Unix environment parsing with Mocka

Besides knowing the command line parameters, it is often required to get a notion of the unix environment variables that can be listed from a terminal with the 'set' command. But for accessing these vars from within an executable, another mechanism is required.
This project is about the reading of environment parameters from within a running executable. I wrote this flimsy program just to familiarize with the way the Unix environment variables can be accessed and dealt with.

MODULE trye;

FROM  Arguments  IMPORT  ArgTable, GetEnv;
FROM  InOut	 IMPORT	 WriteCard, WriteLn, WriteString, WriteBf;
FROM  Strings	 IMPORT	 Assign, Length;


VAR   item	 	 : CARDINAL;
      storage		 : ArgTable;
      Value		 : ARRAY [0..511] OF CHAR;


BEGIN
   GetEnv (storage);
   item := 0;
   LOOP
      IF  storage^ [item] = NIL  THEN  EXIT  END;
      Assign (Value, storage^ [item]^);
      WriteCard (item, 4);
      WriteString (' :  [');    WriteCard (Length (Value), 4);
      WriteString (']  ');      WriteString (Value);
      WriteLn;
      INC (item)
   END;
   WriteBf
END trye.

This source code is fairly similar to the program to get hold of the commandline parameters, only in this instance we don't know upfront when the table is over....
With 'GetEnv (storage)' we prime the array that contains all the environment variables. Later we access the strings one by one as in any array of characters.
The rest of the source is rather straightforward:

set up a loop-counter
enter an infinite loop
check for end of table
do some printing on the screen
write the variable
end the line
increment the index
and loop back

If all is done, we make sure every single bit is printed with the 'WriteBf' command.

Have fun with Modula-2. If you need to mail me, look in the navigator of this section.

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