hi again,

thanks for clarifying, i was confused by to-string/labelfn args.

i came up with something based on what you suggested. with this the code in my pkg works fine, and the hierarchy.el tests all pass.

to fix the tests for 'hierarchy-print', i found i had to also remove 'insert' inside the lambda that is the LABELFN arg for 'hierarchy-labelfn-indent', as insert returns nil and we need to return a string. hierarchy-print-line how handles 'insert'. i'm unsure about whether the let binding of to-string in -print is needed, and whether it should be the same as the let binding of labelfn in -print-line.

perhaps there is some other code it run it against also?

a patch is attached, formatted with magit from a magit diff. is that applicable, or is a different format required?

kind regards,
m


On 7/30/23 08:16, Damien Cassou wrote:
> Hi,
> 
> mousebot <mousebot@riseup.net> writes:
>> My initial query was also a way of asking if there is any (other) way
>> in hierarchy.el of printing while respecting indentation.
> 
> I think `hierarchy-print' is what you need. As you can see, the
> implementation is very short so you can also copy/paste/adapt the code
> of the function to your needs.
> 
> 
>> I'm unsure as to how to refactor hierarchy-print, as I don't
>> understand what you think it ought to do differently once
>> hierarchy-print-line is added.
> 
> The goal is to have hierarchy-print keep its current behavior but
> leverage `hierarchy-print-line' for its implementation. I have something
> like this in mind (not tested):
> 
> (defun hierarchy-print (hierarchy &optional to-string)
>    "Insert HIERARCHY in current buffer as plain text.
> 
> Use TO-STRING to convert each element to a string.  TO-STRING is
> a function taking an item of HIERARCHY as input and returning a
> string.  If nil, TO-STRING defaults to a call to `format' with \"%s\"."
>    (hierarchy-print-line
>      hierarchy
>      (hierarchy-labelfn-indent
>        (lambda (item _) (insert (funcall to-string item) "\n")))))
> 
>> I also wonder if it's perhaps a little confusing to have an arg
>> 'to-string' that is now likely to be a call to
>> `hierarchy-labelfn-indent`, whereas in `hierarchy-print` `to-string`
>> is a function handed to hierarchy-labelfn-indent as an argument.
> 
> 
> hierarchy has a notion of "labeling function" (parameters of this type
> are called LABELFN). A labeling function is one that takes an item
> object and an indentation level number as arguments and returns a
> string. The `hierarchy-labelfn-indent' function takes a "labeling
> function" as argument and returns another one.
> 
> The function that `hierarchy-print' takes as parameter is called
> TO-STRING instead of LABELFN because it only accepts an item object as
> argument.
> 
> 
>> In that case, perhaps -print-line should have the same call to
>> `hierarchy-labelfn-indent` in its body, so that the to-string arg is
>> of a similar form to -print?
> 
> 
> I disagree. In `hierarchy-print-line', the second parameter should be
> named LABELFN instead of TO-STRING (sorry for not saying that
> earlier). The docstring should say that the function is not responsible
> for indentation and that the user is free to call
> `hierarchy-labelfn-indent' or `hierarchy-print' if s/he cares about
> indentation.
> 
> 
>> Finally, is there anything wrong with simply making the indent arg in
>> the lambda in my original suggestion '&optional'?
>>
>> i.e.
>>
>> (defun hierarchy-print (hierarchy &optional to-string indent-string)
>>     (let ((to-string (or to-string (lambda (item) (format "%s" item)))))
>>       (hierarchy-map
>>        (hierarchy-labelfn-indent (lambda (item &optional indent)
>>                                    (insert (funcall to-string item indent) "\n"))
>>                                  indent-string)
>>        hierarchy)))
> 
> The problem is not this lambda as `hierarchy-labelfn-indent' will always
> call it with 2 arguments anyway. The problem is with the TO-STRING
> parameter which used to be called with 1 argument but now requires
> 2. For example, the code below works before the change you suggest but
> triggers an error after:
> 
>    (hierarchy-print hierarchy (lambda (item) (format "-%s-")))
> 
> This is because the lambda here will now be called with 2 arguments but
> it only declares 1 parameter.
> 
> To go in the direction you suggest, we could use `func-arity' on
> TO-STRING to detect how many arguments we have to pass and then call it
> with either both ITEM and INDENT or only with ITEM.
> 
>> Maybe sending 'nil' as an argument to funcall is bad news?
> 
> 
> it's not the problem
> 
> 
>> I don't really understand why the -print function shouldn't take an
>> indent-string argument, but it's your pkg not mine.
> 
> 
> this is not the problem either. The problem is passing this argument to
> TO-STRING. I hope the above would have make this clearer.
> 

-- 
some writing: https://anarchive.mooo.com
an internets: https://pleasantlybabykid.tumblr.com/
.
xmpp: mousebot@ghost.noho.st
.
gpg pub key: 0x582C8EAF0B0D77C9
fingerprint: DA24 B943 36EF C491 E22F A70B 582C 8EAF 0B0D 77C9