[m-rev.] for review: change list constructor from `./2' to `[|]/2'

[Fergus Henderson]

On 23-Sep-2001, Simon Taylor <stayl at cs.mu.OZ.AU> wrote:
> Change the list constructor from `./2' to `[|]/2'. `./2' will
> eventually become the module qualification operator.

Ah, great.  Thanks.

Are there any bootstrapping issues with this change?

> +++ NEWS	2001/09/23 03:44:04
> @@ -22,6 +22,11 @@
>    Reference Manual.
>  
>  Changes to the Mercury standard library:
> +* The constructor for lists is now called '[|]' rather than '.'.
> +  `./2' will eventually become the module qualification operator.
> +  This change only affects programs which use `./2' explicitly.
> +  Programs which only use the `[H | T]' syntax will be unaffected.

This is a change to the language rather than to the standard library.

> Index: doc/reference_manual.texi
> ===================================================================
> RCS file: /home/mercury1/repository/mercury/doc/reference_manual.texi,v
> retrieving revision 1.215
> diff -u -u -r1.215 reference_manual.texi
> --- doc/reference_manual.texi	2001/08/17 03:52:35	1.215
> +++ doc/reference_manual.texi	2001/09/23 10:14:09
> @@ -316,25 +316,49 @@
>  introduction of infix operators by the use of grave accents (backquotes),
>  as described below,
>  and we support an extended set of builtin operators. @xref{Builtin Operators}.
> -However, the meaning of some terms in Mercury is different to that
> -in Prolog.  @xref{Data-terms}.
> +Also, the constructor for list terms in Mercury is @code{[|]/2}, not
> + at code{./2} as in Prolog.  The meaning of some terms in Mercury is
> +different to that in Prolog.  @xref{Data-terms}.

I think it would be better to split the last sentence into a new
paragraph:

	Note, however, that the meaning of some terms ...

> +The following terms are all equivalent:
> + at example
> +[1, 2, 3]
> +[1, 2 | [3]]
> +[1 | [2, 3]]
> +'[|]'(1, '[|]'(2, '[|]'(3, [])))
> + at end example

I suggest also including

	[1, 2, 3 | []]

in that list of examples.

> Index: tests/debugger/declarative/app.exp
> ===================================================================
> RCS file: /home/mercury1/repository/tests/debugger/declarative/app.exp,v
> retrieving revision 1.10
> diff -u -u -r1.10 app.exp
> --- tests/debugger/declarative/app.exp	2000/10/01 03:13:42	1.10
> +++ tests/debugger/declarative/app.exp	2001/09/23 07:34:37
> @@ -15,7 +15,10 @@
>  mdb> finish -n
>        16:      5  5 EXIT pred app:app/3-0 (det) app.m:26 (app.m:28)
>  mdb> dd
> -app([4, 5], [6, 7, 8], [4, 5, 6, 7, 8])
> +pred app
> +	[4, 5]
> +	[6, 7, 8]
> +	[4, 5, 6, 7, 8]

That change appears to be unrelated.

> +++ tests/debugger/declarative/app.exp2	2001/09/23 08:15:49
> @@ -15,7 +15,10 @@
>  mdb> finish -n
>        16:      5  5 EXIT pred app:app/3-0 (det) app.m:26 (app.m:28)
>  mdb> dd
> -app([4, 5], [6, 7, 8], [4, 5, 6, 7, 8])
> +pred app
> +	[4, 5]
> +	[6, 7, 8]
> +	[4, 5, 6, 7, 8]

Likewise.

> +++ tests/debugger/declarative/filter.exp	2001/09/23 07:34:48
> @@ -30,7 +30,10 @@
>  Valid? no
>  s2([7, 8, 9])
>  Valid? yes
> -my_append([1, 2], [7, 8, 9], [1, 2, 7, 8, 9])
> +pred my_append
> +	[1, 2]
> +	[7, 8, 9]
> +	[1, 2, 7, 8, 9]
>  Valid? yes
>  Found incorrect contour:
>  p([1, 2, 7, 8, 9])
> @@ -45,7 +48,10 @@
>  Valid? no
>  s1([1, 2, 3])
>  Valid? yes
> -my_append([1, 2, 3], [9], [1, 2, 3, 9])
> +pred my_append
> +	[1, 2, 3]
> +	[9]
> +	[1, 2, 3, 9]

Likewise for those two.

> +++ tests/debugger/declarative/filter.exp2	2001/09/23 08:17:47
> @@ -30,7 +30,10 @@
>  Valid? no
>  s2([7, 8, 9])
>  Valid? yes
> -my_append([1, 2], [7, 8, 9], [1, 2, 7, 8, 9])
> +pred my_append
> +	[1, 2]
> +	[7, 8, 9]
> +	[1, 2, 7, 8, 9]
>  Valid? yes
>  Found incorrect contour:
>  p([1, 2, 7, 8, 9])
> @@ -45,7 +48,10 @@
>  Valid? no
>  s1([1, 2, 3])
>  Valid? yes
> -my_append([1, 2, 3], [9], [1, 2, 3, 9])
> +pred my_append
> +	[1, 2, 3]
> +	[9]
> +	[1, 2, 3, 9]

Likewise.

> +++ tests/debugger/declarative/queens.exp	2001/09/23 08:19:27
> @@ -17,9 +17,15 @@
>  Call qperm([1, 2, 3, 4, 5], _)
>  No solutions.
>  Complete? no
> -qdelete(1, [1, 2, 3, 4, 5], [2, 3, 4, 5])
> +pred qdelete
> +	1
> +	[1, 2, 3, 4, 5]
> +	[2, 3, 4, 5]
>  Valid? yes
> -qdelete(2, [1, 2, 3, 4, 5], [1, 3, 4, 5])
> +pred qdelete
> +	2
> +	[1, 2, 3, 4, 5]
> +	[1, 3, 4, 5]
>  Valid? yes
>  Call qperm([1, 3, 4, 5], _)
>  No solutions.

Likewise.

Otherwise this change looks fine.

-- 
Fergus Henderson <fjh at cs.mu.oz.au>  |  "I have always known that the pursuit
The University of Melbourne         |  of excellence is a lethal habit"
WWW: <http://www.cs.mu.oz.au/~fjh>  |     -- the last words of T. S. Garp.
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