Re: Lines and last lines.

[Alan Watson <alan@oldp.astro.wisc.edu>]

Several points.

Yes, I should have said that the undefined semantics of a final line
without a newline went somewhat against sam's philosophy that files
are arbitrary streams of TEXT.

The default for x is more subtle that I at first supposed, and is
useful not just when the final line of the FILE is not terminated by a
newline, but also when the final line of the RANGE is a partial line.

As to the behaviour of "x /RE/", clearly I misread the somewhat
contradictory documentation.  The sam paper states on page 6 that
"blanks in these examples are to improve readability; sam neither
requires nor interprets them."  The sam tutorial states on page 11 "if
x is followed immediately by a space, the pattern .*\n is assumed."
The man page states on page 5 that "if the regular expression and its
slashes are omitted /*.\n/ is assumed."  Is putting a space between
the x and the RE really an omission of the RE?  Apparently it is.

I don't like white-space to have sematic content (other than to serve
as a separator and terminator).  While I like the default for

	x ...

I think I might have prefered

	x /RE/...

to be equivalent to

	x/RE/...

but I guess one might argue that the difference is needed to
disambiguate

	x/RE/ ...

and
	x /RE/...

although the latter could have been written without ambiguity as

	x {
	/RE/...
	}

Can anyone think of a situation where one might want to use "x /RE/..."?

Many a time I too have blessed emacs for allowing me to edit binary
files.  Howevere, all is not lost with sam, due to it's superbly
flexible shell escapes.  All one needs a filter which takes a binary
file and writes out octal, and vice verse; one then uses ",<" and ",>"
to read an write binary, whilst editing the octal representation.

Alan.