byVal and byRef are keywords in the declaration of Meths .

The following parameter is to be passed to the method as a copy (Default). „byVal“ is therefore obsolete, because parameters are passed as a copy by default. Copy meaning the the source variable is left untouched.

The following parameter is to be passed to the method by reference. Reference meaning that a address pointer to the source object or variable is passed as a parameter and the method can modify the source variable. Expressions can't be passed to the method because they are neither objects, variables or data structures.

When using Classes, you may declare items with the same name again in or out of a Structure because they occupy separate namespaces. However, if you reference a method within a class with byRef, the compiler will not be able to distinguish the name structure of the object and will report a collision. In such a case use the Structur declaration of a referenced structure in the main program only.

Example 1:

' Main program
dim myvalue as integer
dim s as string
Display("My Number: ",33) ' Call Subroutine
' Alternative call
Display = 12345
s = "Different Number: "
call Display(s,myvalue)
do
loop
 
' Subroutine
procedure Display(text as string, a as byte)
  dim x as integer  ' local variable
  x=a*100
  print text+str(x)
endproc

Example 1: Variables

dim a as byte
a=23
test(a)
print "a = ";str(a)   ' Output: a = 42
do
loop
procedure test(byRef c as byte)
  print "c = ";str(c)  ' Output: c = 23
  c = 42
endproc

Example 2: Object Structure

struct point
  byte x
  byte y
endstruct
dim p as point
p.x=23
test(p)
print "p.x = ";str(p.x)   ' Output: p.x = 42
do
loop
 
procedure test(byRef c as point)
  print "c.x = ";str(c.x)  ' Output: c.x = 23
  c.x = 42
endproc

Beispiel 3: Constant Object

test(text)      ' Output: c.PString(0) = "hallo"
test("ballo")   ' Output: c.PString(0) = "ballo"
do
loop
 
procedure test(byRef c as data)
  print "c.PString(0) = ";34;c.PString(0);34
endproc
 
data text
  .db 5,"hallo"
enddata

Example 4: Memory Object

dim a(127),i as byte
for i=0 to a.Ubound
  a(i)=i
next
test(a())
do
loop
 
' Direct access to external array
procedure test(byRef c as sram)
  dim i as byte
  for i=0 to 63
    print str(c.ByteValue(i))
  next
endproc