Jay,

Here are my thoughts on the subject of spaces left by non-existent  tokens 
in alias script expansions.  

Please excuse the fact that the names which I use for elements of the 
command line and alias script are not the same as those which you very 
nicely set forth in the ARUNZ09N.DOC file, however I wish to set forth a 
concept which depends on a slightly different nomenclature.  I think my 
meanings will be obvious.

First, let me make a couple of definitions.  

By a "string" I mean a set of characters defined by naming each element of 
the set.  Thus the statement $1 = cat means that the string named $1 is a 
set of the characters c-a-t.  A null string, in this case, is the same as 
a non-existent string.  

By a "field", I mean a >delimited< field which exists in a relationship to 
other fields.  A field consists of a string and a >field delimiter< which 
separates it from other fields.  A null field is NOT the same as a 
non-existent field.  The former consists of a field containing a null 
string, while the latter has no existence by virtue of the fact that it 
has no delimiter.  A command line and an alias script both consist of a 
set of delimited fields, the delimiter being a space or a tab.

It seems to me that what we have at present with ARUNZ (and other similar 
command line expanders) is a situation where one syntax is used to define 
two different kinds of parameters, and perhaps we need a syntax for each 
kind.  We may call one a "string substitution parameter" and the other a 
"field substitution parameter".  Currently, $n functions in ARUNZ strictly 
as a string substitution paramter.  If the command line field n contains 
the string xxxx then $n in the alias script will be so expanded.  If the 
field n does not exist in the command line, then a null string will be 
substituted in place of $n.  This is fine for such expansions as 
"FOO$1.COM" where FOO.COM is, for instance, the current version and 
previous versions have numbers which may be substituted as indicated.  
This is srictly a string substitution operation.  On the other hand, when 
we use $n to indicate the contents of a >field< in an alias script, as in 
FOO $1 $2, we are using it as a field substitution parameter.  Since we 
are substituting one field for another, this works fine unless a command 
line field is non-existent.  If this is the case, the corresponding field 
in the expanded alias script must also not exist.  Using a string 
substitution parameter for the job will simply produce a null field - not 
the same.

I would suggest that you develope ARUNZ to differentiate these two kinds 
of parameters - perhaps %n or $%n for string substitution and $n for field 
substitution, or some such.  Let me know what you think.


Best,



Lindsay Haisley