Compiler conditional statements

Selected portions of PL/MX source can be conditionally compiled by using compiler conditional statements and the PLMX_CCFLAGS command-line argument.

Syntax

$IF conditional-boolean-expression $THEN
  source
[$ELSIF conditional-boolean-expression $THEN source]
[$ELSE source]
$END

conditional-boolean-expression :=
   [(] [unary-boolean-operator] conditional-boolean-operand 
   [ binary-boolean-operator conditional-boolean-expression ] [)]

conditional-boolean-operand :=
    $$ccflags-variable
  | FALSE
  | TRUE
  | NULL
  | conditional-boolean-expression
  | conditional-comparison-expression

unary-boolean--operator := NOT

binary-boolean-operator :=
    AND
  | OR

conditional-comparison-expression := 
  conditional-arithmetic-expression relational-operator 
conditional-arithmetic-expression
  | conditional-boolean-expression relational-operator 
  conditional-boolean-expression

relational-operator :=
    =
  | <
  | <=	
  | >
  | >=
  | ^=
  | !=
  | <>
  | ~=

Examples

Where,

source: PL/MX source such as statements, comments, or additional compiler conditional statements.
conditional-boolean-expression: It is a Boolean expression as described in the syntax.
ccflags-variable: Is the name of a variable defined in the -plmx_ccflags command-line option. For more information on the plmx_ccflags option, see The Standalone Compiler.
conditional-arithmetic-expression: A numeric literal in the range -2147483647 through 2147483647 .

A simple $IF statement using the literal constant TRUE.

$IF TRUE $THEN
  --- Include this source in the compilation.
$END

A $IF statement with $ELSIF and $ELSE.

	$IF $$compileThis $THEN
   --- Include this source in the compilation.
			built_for_flag := 1;
 $ELSIF $$compileThat $THEN
	  --- Include that source in the compilation.
   built_for_flag := 2;
 $ELSE
   --- Include from here when it’s neither this nor that.
   built_for_flag := 3;
 $END