The simplest type of expression is a variable name or a constant.
You name a variable using a letter or an underscore, followed by zero-or-more letters, digits, or underscores. All names in Glish are case-sensitive, so ``foo_123" and ``Foo_123" are different names. See Appendix A, page , for the Glish syntax and grammar.
Variable names simply evaluate to the present value (and type) of the variable; if the variable hasn't been previously set, Glish generates a warning and sets it to F.
See § 3.2.1, § 3.3.1, and § 3.4.1 for creating numeric, string, and record constants, and § 3.1.4, page , for creating vector constants.