separate the command language and interactive she

[Felix Lee]

>  <command-line> ::= <command> <arg>* | "set" <var> = <arg>
>  <arg> ::= "-"<char>* | "$"<var> | <file>
>  path-complete <command> with "echo $path"
>  path-complete <file> with "pwd"
>  list-complete <var> with "variable-completion %s"

Let's see.  The syntax is naive: it doesn't do quoting of any sort, so
you can't do file completion on files with special characters in it.

How about completing filenames with variables embedded: "$HOME/$a/a".

How about history completion: expand things like "!$" and "!vi".

How about glob completion: expand things like "*" and "f*".

A more serious problem: the shell isn't the only thing that
wants/needs completion.  gdb, for example, wants to do completion.

Teaching the front-end about all this gets ugly.

The simplest way to handle completion is to have a communication
channel between the front-end and the current interactive process.
(Which immediately has two problems in Unix: What's the "current
interactive process"?  How do I talk to it?  (So how do we fix Unix?))
--
Felix Lee	flee at cs.psu.edu