apiUi – Script grammar

Grammar

An activator consists of a list of declarations (optional), followed by an arbitrary number of executable statements.

DeclarationList

Every declaration is terminated by a semicolon.

Declaration

A declaration starts with a type specifier and is followed by an identifier. Like with C it is possible to immediately assign a value to a field by specifying an expression.

Example

timestamp ws.CurrentTime := now ();

Type

FLOAT | INTEGER | STRING | TIMESTAMP

A type is a name for a kind of data. The following table lists the supported datatypes in a declaraction within an activator.

FLOAT	A float can contain data that can be represented with floating point notation
INTEGER	Integer data is a subset of float data, only whole numbers can be represented
STRING	A string datatype is used to store a sequence of characters
TIMESTAMP	Use timestamp if you want a local field to temporarily store a date, a time or a datetime value

StatementList

( Statement )…

As with C and Pascal, statements are terminated with a semicolon

Statement

( Assignment | CompoundStatement | IfStatement | WhileStatement | VoidStatement ) ‘;’

There are five basic statements in the activator language. A CompoundStatement is merely a group of statements enclosed with a begin and end

CompoundStatement

‘{’ StatementList ‘}’ | BEGIN StatementList END

Examples

begin

ws.begin := 1;

ws.end := 2;

end

{

ws.begin := 1;

ws.end := 2;

}

IfStatement

IF Expression THEN Statement [ ELSE Statement]

Expression returns a Boolean value. If expression is True, then the first statement is executed; otherwise the second statement is executed

Examples

if ws.salary > 1000 then

ws.salary := ws.salary * 1.01;

if ws.salary > 1000 then

ws.salary := ws.salary * 1.01;

else

begin

ws.salary := ws.salary + 10;

ws.salary := ws.salary * 1.01;

end

WhileStatement

WHILE Expression DO Statement

The While statement executes Statement repeatedly. Before each iteration the Boolean expression is tested. Statement is only executed if Expression returns True.

Example

while ws.loop > 0 do

{

ws.count := ws.count + 1;

ws.loop := ws.loop – 1;

}