V22 Macro Preprocessor

V22 introduces the full macro expansion engine. Macros are expanded before the lexer runs, so they can generate any PB code including declarations, statements, and expressions.

Object-Like Macros: #DEFINE

Simple text-replacement macros. Every occurrence of name in subsequent source is replaced with value.

#DEFINE MAX_COUNT 100
#DEFINE APP_NAME "MyApp"

LOCAL i AS LONG
FOR i = 1 TO MAX_COUNT
    PRINT APP_NAME
NEXT i

Single-Line Function Macros

Expression macros that expand inline with argument substitution.

MACRO Add1(x) = (x + 1)
MACRO Square(n) = (n * n)
MACRO Max(a, b) = IIF((a) > (b), (a), (b))

LOCAL v AS LONG
v = Add1(10)       ' Expands to: v = (10 + 1)
v = Square(v)      ' Expands to: v = (v * v)

Multi-Line Statement Macros

Block macros that expand to multiple statements. Arguments are substituted by name.

MACRO SAY(text)
    PRINT text
END MACRO

MACRO SwapVars(a, b)
    LOCAL t AS LONG
    t = a
    a = b
    b = t
END MACRO

FUNCTION PBMAIN() AS LONG
    LOCAL x, y AS LONG
    x = 10 : y = 20
    SwapVars(x, y)
    SAY("Hello from macro!")
END FUNCTION

MACROFUNCTION with MACROTEMP

Function-like macros that can declare temporary variables with MACROTEMP. MACROTEMP generates a unique name for each expansion, preventing collisions.

MACROFUNCTION Twice(x)
    MACROTEMP t
    LOCAL t AS LONG
    t = x * 2
END MACRO = t

FUNCTION PBMAIN() AS LONG
    LOCAL a, b AS LONG
    a = Twice(5)     ' a = 10, uses unique temporary
    b = Twice(a)     ' b = 20, uses different unique temporary
END FUNCTION

Recursive Macro Protection

The preprocessor detects and rejects recursive macro invocations and excessive expansion depth (default limit: 256 levels).

' This produces a diagnostic error, not infinite expansion
' #DEFINE X Y
' #DEFINE Y X
' PRINT X    ' Error: recursive macro expansion

#INCLUDE ONCE and #INCLUDEONCE

Prevents duplicate inclusion of the same file. Useful for header files included from multiple locations. Missing-file diagnostics are emitted when the included file cannot be found.

#INCLUDE ONCE "win32api.inc"
#INCLUDEONCE "mytypes.pbi"

#COMPILE DLL and GUI Mode Rejection

V22 explicitly rejects unsupported compile modes with a clear diagnostic instead of silently producing a wrong EXE type:

' #COMPILE DLL "mylib.dll"      ' Error: DLL output not yet implemented
' #COMPILE EXE "app.exe" GUI     ' Error: GUI subsystem not yet implemented

Predefined V22 Symbol

V22 defines PBXA64_V22 as a conditional symbol, allowing version-gated code:

#IF %DEF(PBXA64_V22)
    PRINT "Running under PBXA64 V22 or later"
    ' Use V22 macro features
#ELSE
    PRINT "Older version - macros not available"
#ENDIF

#UNDEF

Removes a previously defined conditional symbol or #DEFINE macro.

#DEFINE DEBUG 1
' ... debug code here ...
#UNDEF DEBUG
' Debug code no longer active

Diagnostics