# From arnold@f7.net  Sun Sep  5 12:30:53 2004

# Date: Fri, 3 Sep 2004 00:54:32 -0400 (EDT)

# From: William J Poser <wjposer@ldc.upenn.edu>

# To: arnold@skeeve.com

# Subject: gawk bug

# Message-ID: <20040903004347.W80049@lorax.ldc.upenn.edu>

# 

# Here is a revised version of my previous message, modified to describe

# the accompanying files.

# 

# IhSplit.awk should replicate every record with exactly one entry in the

# IH field, delete records lacking an IH field, and produce as many copies

# of records with two or more entries in the IH field as there are entries.

# In the latter case, the original IH field should be relabelled OIH and

# a new IH field be added at the beginning of the record.

# 

# This has worked properly for many years, since at least 1997. It worked properly with gawk 3.0.5

# and possibly later versions. Unfortunately I didn't keep track of exactly what version it

# broke on, but it was whatever came with Mandrake Linux 9.0. It continued to fail with version

# 3.1.2. However, the problem was eliminated with version 3.1.3 and remains

# eliminated in version 3.1.4.

# 

# The problem was that an apparently random subset of records would loose some

# or all of their fields. Running the script on the same input always produces

# the same output with the same errors.

# 

# The file Input is a subset of a real lexicon that produces errors using

# gawk 3.1.2. GoodOutput is the expected output. BadOutput is the erroneous

# output. A diff will show that there are actually two errors. One record

# has fields stripped as described above. Another is omitted in its entirety.

# 

# 

# Bill Poser, Linguistics, University of Pennsylvania

# http://www.ling.upenn.edu/~wjposer/ billposer@alum.mit.edu

# ----------------------------------------------------------------------------

#For each record that contains multiple items in its inverse headword (IH)

#field, generate a set of new records each containing exactly one item

#in the inverse headword field, otherwise copies of the original.

function CleanUp() #Clean up for next input record.

{

  for(i in rec) delete rec[i];

}

BEGIN {

RS = "";

FS = "\n?%"

}

{

# First, create an associative array with the tags as indices.

  for(i = 2; i <= NF; i++) { # The leading FS creates an initial empty field

       split($i, f, ":");

       rec[f[1]]=substr($i,index($i,":")+1);

  }

  if(!("IH" in rec)) next;

# Parse out the inverse headwords

     items = split(rec["IH"],ihs,"/");

# Replace the old IH field.

     sub(/%IH:/,"%OIH:",$0);

# Generate a new copy of the record for each inverse headword

       for(i = 1; i <= items; i++){

	 entries+=1;

         printf("%%IH:%s\n",ihs[i]);

         printf("%s\n\n",$0);

       }

       CleanUp();

  }