2 Character Set and Source File Encoding

2.1  Character Set

The syntax of Erlang tokens allow the use of the full ISO-8859-1 (Latin-1) character set. This is noticeable in the following ways:

• All the Latin-1 printable characters can be used and are shown without the escape backslash convention.

• Unquoted atoms and variables can use all Latin-1 letters.

The following tokens are allowed to also use Unicode characters outside of the Latin-1 range:

• String literals. Example: "√π"

• Character literals. Example: $∑

• Comments in code.

• Quoted atoms. Example: 'μs'

• Function names. Example: 's_to_μs'(S) -> S * 1_000_000.

Atoms used as module names, application names, and node names are restricted to the Latin-1 range.

2.2  Source File Encoding

The Erlang source file encoding is selected by a comment in one of the first two lines of the source file. The first string that matches the regular expression coding\s*[:=]\s*([-a-zA-Z0-9])+ selects the encoding. If the matching string is an invalid encoding, it is ignored. The valid encodings are Latin-1 and UTF-8, where the case of the characters can be chosen freely.

The default Erlang source file encoding if no valid coding comment is present is UTF-8.

Two examples, both selecting Latin-1 as the source file encoding:

%% For this file we have chosen encoding = Latin-1

%% -*- coding: latin-1 -*-