Beyond Compilers

Compiler technology is not just for Creating Compilers

• Many common applications include built-in macro facilities which often feature full-blown scripting engines

• Applications that have to read data files with complicated formats use parsers

Adding Scripting Capability to Applications

• Do your users need to automate certain tasks in your application? Don’t write a custom macro facility; make your application scriptable!

• Ultimate Example: Microsoft Office/VBA

Don’t Invent Your Own Language

Why invent a language and write a parser when you can use a scripting engine

Java: Scripting API

• Java Scripting API (https://docs.oracle.com/javase/9/docs/api/javax/script/package-summary.html)

• Supports: Javascript (built in), Python, Tcl, …

• Demo: /examples/beyondcompilers/scriptdemo

.NET: Dynamic Language Runtime

• Overview of DLR

• IronPython Demo

  1. Create a .NET WPF App
  2. Install IronPython NuGet Package

  3. Initialize engine

     var engine = Python.CreateEngine();
     var scope = engine.CreateScope();             
     

  4. Inject objects into scope of script

     scope.SetVariable("varname", var);
     ScriptSource source = engine.CreateScriptSourceFromString("print(varname)");     
     

  5. Execute script

     source.Execute(scope);
     

A Bit of History

http://www.softwarepreservation.org/projects/FORTRAN/video/FORTRAN-1982.wmv/view

History of Fortran (~10 min) Local: “G:\CpS450\videos\FORTRAN-1982.wmv”