Failure to compile *.inc with simple "If" statement

The issue of failure to compile the macro containing a simple "if" statement in a .inc file can arise due to several factors related to how macros are defined and used. Here are key considerations:

1. Macro Definition Syntax:
   Ensure the macro syntax is correct. Macros are defined using #define, and any spaces within the expression in the macro definition can cause syntax errors. For example:

   #define TestIf(%arr) if (%arr>0) {QUIT 5}
   

   The entire expression, if (%arr>0) {QUIT 5}, should not contain spaces that disrupt the syntax [1][2].

2. Including Macros Properly:
   The targeted .inc file must be included correctly at the top of the class definition or method where the macro is used. The inclusion syntax is:

   include MacroFileName
   

   Make sure the .inc file name is referenced without the .inc suffix [1][3].

   Additionally, when using macros in methods directly, you may need a specific inclusion inside the body of that method if required at compile time [1].

3. Preprocessor Directive Spacing:
   It’s critical that spaces do not appear unnecessarily in expressions in macro definitions. For example:

   #define TestIf(%arr) if %arr>0 QUIT 5
   

   Spaces must follow conventions depending on where they appear in definitions and expressions [1].

4. Macro Symbol and Order:
   When invoking macros ($$$macroname), ensure they are defined earlier in the code or included properly in the .inc file. Undefined macros or incorrectly referenced ones will lead to compilation errors [1].

5. Use of System Macros:
   If the macro references system macros (e.g., $SYSTEM or $GET), verify that the appropriate system .inc files are included in the class. For example:

   include %occStatus
   

   Missing system includes can cause recognized macros (such as $$$OK) to fail [4].

Addressing these aspects should resolve the compilation issues for a macro with an "if" statement. Let me know if you need further clarification or examples.

Sources:

I think you may lack a space before your macro use. Any line of actual code other than a line labels needs to start with a space or tab.

You might be having problems with some of the unusual syntax of ObjectScript.

Like other languages created in the 1960s (E.g., FORTRAN IV and PL/I), ObjectScript does not have any reserved words.  The word 'if' can be a command if it appears where a command is specified; it can be local variable if it appears where an expression value is expected; it can sometimes be a global variable or program name if it appears after '^';  it can be a function name if it appears after '$$';  it can be a macro name if it appears after '$$$';  it be a routine or procedure name if it appears after the 'do' command; if can sometimes be a method or a property name if it appears after '.'; etc.

Your macros
    #define TestIf(%arr)    if %arr>0 QUIT 5          ;; legacy IF command
    #define TestIf(%arr)    if (%arr>0) {QUIT 5}     ;; more modern IF command
looks as if TestIf should be expanded where a command is expected so that it conditionally executes the command 'QUIT 5' which would exit the current function with a return value of 5.

However, your macro placement
    set a = $$$TestIf(3)
looks like $$$TestIf is going to be an expression containing a value for the right side of an assignment (a SET command).  It expands as
    set a = if 3 < 0 QUIT 5
which is a syntactically correct assignment of 'a' assigned the value of the variable 'if'  and that 'set' command is followed by a command named '3' which is bad syntax.

Your macro
#define logDebug(%arr) $SELECT(^GlFSL("Debug")>0:Entry^HS.Local.VA.Util.Log(%arr,,"D"),:QUIT)

looks like a macro  containing the built-in '$select' function and the macro should expand into conditional expression (as opposed to a macro containing the command 'if' which should expand in to a conditional statement.)  The first $select argument ^GlFSL("Debug")>0:Entry^HS.Local.VA.Util.Log(%arr,,"D") evaluates ^GlFSL("Debug")>0 and it that comparison is true, the $select evaluates Entry^HS.Local.VA.Util.Log(%arr,,"D") as the final value of the $select expression.  If the selector of the first argument is false then $select goes on the second argument ,:QUIT.  This has the syntax for the default value of a argument of the built-in $case function rather than be correct syntax for a $select argument.  For a $select you would write 1:QUIT which would return the value of the QUIT variable.  However,  I suspect you might have wanted a QUIT command which would terminated the current routine/procedure.  In that case you should write  the conditional commands
    if ^GlFSL("Debug")>0 then { set temp=Entry^HS.Local.VA.Util.Log(%arr,,"D")} else {QUIT}
if you do not execute the QUIT command then you can continue executing the next command line using the conditionally set 'temp' variable.

Statement "set a = $$$TestIf(3)" is included into a classmethod with no other code in. Expected output 5

What is the expected result for the next operator?

set a = $$$TestIf(-3)