REXXTACY USER MANUAL

Copyright 1991  Ruddock and Associates, Inc.





1. Introduction

1.1 REXXTACY - The REXX to C translator



REXXTACY is a package which will allow you to convert a REXX
program into an OS/2 executable. It does this by first
translating the REXX source into C code , invoking the Microsoft
C compiler, and linking the resulting object file with the
REXXTACY runtime library.

The process of converting the REXX program to C code consists of
invoking two programs - REXXCSYM and REXXCGEN. REXXCSYM is a
symbol semantics analyzer.
By examining how REXX variables are used in a program, it is
possible to emit highly optimized C code. The compiled C code
may run hundreds of times faster than the original REXX
program. REXXCSYM writes a temporary file to disk with it's
analysis. It may also generate reports for the more advanced
user to examine. Once this has been done, REXXCGEN may be
invoked. REXXCGEN reads REXXCSYM's analysis and generates C
source using the original REXX source and REXXCSYM's analysis.
This C source is ready to compile with the Microsoft C
compiler.


1.2 Using this manual

The organization of this manual has been loosly based on IBM's
OS/2 REXX reference manual. Most sections of that manual have
corresponding sections in this document. This will make it
easier for the user who wishes to find any implementation
differences between particular commands or control structures.

Since there are only a small number of differences or omissions
from REXX in REXXTACY, the manual will seem rather sparse at
points. Please be aware that this manual is not intended to be
a REXX reference manual - but rather a description of the
REXXTACY implementation.


1.3 Using REXXTACY

Both REXXCSYM and REXXCGEN have a number of options. Run
"REXXCYSM -?" and "REXXCGEN -?" for online help.

REXXCSYM's other options include:
        -o file         Write a report of REXXCSYM's findings to
                                the specified file.
        -v              Verbose analysis
        -p              Debug parser (this may only be useful to
the developer s
                        of REXXTACY)

REXXCGEN's other options include:
        -c              Compile to C only. Do not invoke the C
compiler.
        -p              Debug parser
        -P              Use protected mode library names (ending
in "P")
        -o              Compile C code with maximum optimization
        -d              Compile C code with CodeView debugging
information

If you have the TEMP or TMP environment variables set, then
REXXCSYM and REXXCGEN will use that directory to write and read
the temporary symbol file (which ends in ".tmp").

A batch file is provided (REXXTACY.CMD) which will, when invoked
with the name of a REXX program, translate and compile in one
step.

Many errors in a REXX program will be caught at compile time by
REXXTACY. However, REXXTACY provides extensive runtime error
checks. A compiled REXX program processing faulty data will emit
descriptive error messages - with lin e
numbers that refer back to the original REXX code.


2 General Concepts

2.1 Structure and General Syntax

REXXTACY input can be structured exactly like REXX input. It
supports implicit and explicit end of statement markers,
statement continuation markers and C style comments. However,
hexadecimal and binary strings are not supported at this time.


2.2 Expressions and Operators

All of REXX's logical, arithmentic and comparison expressions
and operators ar e
supported by REXXTACY - including string abuttals and operator
precedence orders.


2.3 Clauses and Instructions

REXXTACY supports all five REXX clause types:

        1. NULL Clauses
        2. Labels
        3. Assignments
        4. Keyword Instructions
        5. Commands


2.4 Assignments and Symbols

Constant symbols, simple symbols, compound symbols and stems are
all supported by REXXTACY. Assignments to these symbol types
operate exactly as they do
in REXX.


2.5 Commands to External Environments

The only command processing environment that REXXTACY
currently supports is CMD. Commands to this environment may be
issued exactly as they are in REXX.


3. Keyword Instructions

3.1 ADDRESS

Not implemented. All commands are routed to the OS/2
command shell, CMD.


3.2 ARG

Implementation identical to that of REXX.


3.3 CALL

Implementation identical to that of REXX, with the
omission of:
        - CALL ON
        - CALL OFF


3.4 DO

Implementation identical to that of  REXX.


3.5 DROP

Not implemented.


3.6 EXIT

Implementation identical to that of REXX.


3.7 IF

Implementation identical to that of REXX.


3.8 INTERPRET

Not implemented.


3.9 ITERATE

Not implemented.


3.10 LEAVE

Not implemented.


3.11 NOP

Implementation identical to that of REXX.


3.12 NUMERIC

Not implemented.


3.13 OPTIONS

Not implemented.


3.14 PARSE

Implementation identical to that of REXX with the exception
of the following omissions:
        - PARSE SOURCE
        - PARSE VERSION


3.15 PROCEDURE

Implementation identical to that of REXX.


3.16 PULL

Implementation identical to that of REXX.


3.17 PUSH

Not implemented.


3.18 QUEUE

Not implemented.


3.19 RETURN

Implementation identical to that of REXX.


3.20 SAY

Implementation identical to that of REXX.


3.21 SELECT

Implementation identical to that of REXX.


3.22 SIGNAL

Not implemented.


3.23 TRACE

Not implemented.


4. Functions

Function calls in REXXTACY operate exactly as they do in
REXX. Built in functions that are supported in REXXTACY
include:

        - LENGTH
        - LINEIN (No support for device names, line or count
                         parameters)
        - LINES (No support for device names)
        - RxFuncAdd
        - RxFuncDrop