ST is a structured literal programming language. A ST program is a list of statements. Each statement describes an action and must end with a semi-colon (";").
The presentation of the text has no meaning for a ST program. You can insert blank characters and line breaks where you want in the program text.
Comments
Comment texts can be entered anywhere in a ST program. Comment texts have no meaning for the execution of the program. A comment text must begin with "(*" and end with "*)". Comments can be entered on several lines (i.e. a comment text may include line breaks). Comment texts cannot be nested.
Expressions
Each statement describes an action and may include evaluation of complex expressions. An expression is evaluated:
- from the left to the right
- according to the default priority order of operators
- the default priority can be changed using parenthesis
Arguments of an expression can be:
- declared variables
- constant expressions
- function calls
Statements
Below are available basic statements that can be entered in a ST program:
- assignment
- function block calling
Below are the available conditional statements in ST language:
- IF / THEN / ELSE (simple binary
switch)
- CASE (enumerated switch)
Below are the available statements for describing loops in ST language:
- WHILE (with test on loop entry)
- REPEAT (with test on loop exit)
- FOR (enumeration)