Pico (programming language)

Pico is a programming language developed at the Software Languages Lab at Vrije Universiteit Brussel, intended to be simple, powerful, extensible, and easy to read. The language was created to introduce the essentials of programming to non-computer science students.

Pico can be seen as an effort to generate a palatable and enjoyable language for people who do not want to study hard for the elegance and power of a language. They have done it by adapting Scheme's semantics.

While designing Pico, the Software Languages Lab was inspired by the Abelson and Sussman's book "Structure and Interpretation of Computer Programs". Furthermore, they were influenced by the teaching of programming at high school or academic level.

Pico should be interpreted as 'small', the idea was to create a small language for educational purposes.

Language elements
De Meuter, Gonzalez, and D'Hondt describe the Pico syntax as being "two-tiered." The first layer consists of simple rules for writing small programs in a functional programming style.

Comments
Comments are surrounded by backquotes ("`").

Variables
Variables are dynamically typed; Pico uses static scope. var: value

Functions
Functions, like everything in Pico, are first-class objects, meaning they can be assigned to variables and passed to and returned from functions. Also, there are no anonymous functions in Pico; functions must have a name. For example, a function,, with two parameters,   and  , can be defined as: func(param1, param2): ...

Functions can be called with the following syntax: func(arg1, arg2)

Operators
Operators can be used as prefix or infix in Pico: +(5, 2) 5 + 2

Data types
Pico has the following types: string, integer, real and tables.

It does not have a native char type, so users should resort to size 1 strings.

Tables are compound data structures that may contain any of the regular data types.

Boolean types are represented by functions (as in lambda calculus).

Conditional evaluation
Only the usual if statement is included if(condition, then, else)

Code snippets
display('Hello World', eoln)

max(a, b): if(a < b, b, a)

` http://www.paulgraham.com/accgen.html ` foo(n): fun(i): n := n+i

Mac OS, Mac OS X

 * MacPico
 * XPico

Windows

 * WinPico This version is buggy
 * WinPico stable

Linux

 * TextPico for Linux

Cross-platform

 * sPico for DrScheme