib

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