Re: Add internal definitions to derived forms

[Linus Björnstam]

Hi!

Sorry about the delay, I have an updated patch somewhere, but I started working 
after 4 months paternity leave and family life's fortunes has it so that I 
haven't used a computer since the last time I wrote an email in this thread 
(this is written on a phone).

This is likely how will be in the foreseeable future, despite me having bought 
an analog keyboard to turn into some kind of music instrument :)

For what it is worth:

The body ... was taken from and-let* and the newer patch was changed to follow 
the description of let. And "lambda-like body" was changed to "let-expression 
body".

I will not have the ability to address anything nor actually send my updates 
patch for what is probably months. If anyone wants to take over I would be 
happy. For what it is worth, I have already signed a copyright assignment to 
the FSF. 

Best regards
  Linus Björnstam (manumanumanu)

On Tue, 24 Jan 2023, at 00:28, lloda wrote:
> Hi Ludovic,
>
>> On 23 Jan 2023, at 23:13, Ludovic Courtès <ludo@gnu.org> wrote:
>> 
>> Hi Daniel,
>> 
>> Chiming in late in the discussion…
>> 
>> lloda <lloda@sarc.name> skribis:
>> 
>>> From 7aea299373f7370f31c9701035260ad412763724 Mon Sep 17 00:00:00 2001
>>> From: Daniel Llorens <lloda@sarc.name>
>>> Date: Thu, 19 Jan 2023 16:23:29 +0100
>>> Subject: [PATCH 2/2] Fix documentation for forms taking lambda-like bodies
>>> 
>>> * doc/ref/api-control.texi (Conditionals): Use 'body' in the syntax
>>>  description of when, unless, cond, case.
>>> * doc/ref/api-binding.texi (Local Bindings): Normalize description of
>>>  body return values.
>>>  (Multiple values): Normalize use of 'body' and description of body
>>>  return values.
>> 
>> What about:
>> s/Fix documentation…/doc: Document multiple-value returns in let, cond, etc./
>> ?
>> 
>> (That would clarify what’s being fixed.)
>
> Ok.
>
>> 
>>> +++ b/doc/ref/api-binding.texi
>>> @@ -128,6 +128,8 @@ expressions has a few properties which are well worth 
>>> knowing.
>>> 
>>> The most basic local binding construct is @code{let}.
>>> 
>>> +@cindex body
>> 
>> That’s not a great index entry because there’s no context.  Maybe:
>> 
>>  @cindex body, of a @code{let} expression
>> 
>> ?
>
> Ok. I think the word is only used in this sense in the manual, but it 
> might too generic to be used alone.
>
>>> +with the special forms @code{when} and @code{unless}.  As an added
>>> +bonus, these forms take a @ref{Local Bindings,lambda-like body}, which can
>>> +contain @ref{Internal Definitions,internal definitions} and multiple 
>>> statements
>>> +to evaluate.
>> 
>> “Lambda-like body” is not defined; I guess it’s “lambda-like” in the
>> wrt. to local ‘define’, but it’s not “lambda-like” for the more crucial
>> aspect of defining a procedure, so I’d avoid that phrase.  WDYT?
>
> Yes, I thought lambda-like was a tad distracting, so I went with 'body' 
> alone...
>
>> Also, @ref in the middle of sentences may render poorly in Info (info
>> "(texinfo) @ref").  I’d suggest “(@pxref{Whatever})” at the end of the
>> sentence or proposition.
>
> Ok.
>
>>> Each @code{cond}-clause must look like this:
>>> 
>>> @lisp
>>> -(@var{test} @var{body} @dots{})
>>> +(@var{test} @var{body})
>> 
>> I think removing dots is incorrect here because it suggests, according
>> to the typographic conventions used in the document, that there can only
>> be a single expression.
>> 
>>> @var{key} may be any expression, and the @var{clause}s must have the form
>>> 
>>> @lisp
>>> -((@var{datum1} @dots{}) @var{body} @dots{})
>>> +((@var{datum1} @dots{}) @var{body})
>> 
>> Ditto.
>> 
>>> and the last @var{clause} may have the form
>>> 
>>> @lisp
>>> -(else @var{expr1} @var{body} @dots{})
>>> +(else @var{body})
>> 
>> Ditto.
>> 
>>> -@deffn {library syntax} receive formals expr body @dots{}
>>> +@deffn {library syntax} receive formals expr body
>> 
>> Likewise.
>
> This was actually the main thing I wanted to fix in this patch. Linus' 
> patch had ‘body ...’ but that clearly means ‘zero or more bodies’, 
> which doesn't work because there's exactly one ‘body’. I.e. ‘body’ 
> isn't an expression that is tagged ‘body’, it's, well, a ‘body’.
>
> The Scheme reports use one ‘<body>’ and no dots in all these 
> definitions. See also the definition of let in the linked section 
> ‘Local Bindings’, which again uses ‘body’ and no dots. I hoped that 
> section would count as definition of ‘body’, and the section on 
> ‘Internal Definitions’ explains precisely what can go into ‘body’, so I 
> linked to that as well. I see that isn't clear enough. Maybe ‘body’ 
> should be explicitly defined in one of these sections?
>
>> Otherwise LGTM; it’s certainly an improvement to have multiple-value
>> returns properly documented!
>> 
>> Thanks,
>> Ludo’.