Re: RFC: major change to argument processing.

[Marius Vollmer]

Dirk Herrmann <address@hidden> writes:

> Is it really worth the effort, to write a dedicated parser for the
> #! ... !# stuff [...]

I think so, yes.  The effort is not really that large (I think Rob has
already written it).

> if its application can be expected to be rarely used and if the
> complicatedness is then only for making people use backslashes and
> double quote characters more comfortably?

The main purpose is to allow whitespace in meta-arguments.  Using
`read' would be a clever hack to achieve this, but `read' does so much
more.  It is doing too much for his application, in my view.

> Compared to using (read), and checking the result to be a string,
> this seems simply to be overkill for me.

Using (read) and checking for the result to be string does not what we
want, however.


Ahem.  (Putting on the maintainer hat. ;) The decision is to extent
the existing meta-argument parser to also handle a shell-like quoting
syntax.

More specifically:

    A backlash removes any special meaning from the next char.  The
    backslash is discarded.

    Arguments are separated by whitespace.

    A single quote removes the special meanings from all chars except
    the single quote upto the next single quote.  The two single
    quotes involved are discarded.

    A double quote removes any special meaning from all chars expcept
    the backslash and the double quote upto the next double quote that
    has its special meaning.  The two double quotes are discarded.

That is, this

    "'"'"'"'"

forms a single argument, namely <'"'>.