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13.9 Auto-declare Input and Output

Standard (ISO/IEC 7185) Pascal specifies that whenever the required identifiers input and output are referenced in a program, they must appear as program parameters. When the auto-declare input and output extension is enabled, Irie Pascal does not require that input and output appear as program parameters.

For example the following program:

  program hello;
  begin
     writeln('Hello!!')
  end.

is equivalent to

  program hello(output);
  begin
     writeln('Hello!!')
  end.

The first program is not valid in Standard Pascal because the required identifier output is indirectly referenced by the use of the writeln procedure without specifying a file variable, but output does not appear as a program parameter.

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