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InterFilter -- process InterOpal files before they are examined by the 
	       Opal compiler's backend

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The newest Opal compiler (ocs2.3b or later) uses exclusively Interopal as
the means to pass the abstract syntax from the frontend to the backend. This
means that additional checks or changes of the abstract syntax may be added
in a modular fashion to the Opal compiler by calling Interopal filters in
between the frontend and the backend. 

The script xoc1 in the ocs/bin directory may be used to control these
filters. The ProjectDefs file in this directory has been prepared to ease
the addition of these filters. In order to change the filters used, edit the 
contents of the FILTERS variable. THE XOC1 variable may be used to add or
remove options to xoc1 script. Changing other variables should not be
necessary.

The xoc1 script will call the filters in the given order. If one of them
exits with a status != 0 the Interopal file is removed and xoc1 exits with
the same error code. Calling xoc1 --help gives a list of xoc1 options.
Note that xoc1 will pass the file name of the Interopal file to be processed 
as the first argument to the filters called. 

This directory contains to sample Interopal filters.

cases can be called with either "--upper"  or "--lower" as its second
argument and will change the names of all objects accordingly.

checkImpl aborts if an implementation contains non-implemented functions.



Klaus Didrich ---------------------------------------- 30 July 1998