NESC9983 PRAXIS.

1. NAME OR DESIGNATION OF PROGRAM:  PRAXIS.

3. DESCRIPTION OF PROGRAM OR FUNCTION

PRAXIS is a systems implementation programming language designed especially for control  and communications programming. It is a modern, strongly-typed, block-structured language similar to PASCAL but with extentions and  features particular to control systems applications. The software consists of three PRAXIS compilers and three associated support utilities - the PRAXIS RMS-11 Interface, a set of procedures, functions, and type declarations which allow PRAXIS programs to interface to the RMS-11 Input/Output system under VAX/VMS and the RSX-11M systems; TEXTIO, character I/O software for terminal and line-printer text operations; and UNPASCAL, a program which translates simple PASCAL programs into PRAXIS. The compilers included are: a VAX/VMS version which generates VAX code, a VAX/VMS  version which generates PDP11 codes, and a PDP11/RSX-11M version which generates PDP11 code. NESC Edition B of PRAXIS is designated as Version 7.3 by the contributors. The PDP11 compiler is not supported and has not been changed since February 1982.

4. METHOD OF SOLUTION

The PRAXIS compilers use LALR parsing technique to generate an intermediate machine-independent code. This is then processed using templates for the target computer to generate actual machine instructions.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM:

6. TYPICAL RUNNING TIME:

7. UNUSUAL FEATURES OF THE PROGRAM:

8. RELATED AND AUXILIARY PROGRAMS:

10. REFERENCES

- Frederick W. Holloway, Anthony J. DeGroot, Timothy A. Sherman, and   James M. Duffy,
  PRAXIS Language Environment Distribution Package Description,
  UCID-30196 Rev. 1, January 18, 1985.
- Frederick W. Holloway, Antony J. DeGroot, and Timothy A. Sherman,
  PRAXIS Releases Notes Version 7.2,
  UCID-20332, January 18, 1985.
- Frederick W. Holloway and Anthony J. DeGroot,
  PRAXIS Release Notes Version 7.3,
  UCID-20426, May 3, 1985.

- Edition B of PRAXIS
  NESC Note 85-86  (September 6, 1985)
- A. Evans Jr.:
PRAXIS Compiler Internals.  UCRL-15335  (January 1981)
- A. Evans Jr. and R.E. Shapiro:
PRAXIS Input/Output Interface.  UCRL-15336  (January 1981)
- J.R. Greenwood, A. Evans Jr., C.R. Morgan and M.C. Zarnstorff:
An Introduction to PRAXIS.  UCRL-52957 Rev. 1  (December 1980)
- J.R. Greenwood, W.I. Nowiki, A. Evans Jr., C.R. Morgan and M.C. Zarnstorff:
Programming in PRAXIS. A Detailed Introduction and Tutorial for
the PRAXIS Language.  UCID-18995  (April 1981)
- A.C. Evans Jr., C.R. Morgan, J.R. Greenwood, M.C. Zarnstorff,
G.J. Williams, E.A. Killian and J.H. Walker:
PRAXIS Language: Reference Manual.  UCRL-15331  (January 1981)

11. MACHINE REQUIREMENTS:

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

The PRAXIS compilers are written in the PRAXIS language and can run on any VAX; only PDP11s equipped with the FPU flowing-point processor are supported for code generation. Small assembly language modules interfaces each compiler to the machine's operating environment.

15. NAME AND ESTABLISHMENT OF AUTHORS

        F.W. Holloway
        Lawrence Livermore National Laboratory
        P.O. Box 808
        Livermore, California 94550, U. S. A.

prog. note               NESCNote 85-86  (September 6, 1985)        NOTPT