Names (field names, for example) are case-insensitive and consist of multiple words, numbers, or hyphens. A name should start with a word and should finish with either word or number.

Name parts can be separated by any number of space characters (Unicode Zs, not a new line characters), but this is not always required and sometimes prohibited or discouraged (may be so with hyphens).

Space is not a part of the name. Rather it’s just a syntactic method of separating different parts of the name.

Note that comments and underscore are not allowed within a name.


Word is a sequence of any Unicode letters.

These are valid words:


When the name contains two sequential words it is necessary to separate them by space, like this:

Hello World

or this:

Hello World


A number is a sequence of decimal digits (0...9).

The name can not start with a number. So, the following is not a valid name:


When the number follows a word, there is no need to place the space between them. So the following names are the same:

name 2

The same rule applies to the word following the number. The following names are the same:

render 3d
render 3 d
render3 d


Names may contain hyphens (-). There are multiple hyphen characters in Unicode. o42a makes no difference between them internally, but applies different syntactic rules for the sake of grammatical correctness. The following hyphen symbols recognized: | U+002D | HYPHEN-MINUS | | U+2010 | HYPHEN | | U+2011 | NON-BREAKING HYPHEN |

The following rules apply to the hyphen usage in names:

  • the name should not start with a hyphen,
  • the name should not end with a hyphen,
  • the hyphen should not follow another hyphen,
  • no spaces allowed before HYPHEN-MINUS,
  • a space before HYPHEN or NON-BREAKING HYPHEN is discouraged and issues a warning,
  • a space after NON-BREAKING HYPHEN is discouraged and issues a warning.

To write a subtraction operator or unary minus operator, just place a space before the HYPHEN MINUS sign.

So, the following are not a valid names:

plug - in
built -in

Examples of valid names: