Cast functions

• PMP does not allow to cast an assigned variable, except with the BYTES keyword, see below.

integer-cast-function = ( BYTE | CHAR | SHORTINT | WORD | INTEGER | LONGWORD | LONGINT ) "(" expression ")" .

If <expression> returns an integer type value, cast (truncate or expand) the expression result to the specified format.

If <expression> returns a floating point value, convert (and truncate) the expression result to the specified format. A truncation warning may occur.

float-cast-function = ( SINGLE | REAL ) "(" expression ")" .

Convert the expression result to the specified float format.

integer-cast-as-array = BYTES "(" variable ")" "[" index-expression "]"  .
integer-assign-with-cast = BYTES "(" variable ")" "[" index-expression "]" ":=" expression .

NEW! (V2.1): The BYTES keyword may be used to access any <variable> as an ARRAY[0..SIZEOF(<variable>)-1] OF BYTE. It may be used to cast an assigned variable and to read any variable as an ARRAY as well. For an ARRAY [...] OF BOOLEAN, the number of elements must be a multiple of 8.

VAR
 LW: LONGWORD;
 W0: WORD;
 F0: REAL;
…
  W0 := WORD(LW); // avoids truncation warning
 F0 := REAL(W0) * 100000; // computes in float format
…
 BYTES(LW)[1] := $55; // assigns $55 to bits 8..15 of LW
 W0 := BYTES(LW)[2]; // assigns W0 with bits 16..23 of LW