[m-rev.] for review: don't allow nondefault mode functions in terms

[Zoltan Somogyi]

On Mon, 02 Nov 2015 07:22:35 +1100 (AEDT), "Zoltan Somogyi" <zoltan.somogyi at runbox.com> wrote:
> OK. I will post a proposed diff to the reference manual for review.

Here it is.




diff --git a/doc/reference_manual.texi b/doc/reference_manual.texi
index 77a8cb9..37dbe60 100644
--- a/doc/reference_manual.texi
+++ b/doc/reference_manual.texi
@@ -4500,6 +4500,15 @@ term that does not match this standard mode to somewhere where its higher-order
 inst information may be lost, such as to a polymorphic predicate where the
 argument mode is @code{in}.
 
+The Melbourne Mercury implementation currently cannot track
+all the places where higher-order inst information could be lost
+if a function is put into a term.
+To preserve safety, it therefore requires that
+functions may be put into terms only if they have the default signature,
+i.e. all their arguments have mode @code{in},
+their result has mode @code{out},
+and they have determinism @code{det}.
+
 Mercury also provides builtin @samp{inst} values for use with solver types:
 
 @example

I am committing the diff with this change to the manual.
Any review comments on the diff to the manual are best done
by editing the updated text.

Zoltan.