Tips: Declaring symbolic variables

[compsystems]

PHP Code:

#cas
fa(x):=
BEGIN
  local y; 
  return x*y; // "Unitialized local variable y"
END:;
#end 


fa(z) returns "Unitialized local variable y"

PHP Code:

#cas
fb(x):=
BEGIN
  local y;  purge(y) //  purge = does not contain any object == y as symvar
  return x*y; 
END:;
#end 


fb(z) returns y*z

PHP Code:

#cas
fc(x):=
BEGIN
  local y;  assume(y,symbol); // y as symvar
  return x*y; 
END:;
#end 


fc(z) returns y*z

PHP Code:

#cas
fd(x):=
BEGIN
  local y;  y=assume[expression]; // y as symvar
  return x*y; 
END:;
#end 


fd(z) returns y*z