Professional IronPython

Understanding the Hosting APIs Usage Levels
The DLR documentation specifies that most developers will use the Hosting APIs at one of three 
levels that are dictated by application requirements. Here are the three basic levels.
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Basic code: The basic code level (Level 1 in the documentation) relies on a few basic types to 
execute code within scopes. The code can interact with variable bindings within those scopes.
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Advanced code execution: The next level (Level 2 in the documentation) adds intermediate 
types that provide additional control over how code executes. In addition, this level supports 
using compiled code in various scopes and permits use of various code sources.
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Support overrides: The final level (Level 3 in the documentation) provides methods to override 
how DLR resolves filenames. The application can also use custom source content readers, reflect 
over objects for design-time tool support, provide late bound variable values from the host, and 
use remote 
ScriptRuntime
objects.
The concept of a 
ScriptRuntime
object is central to working with the Hosting APIs. A host always 
begins a session by creating the 
ScriptRuntime
object and then using that object to perform tasks. 
You can create a 
ScriptRuntime
object using several methods. Of course, the easiest method is to 
use the standard constructor, which requires a 
ScriptRuntimeSetup
object as input. It’s also pos-
sible to create a 
ScriptRuntime
object using these methods
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ScriptRuntime.CreateFromConfiguration()
: A factory method that lets you use a pre-
configured scope to create the 
ScriptRuntime
object. In fact, this factor method is just short 
for 
new ScriptRuntime(ScriptRuntimeSetup.ReadConfiguration())
.
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