Scripting Languages Intro Jan Stelovsky, ICS 215

Wikipedia A scripting language, script language or extension language is a programming language that allows control of one or more software applications. "Scripts" are distinct from the core code of the application, as they are usually written in a different language and are often created or at least modified by the end-user. Scripts are often interpreted from source code or bytecode, whereas the applications they control are traditionally compiled to native machine code. Scripting languages are nearly always embedded in the applications they control.

Comment from stackoverflow:stackoverflow – You will notice the use of "usually", "often", "traditionally" and "nearly always" - these all tell you that there is no set of distinct attributes that make a specific language a "scripting language".

Scripting vs. “Programming” Languages Scripting languages are Programming languages (PL) interpreted vs. compiled – slow vs. fast but: Java – a PL is hybrid – compiled to bytecode bytecode is common to all hardware platforms bytecode is then interpreted – JIT even compiles to “native” code dynamically but: LISP – a PL - is interpreted but: scripting languages became hybrid/compiled – all JavaScript scripts are nowadays compiled

Hybrid Processing program script bytecode native Windows Intel native Mac Intel/Motorola native Linux Intel

Scripting vs. “Programming” Languages cont. scripting languages often operate other programs, or the operating system (OS), e.g. Windows, or other applications, e.g. the browser – batch “shells” on Unix – Applescript operating other applications but often programs in PL can execute or at least create scripts for scripting languages but does JavaScript “operate another program” – the browser?

Other Aspects verbose vs. terse – PL are typically terse, vs. Applescript but – but most languages adopted C syntax: C, C++, Java, JavaScript, even Ruby

Other Uses of Scripting Languages CoffeeScript is a better JavaScript – classes: inheritance consistency alleviates JavaScript quirks – == and === – is variable defined? – what’s variable’s type needs to be translated to JavaScript

PL Charts How did PLs develop – typical chart typical chart – mostly C as “grandfather” Java = C++-- – consider trends (innovation, density) book publishers, e.g. O’ReillyO’Reilly –

Traditional PL Chart (top)

Traditional PL Chart (bottom)

O’Reilly PLs & Books

O’Reilly PLs

Most Recent O’Reilly PL Books 8 out of 13 newer PLs (=60%) Note: JavaScript ~= ECMA Script ~= ActionScript

215, ICS and PLs Popularity ICS out of 11 most popular PLs (mpPLs) 24% of mpPLs ICS 7 out of 11 mpPLs 55% of mpPLs

Conclusion The differences between Scripting Languages and Programming Languages are getting more and more blurred languages are becoming compiled or at least hybrid languages often operate OS or other applications – e.g. access to file system our distinction is mainly historical – Java (Pascal) and C++ are taught in intro courses – we need to expose students to other languages ICS exposes you to most of the trending PLs – already in undergraduate curricullum – in particular in ICS 215 (and ICS 315)

Our Definition now – JavaScript – Ruby – PHP – Python – Perl in future – other new programming languages as they become important