I have been trying to understand Maple's evaluation rules for arguments or parameters as they are passed through procedures, but I am getting confused. Here is an example:

p1 := proc( y )  print( y, 'y', eval(y,1), eval(y,2) ) :  p2( y ) :  end proc :
p2 := proc( z )  print( z, 'z', eval(z,1), eval(z,2) ) :  end proc :

x := ''''5'''' :
print( x, 'x', eval(x,1), eval(x,2) ) :

p1( x ) :