Most identifiers allowed by other programming
languages are also acceptable to Scheme. The precise rules for forming
identifiers vary among implementations of Scheme, but in all
implementations a sequence of letters, digits, and “extended alphabetic
characters” that begins with a character that cannot begin a number is
an identifier. In addition,
... are identifiers.
Here are some examples of identifiers:
lambda q list->vector soup + V17a <=? a34kTMNs the-word-recursion-has-many-meanings
Extended alphabetic characters may be used within identifiers as if they were letters. The following are extended alphabetic characters:
! $ % & * + - . / : < = > ? @ ^ _ ~
See section Lexical structure for a formal syntax of identifiers.
Identifiers have two uses within Scheme programs: