A GUIDE TO CONVERTING ESP PROGRAMS TO CESP PROGRAMS
ESP (Extended Self-contained Prolog) is an object-oriented logic
programming language that was developed by ICOT. ESP can run only on
a PSI that is an ESP machine. On the other hand, AI Language Research
Institute, Ltd. (AIR) extended ESP, and developed CESP (Common ESP) so
that it can be used on UNIX machines. This document shows several
general points to be noted when converting ESP programs to CESP
programs. This document is written with the aid of AIR.
CESP is not part of the ICOT Free Software, instead being available
from MITSUBISHI ELECTRIC COMPUTER SYSTEMS(TOKYO) CORP. (MTC).
CESP Ver.3.3 assumes the following environment.
Computer : SUN4 (SPARC)
Operating System : Sun OS R4.0.3, R4.1, R4.1.1 or R4.1.2
Main Memory : 16MB or more (Swap size is 64MB)
Disk Storage : 90MB or more for SUN4 (SPARC)
Editor : Interactive debugging environment installed
on GNU Emacs (preferred)
Window : Available X11R4 interface / Japanese characters
with Xmw (for X11R5) and Wnn (R4.0.2)
For further details, apply to MTC by Fax or Postal mail.
MITSUBISHI ELECTRIC COMPUTER SYSTEMS CORP.
2-nd Application Systems Develpment Dept.
Software Products Promotion Group
87-1, Kawakamicho, Totsukaku, Yokohama,
Kanagawa 244, Japan
TEL: +81-45-825-5679(Japanese Only)
2. Conversion to CESP
Many ESP programs need a PSI machine and SIMPOS (the OS of PSI). When
you convert such programs to CESP programs, one task is to rewrite the
incompatible segments such as I/O part. Some fundamental data forms
of CESP are different from those of ESP. Read the CESP Language
Manual  first. Some general points of conversion are as follows:
- (1) Built-in predicates
- (a) Built-in predicates for PSI
- You must rewrite the part of the program (e.g., built-in
predicates such as "word", "set_system_register" or "address") that
depends on the PSI hardware (e.g., register, 40bits/word).
- (b) Differences in built-in predicates of CESP and ESP
- The predicates of ESP, "heap_vector" and "stack_vector",
correspond to "impure_vector" and "pure_vector" in CESP. Read  to
learn the differences in CESP and ESP built-in predicates.
- (c) Standard operators of CESP
- Some special symbols such as "&" and "**" are used as standard
operators in CESP but not in ESP. Before you can declare "add_op" of
such operators in CESP, you must declare "remove_op" of them.
- (2) Data form
- (a) Data form of string
- Although 1 bit string data and 32 bit string data are available in
ESP, they are not available in CESP. Use "impure_vector" instead in
- (b) Range of integer
- While the range of the integer in ESP is from -2^31 to 2^31-1,
that in CESP is from -2^28 to 2^28-1.
- (c) Character code
- While the character code in ESP is JIS (Japanese Industrial
Standard; JIS X 0208-1983), that in CESP is EUC.
- (d) Comparison of different data type
- Data types are compared differently in CESP and ESP.
- (3) Interface
- (a) Window methods
- The window in CESP is different from that in ESP. In particular,
the emacs_window in CESP is different from the pmacs_window in ESP.
(You can use the "scrollbar" instead of the pmacs_window.) The macros
for the mouse in ESP (e.g., mouse#r) must be changed to the atoms in
CESP (e.g., 'mouse#r'). You can not use the extra PSI font on UNIX
- (b) File I/O methods
- The file I/O methods in CESP are a little different from those in
ESP. For example, the order of arguments in the ":create" method is
- (c) Method for library and directory etc.
- Some methods for the library and directory etc. in ESP are not in
CESP. You need to program the difference.
- (4) Others
- (a) Capacities of PSI and UNIX machine
- The UNIX machine and the ESP machine differ as follows: the
execution speed of CESP on the UNIX machine is slower than ESP on PSI,
and the UNIX machine does not have as much memory as PSI. If a class
has many clauses, you should divide the class.
- (b) Exception manipulation
- - set_mode exception_fail/exception_handler
- You can set these in CESPshell. You can choose for the
CESP system to manipulate exception as failure, or for the system to
show a manipulation menu when an exception occurs.
- - set_exception_object/2
- You can designate any class to be called when an exception
occurs. The method in CESP is different from that in ESP.
- (c) Inheritance of "as_program"
- Any class cannot inherit "as_program". It does not exist in CESP.
-  CESP Language Guide Version 3, AI Language Research Institute,