Editing Standard library (section)

{{Short description|Library provided with a programming language to provide common services}}
{{refimprove|date=May 2019}}

In [[computer programming]], a '''standard library''' is the [[library (computing)|library]] made available across [[Programming language implementation|implementations]] of a [[programming language]]. Often, a standard library is specified by its associated [[programming language specification]], however, some are set in part or whole by more informal practices of a language community.

Some languages define a core part of the standard library that must be made available in all implementations while allowing other parts to be implemented optionally.

As defined with the core language aspects, the line between the core language and its standard library is relatively subtle. A [[programmer]] may confuse the two aspects even though the language designers intentionally separate the two.

The line between the core language and its standard library is further blurred in some languages by defining core language constructs in terms of its standard library. For example, [[Java (programming language)|Java]] defines a [[string literal]] as an instance of the java.lang.String class. [[Smalltalk]] defines an anonymous function expression (a "block") as an instance of its library's BlockContext class. [[Scheme (programming language)|Scheme]] does not specify which portions must be implemented as core language vs. standard library.