READ_ME

rom: rsalz@uunet.uu.net (Rich Salz)
Newsgroups: comp.sources.unix
Subject: v16i067:  Spiff, find approximate differences in files, Part01/04
Message-ID: <1182@papaya.bbn.com>
Date: 11 Nov 88 18:18:05 GMT
Approved: rsalz@uunet.UU.NET

Submitted-by: Daniel W Nachbar <daniel@wind.bellcore.com>
Posting-number: Volume 16, Issue 67
Archive-name: spiff/part01

[  This is the program Dan presented at his \fIexcellent\fP talk at
   SF Usenix.  For those who weren't there, yes, Spiff is named after
   the comic strip character in Calvin and Hobbes.  The "MGR" window
   system mentioned in the README will be appearing here shortly.  I
   repacked this submission.  --r ]

The well known program diff is inappropriate for some common tasks such as
comparing the output of floating point calculations where roundoff errors
lead diff astray and comparing program source code where some differences
in the text (such as white space and comments) have no effect on the
operation of the compiled code. A new program, named spiff, addresses
these and other similar cases by lexical parsing of the input files and
then applying a differencing algorithm to the token sequences. Spiff
ignores differences between floating point numbers that are below a user
settable tolerance.  Other features include user settable commenting and
literal string conventions and a choice of differencing algorithm. There
is also an interactive mode wherein the input texts are displayed with
differences highlighted. The user can change numeric tolerances "on the
fly" and spiff will adjust the highlighting accordingly.