Re: port-line and port-column

[Per Bothner <bothner@cygnus.com>]

So is there a resolution?

Point of information:  I convinced Stallman that 1-origin column
numbers are more natural for (non-programmer) users, but he is
not sure whether it is better for column numbers to match
(naive) user expectations, or whether they should match the
ELisp API.

Here is my suggestion:

 - primitive: port-column [INPUT-PORT]
 - primitive: port-line [INPUT-PORT]
     Return the current column number or line number of INPUT-PORT,
     using the current input port if none is specified.
     If the number is unknown, the result is #f.  Otherwise,
     the result is a 0-origin integer - i.e. the first character
     of the first line is line 0, column 0.  (However, when you
     display a file position, for example in an error message,
     we recommand you add 1 to get 1-origin integers.  This is
     because lines and column numbers traditionally start with
     1, and that is what non-programmers will find most natural.)

We might consider as a future extension that output ports
could also support port-line and port-column.  One use for port-column
for output ports is to support the tabulate format specifier.
(The Common Lisp "tabulate" format specifier has 0-origin columns.)

	--Per Bothner
Cygnus Solutions     bothner@cygnus.com     http://www.cygnus.com/~bothner