Keywords

The PRX language has several reserved keywords.

Boolean Constants

These constants are used to express positive or negative values for the BOOL-type.

Keyword	Description
TRUE	Positive boolean value
FALSE	Negative boolean value

/* set variables with boolean values */
SET &TEST_VAR1 = TRUE;
SET &TEST_VAR2 = FALSE;

/* check for variables */
IF(&TEST_VAR1 EQ TRUE AND
   &TEST_VAR2 NE TRUE);
   CALL SAY("This works!");
IF(END);

Current & Focus

Keyword
THIS	Value of the object provided by the last command
FOCUS	Value of the currently focused object

Comparison Operators

These operators are mainly used in conditional statements.

Operator	Description
EQ	Equal
NE	Not equal
LT	Less than
LE	Less than or equal
GT	Greater than
GE	Greater than or equal
IN	Contains (for lists)

/* define test variables */
SET &TEST_VAR1 = TRUE;
SET &TEST_VAR2 = 3;

/* operators in a rule */
CALL
FILTER
    TEST = &TEST_VAR1 EQ TRUE
EXEC
    SAY("Variable is true");
    
/* operators in an IF-statement */
IF(&TEST_VAR2 GT 2);
    CALL SAY("Variable is greater than 2");
IF(END);

Logical Operators

These operators extend the functionality of the comparison operators.

Operator	Description
AND	Logical AND operator
OR	Logical OR operator
NOT	Negation operator

/* define variables */
SET &TEST_VAR1 = 3;
SET &TEST_VAR2 = 6;

/* use combination operators */
IF(&TEST_VAR1 EQ 3 AND &TEST_VAR2 GT 4);
    CALL SAY("Both conditions are true");
IF(END);

/* use negation operator */
IF(NOT &TEST_VAR1 EQ 3);
    CALL SAY("Variable isn't equal to 3");
IF(END);

Statement Filters

Keyword	Description
FIRST	First statement of the job control
LAST	Last statement of the job control