[MLton] the syntax of MLBs

[Stephen Weeks]

The main reason I brought up the scripting stuff now, even though it's
not part of the upcoming release, is that it may affect the syntax of
MLBs, which are part of the release.

In thinking about MLBs, a couple of other ideas about syntax occured
to me.

1. It seems that there is no way to include a file name with a space
   in it.  This is bad.  One way to fix this would be to put filenames
   in double quotes, and use the same lexical rules as for SML
   strings.

2. I wonder if we went overboard with my goal of making a list of
   files be a valid mlb.  Would it perhaps be better or clearer if we
   had a keyword to import files.  We could use "include", "require",
   "import" (although that's not so good because of _import), or
   something else.  So, instead of  

	foo.sml
	bar.sml

  We would have

	include "foo.sml"
	include "bar.sml"

  or even

	include "foo.sml" "bar.sml"

  Maybe "open" would be a reasonable keyword as well, if we think of
  the meaning of a file as a basis and referring to the file as
  opening that basis.

3. I wonder if we should emphasize the different treatment of
   .sml files and .mlb files using different keywords.  Perhaps we
   should write

	include "foo.sml"
	open "foo.mlb"

   to emphasize that .sml files are re-elaborated at each instance,
   while .mlb files are like a basis that is opened.