Text archives

The following items are in fact identical. They use the same text archive mechanism; they are just triggered by a different command archives and should help to clarify the contents from the standpoint of the user.

  MAC=name   points to the EDA Macro file
  TAR=name   archive for the TAR (text archive command)
  MAN=name   archive for the MAN command
  TEA=name                   TEACH command
  INF=name                   INFO command
  EXP=name                   EXPLAIN command
  APR=name   archive for the APROPOS command

Note also that <name> may be two things:

(1) a full file specification, i.e. pointing to a text archive

(2) a directory path

If you are typing e.g. MAN BOXPLOT, EDA checks whether name exists: if MAN= contains a file name, EDA treats the file name as an archive, i.e. attempts to extract the item <BOXP> from that archive and if it is found displays it. If MAN= contains a directory path, EDA tries to find a file named BOXP in that directory.

Text archive structure

EDA text archives have a very simple structure. They are stored in normal text files, i.e. can be created an editied using a standard ASCII editor or an wordprocessor in non-document mode.

As an example let us look at the beginning of a macro library (which has the same structure as all other text archives).

(1)   EDA$TARC &08
(2)   &DEMO     EDA demo
      &FEXIST   Demo macro: checking file existence, and tell user
      &STAIR    Show letter values as a staircase
      &SPADOUT  produit les etapes DONNE et LILEX pour SPAD
(3)   //
(4)   &DEMO
(5)   !! EDA Demo
      >    This is a short demonstration of EDA
      >    ************************************
             (many more text lines)
(4)   &FEXIST
        (macro body)

Explanations: (1) Is the text archive (TAR) header and contains the identifier 'EDA$TARC'. This identifier is mandatory.

  Cols 1-8   'EDA$TARC'   identify TAR
       9     leave blank for future extensions
       10    tag used to identify differnt text items, here & is used
             (used in the table of contents and body section);
             if ommitted EDA uses the # tag.
       11-12 lenght of item name, here item names can be up to
             8 letters, i.e. 8 letters are checked. You might want to
             set this to 4, when you want to create an archive explaining
             EDA commands.

(2) After the single-line header follows the table of contents (TOC) section, where all items in the file are listed. Note only items tagged correctly are identified as items. The explanatory text following the name of the item can be displayed with the RUN &DIR command, i.e. shows the TOC entries.

(3) The // signal terminates the TOC section. (4) signals the beginning of the item 'DEMO' which then is defined in (5); there is no limitation to the number of texts lines in an item. You should introduce as many (4) (5) sections as entries specified in the TOC section.

How to use an archive

Using this mechanism you may for instance build a library of items your users retrieve with the INFO command. You will have to do the following:

(1) Create an entry in the profile file pointing to the file where you will store the archive, e.g. INF=c:\INF\INFO.TAR. INF means that this entry is linked to the INFO command.
Create the file INFO.TAR as explained above (where we've used the macro library as an example) and store it into the c:\inf\ directory. Make sure all users have access to the file.

There is an alternative to storing information in an archive. Instead of using a text archive you could add INF=C:\INF\ to your profile. Then when you type for instant INFO PRINTING, EDA will simple look for a file called 'PRINTING' in the c:\inf\ directory. If it is found, its content will be displayed.

It is planned to supply a number of text archives with future versions of EDA.