Pascal Report  199  12.5.  Page  13.  Programs  Page ( f)  implies an implementation-defined effect on the textfile f,  such that any text subsequently written to  f  will appear at the top of a  new page when  f  is printed. If  f  is not empty, and the last component  of its sequence is not an end-of -line marker, then Page  (f)  perfonns  an implicit Writeln  (f). If  the parameter list is omitted, the textfile  program parameter  Output is assumed. It is an error if  f  is undefined  or if  f  is not in generation mode.  The effect of reading a file variable to which Page was previously  applied is implementation-dependent.  A Pascal program consists of a program heading and a block.  Program  =  ProgramHeading  ";"  Block  "." .  ProgramHeading  =  "program"  Identifier  [  ProgramParameterList  1  .  ProgramParameterList  = "("  IdentifierList  ")" .  The identifier following the symbol program is the program name;  it has no further significance inside the program. Each identifier in the  program parameter list is called a program parameter, and denotes an  entity that exists outside the program and that, therefore, is called  external.  It  is  through  its  program  parameters  that  the  program  communicates with its environment.  When a program is activated, each program parameter is bound to  the external entity that it represents. For those program parameters that  are file variables, the binding is implementation-defined; for all other  program parameters, the binding is implementation-dependent.  Each program parameter, with the exception of Input and Output,  must be declared in the variable declaration part of the program's block.  In the case of  Input or Output, the occurrence of the identifier in the  program parameter list has  the  effect of implicitly declaring the  identifier  in  the  program  block  to  be  a  textfile,  and  implicitly  perfonning  a  Reset (Input)  or  Rewrite (Output)  at  the  commencement of each activation of the program. 