Editing Pico (programming language)

{{Other uses|Pico (disambiguation)}}
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{{Infobox programming language
| name = Pico
| paradigms = [[Reflective programming|Reflective]], [[Procedural programming|procedural]]
| family = [[Lisp (programming language)|Lisp]]
| designers = Theo D'Hondt<br/>Wolfgang De Meuter
| developer = [[Vrije Universiteit Brussel]]
| released = {{Start date and age|1995}}
| latest release version = 2.0
| latest release date = {{Start date and age|2007}}
| programming language = [[Scheme (programming language)|Scheme]]
| platform = [[IA-32]], [[x86-64]]
| operating system = [[Mac OS 9]], [[macOS]]; [[Linux]]–[[BSD]], [[Windows]]
| website = {{URL|pico.vub.ac.be}}
| influenced by = [[Scheme (programming language)|Scheme]], [[Smalltalk]]
}}
'''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.<ref name="pico_d&r">{{cite journal |last1=D'Hondt |first1=Theo |last2=Gonzalez |first2=Sebastian |last3=De Meuter |first3=Wolfgang |date=1 January 1999 |title=The design and rationale behind pico |url=https://www.academia.edu/509697/The_design_and_rationale_behind_pico |journal=Programming Technology Lab, Department of Computer Science, Vrije Universiteit Brussel |page= |access-date=3 December 2023}}</ref> 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 (programming language)|Scheme's]] [[Semantics (computer science)|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."<ref name="pico_d&r" /> The first layer consists of simple rules for writing small programs in a [[functional programming]] style.

=== Comments ===
Comments are surrounded by [[backquote#computer|backquote]]s ("`").

=== Variables ===
[[variable (programming)|Variables]] are dynamically [[data type|typed]]; Pico uses static [[scope (programming)|scope]].
 var: value

=== Functions ===
Functions, like everything in Pico, are [[first-class object]]s, 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.<ref name="pico_d&r" /> For example, a function, <code>func</code>, with two parameters, <code>param1</code> and <code>param2</code>, 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 (computer science)|string]], [[integer]], [[real number|real]] and [[array data type|tables]].

It does not have a native [[character (computing)#char|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]]).

=== Control structures ===
==== 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)

 `<span class="plainlinks">http://www.paulgraham.com/accgen.html</span>`
 foo(n): fun(i): n := n+i

== Implementations ==
=== Mac OS, Mac OS X ===
*[http://pico.vub.ac.be/downloads.html MacPico]
*[https://web.archive.org/web/20040221012930/http://wilma.vub.ac.be/~pvdabeel/stuff/Xpico-Snaps/ XPico]

=== Windows ===
*[http://pico.vub.ac.be/downloads.html WinPico] ''This version is buggy''
*[http://student.vub.ac.be/~nkaraogl/WinPico/ WinPico stable]

=== Linux ===
*[http://dirk.rave.org/ TextPico for Linux]

=== Cross-platform ===
*[https://web.archive.org/web/20080905092122/http://www.infogroep.be/sPico sPico for DrScheme]

==References==
{{Reflist}}

== External links ==
*{{Official website}}
*[http://soft.vub.ac.be/ Software Languages Lab]
*[http://dinf.vub.ac.be/ Department of Computer Science at VUB]
*[http://www.vub.ac.be/ VUB]
*[https://web.archive.org/web/20080905092145/http://www.infogroep.be/Pico The Infogroep Pico page]

{{Lisp programming language}}

[[Category:1997 software]]
[[Category:Programming languages created in 1997]]
[[Category:Programming languages]]
[[Category:Functional languages]]
[[Category:Educational programming languages]]
[[Category:Academic programming languages]]
[[Category:Dynamically typed programming languages]]
[[Category:Lisp programming language family]]