TAL Programmer's Guide

Operands
Using Expressions
5–2 096254 Tandem Computers Incorporated
Operands Operands in expressions can be items such as variables, constants, LITERALs, and
function invocations.
The following subsections describe identifiers, data types, variables, constants,
LITERALs, and functions, followed by arithmetic expressions and conditional
expressions.
Identifiers Identifiers are names you declare for objects such as variables, LITERALs, and
procedures (including functions). You can form identifiers that:
Are up to 31 characters long
Begin with an alphabetic character, an underscore (_), or a circumflex (^)
Contain alphabetic characters, numeric characters, underscores, or circumflexes
Contain lowercase and uppercase characters (the compiler treats them all as
uppercase)
Are not reserved keywords, which are listed in Table 5-1.
Can be nonreserved keywords, except as noted in Table 5-2.
To separate words in identifiers, use underscores rather than circumflexes.
International character-set standards allow the character printed for the circumflex to
vary with each country.
Do not end identifiers with an underscore. The trailing underscore is reserved for
identifiers supplied by the operating system.
The following identifiers are correct:
a2
myprog
_23456789012_00
name_with_exactly_31_characters
The following identifiers are incorrect:
2abc !Begins with number
ab%99 !Illegal symbol
Variable !Reserved word
This_name_is_too_long_so_it_is_invalid !Too long
Though allowed as TAL identifiers, avoid identifiers such as:
Name^Using^Circumflexes
Name_Using_Trailing_Underscore_