Chapter 6. Literal Expressions

Table of Contents
6.1. Boolean literal expressions
6.2. Character literal expressions
6.3. String literal expressions
6.4. Integer literal expressions
6.5. Floating point literal expressions
expression ==>
        bool_literal_expression | char_literal_expression | str_literal_expression  | int_literal_expression | flt_literal_expression

There are special lexical forms for literal expressions which define boolean, character, string, integer, and floating point values. These literal forms all have a concrete type derived from the syntax; typing of literals is not dependent on context. Sather does not do implicit type coercions (such as promoting an integer to floating point when used in a floating point context.) Types must instead be promoted explicitly by the programmer. This avoids a number of portability and precision issues (for example, when an integer can't be represented by the floating point representation.)

Example 6-1. These two expressions are equivalent. In the first, the 'd' is a literal suffix denoting the type. In the second, '3.14' is the literal and '.fltd' is an explicit conversion.

3.14d     -- A double precision literal
3.14.fltd -- Single, but converted

6.1. Boolean literal expressions

Example 6-2. Examples:

bool_literal_expression ==>
        true | false

BOOL objects represent boolean values (See Type). The two possible values are represented by the boolean literal expressions: 'true' and 'false'.