This document describes how to use the SNOBOL4 language
 on the IBM Personal Computer and includes a reference summary for the
 SNOBOL4 language. Familiarity with the SNOBOL4 language is
 assumed.
 This manual does not attempt to teach SNOBOL4. It is only a
 reference to the language features and a guide for
 its use on the IBM Personal Computer.
 The authoritative manual for the SNOBOL4 language is entitled
 "The SNOBOL4 Programming Language, Second Edition,"
 by R. E. Griswold, J. F. Poage and I. P. Polonsky,
 published by Prentice-Hall 1971.
 This book is out of print, however.  Prentice Hall destroyed the remaining
 copies without notice.
 Ownership of the copyright for the book is quite complicated and it is unclear whether
 anyone else can arrange to publish it again.
 We have heard rumors that an Acrobat version might become available at some
 time in the future.
 We actually have a small number of copies left.
 The SNOBOL4 language is primarily a string processing language,
 yet has all of the needed constructs to write complex programs for
 other applications.
 Some of the most powerful features of the language include
 string pattern matching, tables (which are really associative
 arrays) and
 programmer defined data types.
 What makes programming in SNOBOL4 better is that these many
 powerful features are built into the language, including automatic garbage collection, and one does
 not have to find or write some separate software package
 to do these things.
 Thus, SNOBOL4 programs tend to require fewer statements than
 programs written in other languages.
 The full SNOBOL4 language has been implemented except for
 a few operating system related
 items.
 The LOAD and UNLOAD functions are not supported. In other systems
 they dynamically load subroutines from libraries and can then be
 called from SNOBOL4 programs.
 Actually, there is primitive LOAD and UNLOAD support, but it requires
 the use of assembly language and an in-depth understanding of how
 the interpreter is implemented.  Its use is discouraged at this time
 because the architecture of the interface is being changed.
 A few extra features have been added which are not part of the vanilla
 SNOBOL4 specification.  These include a few pattern elements such as
 MAXARB, built-in functions such as SORT, and several string padding
 functions.
 This SNOBOL4 implementation for the IBM Personal Computer
 was derived from the original SNOBOL4 Implementation Language
 (SIL) implementation by
 Prof. Ralph E. Griswold, while at Bell Telephone Laboratories.
 Details about SIL and the entire SNOBOL4 implementation
 are available in the book
 "The Macro Implementation of SNOBOL4" by Ralph E. Griswold,
 1972, W. H. Freeman and Company, also out of print.
 The Minnesota SNOBOL4 Interpreter
 runs source programs that you have written in the
 SNOBOL4 programming language.
 The SNOBOL4 interpreter runs your programs under the IBM Disk
 Operating System (IBM DOS) or an equivalent such as MS DOS, OS/2, Windows 95 and others.
 At least 256K of memory is recommended.
 If you wish to use any floating point operations, you also
 need a Math Co-processor (x87) or a 486DX system or higher. Without
 the Co-processor, an attempt to use a floating point operation
 will cause the SNOBOL4 interpreter to terminate with an error
 indicating that the operation is not defined.
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