OPAL, an Open Physical Analysis Language

Paper: 210
Session: A (talk)
Speaker: Shamov, Andrei, Budker Institute of Nuclear Physics, Novosibirsk
Keywords: analysis, programming languages, software tools

OPAL, an Open Physical Analysis Language.

A.G. Shamov
Budker Institute of Nuclear Physics
630090 Lavrentiev street 11, Novosivirsk, Russian Federation


The last fifteen years of HEP showed that the PAW program
developed in CERN is an excellent tool for data analysis. A
drawback of it is the existence of the two different languages
an user has to use. Writing the KUIP macro, one is lacking of
the FORTRAN power and flexibility. Writing FORTRAN code for
COMIS, one can not employ convenient KUIP commands and has to
call of HBOOK and HPLOT routines directly.
The author attempted to invent a single language which
includes simple and convenient commands for histogram booking,
filling and plotting together with most important FORTRAN-77
operators. The best way to solve the problem was developing of
an OPEN language expandable with user-defined commands.
OPAL has extended DCL-like syntax with qualifiers and multi-
level command parameters allowing to describe almost all
FORTRAN-77 operators.
The OPAL compiler/interpreter can be linked with any
application. To introduce a language statement an user should
call the subroutine to describe the syntax and supply the
procedure performing the actions required. The user can
predefine a set of variables, arrays and functions which will be
available in interactive sessions together with dynamically
created objects.
On the base of OPAL the XBOOK interface to HBOOK, HPLOT and
HIGZ packages was developed. XBOOK uses specific approach to
histogram filling which allows to control the filling process
interactively and speeds it up.
OPAL and XBOOK are used a few years in on-line and off-line
applications for CMD-2 and KEDR experiments at BINP storage
rings. At the moment they are available under VAX/VMS only.