Pseudo SET, IN keyword

PMP does not support the standard Pascal SET, but uses the SET syntax for special purposes like bit masks:

[BitA, BitB, BitC..BitD] defines a constant bit mask where the bit positions BitA and BitB are set, along with all bits from BitC to BitD.

The standard IN keyword may be used to check a bit within any expression result as a pseudo SET.

Special behavior: If an element is a BOOLEAN variable, the bit number of this variable is used.

• Since this special construction applies only to simple variables or expressions, it is limited to 32-bit values and may be used in constant declarations or in any expression.

When the assigned variable is a SFR, any of its fields values may be defined inside the pseudo-set:

OSCCON := [IOSCF = 0b110, SCS];

VAR
  IO_Bit: boolean @ PORTC.1;
  VarLong: longint;
  VarByte: byte;

CONST
  BitA = 2; BitB = 4;
 
  BitMask = [BitA, BitB, IO_Bit]; { Equivalent to [2, 4, 1]: constant b'00010110' }
…
  VarLong := BitMask;
  VarByte := BitB;
 
  IF 2 IN BitMask THEN // Evaluated as always True at compile time
    IF 4 IN [1, BitB..31] THEN // Evaluated as always True at compile time
      IF BitA IN VarLong THEN  // True since bit 2 is set in VarLong
        IF VarByte IN VarLong THEN // True since VarByte=4 and bit 4 is set in VarLong
…