Identifier (computer languages)

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Identifier" computer languages – news · newspapers · books · scholar · JSTOR (September 2019) (Learn how and when to remove this message)

This article is missing information about Unicode character and UAX31 recommendation. Please expand the article to include this information. Further details may exist on the talk page. (March 2021)

In computer

.

Lexical form

Which character sequences constitute identifiers depends on the

, so lexing could be context-sensitive.

In most languages, some character sequences have the lexical form of an identifier but are known as

PL/1

, the distinction is not clear.

Semantics

The scope, or accessibility within a program of an identifier can be either local or global. A global identifier is declared outside of functions and is available throughout the program. A local identifier is declared within a specific function and only available within that function.[1]

For implementations of programming languages that are using a

the compiled program contains references to memory addresses and offsets rather than the textual identifier tokens (these memory addresses, or offsets, having been assigned by the compiler to each identifier).

In languages that support

.

Compilers and interpreters do not usually assign any semantic meaning to an identifier based on the actual character sequence used. However, there are exceptions. For example:

• In
  expressions
  .
• In
  Ruby a variable is automatically considered immutable
  if its identifier starts with a capital letter.
• In Go, the capitalization of the first letter of a variable's name determines its visibility (uppercase for public, lowercase for private).

In some languages such as Go, identifiers uniqueness is based on their spelling and their visibility.^[2]

In HTML an identifier is one of the possible attributes of an HTML element. It is unique within the document.

See also

• Naming convention (programming)

References