A General Business-Oriented Language Based on Decision Expressions*

The structure of a digital compute programming
language which covers a wide class of business 
and file processing applications is presented.  Such
a structure, based on identifying and incorporating 
into a compiler the aspects common to all processes
of such class, permits writing extremely compact 
programs, even for comparatively complex applications,
in terms of tables of control expressions which 
express only information characteristic of the particular
application.  Furthermore,local changes of 
a process (e.g. changes affecting only one of the output
files involved) can be effected by local modifications 
in the program (e.g. modification of only one entry of the
tables).  This structure also allows for inexpensive 
preparation of loading-speed compilers which translate the
source programs into efficient machine codes. 
 The approach adopted here departs from conventional mechanical
language design philosophies.  It stresses 
the structural analysis of the class of processes to be represented
in the languages, as opposed to emphasizing 
formal (i.e., contents-independent) syntactical definitions.
 It relies exclusively on nonprocedural 
representation of process as sets (tables) of relations
between data and results (there are no control 
statements such as GO TO, etc.), instead of using procedure
descriptions (which are one-to-one translations 
of flowcharts).  Here an invariant pattern of procedure
is identified as characteristic of the class 
of all batch file processes.  This new philosophy has
the potential to overcome well-known deficiencies 
of other business-oriented languages and fully meets
the requirements set by CODASYL for such languages, 
including machine-independence.

CACM February, 1964

Lombardi, L. A.

CA640208 JB March 10, 1978  4:08 AM

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