On Thu, Jun 17, 2010 at 2:44 PM, Darren Duncan <dar...@darrenduncan.net>wrote:
>
>
> I wanted to let you know that I plan ASAP to enhance the PTMD_STD (normal)
> dialect of Muldis D to be more friendly to people who like programming
> languages
> without sigils, so further towards Python/C/SQL/etc and from Perl/etc.
>
what motivated this decision? did a lot of people make this request of you?
>
> Specifically, I'm going to make the "data sigil" ("$") lexical element
> optional,
>
typically when language elements are optional it enhances readability:
my %val = (a => 1, b => 2); # no quotes needed for 'a' and 'b'
> but still enforcing consistency such that within the scope of a single code
> file
> you must either use or not use the "data sigil" everywhere; no
> mix-and-match,
>
I dont really like this idea of trying to have two different syntaxes like
that for a single dialect, even if you can change it with a config option
such as you have showed.
> Mainly I included the "$"
> everywhere I did because *I* think it makes the code more readable, quickly
> identifying at a glance what is a variable/etc versus what isn't.
right, so since it makes it more readable, who/what suggested otherwise?
>
>
> At the bottom of the page http://muldis.com/Muldis_D.html is a "hello
> world"
> program in its original form that uses data sigils;
To me, $ implies 'var' so why not just:
$name : Text
$addr : Text
> here is the primary part of
> the same program without the $s; it is identical but no $ characters:
>
> procedure main () [
> # This is the program's main procedure. #
> write_Text_line( 'Hello!' )
> var people : Relation
> { people := Relation:{ name, addr } }
>
it seems overly verbose to have two lines for this... could you not have
done:
var people : Relation:{name, addr } }
> var name : Text
> var addr : Text
> var msg : Text
>
> write_Text_line( 'First add some info. Enter blank line when done.'
> )
> |gather_person ::= loop [
> # Gathers person info from user. #
> prompt_Text_line( &name, 'Enter a person\as name: ' )
> given name when '' leave |gather_person
> prompt_Text_line( &addr, 'Enter that person\as address: ' )
> given addr when '' leave |gather_person
> # Adds a person to our db of people. #
> assign_insertion( &people, Tuple:{ >name, >addr } )
> ]
>
> write_Text_line( 'Now search for info. Enter blank line when done.'
> )
> |lookup_person ::= loop [
> prompt_Text_line( &name, 'Enter a name to search for: ' )
> given name when '' leave |lookup_person
> {
> # Look up person by name, get their address. #
> matched_people ::= people matching Relation:{ { >name } }
>
This ">" sign confuses me (of course I havent read the spec), but I
immediately think of greater-than name without knowing more about this
language.
> msg := given r# matched_people
> when 0 then 'No person matched'
> when 1 then 'Found address for that person is: '
> ~ (t matched_people).addr
> default 'More than one person matched'
> }
> write_Text_line( msg )
> ]
>
> write_Text_line( 'Goodbye!' )
> ]
>
> A code file without sigils would have a language declaration like this:
>
> Muldis_D:"http://muldis.com":0.130.0:PTMD_STD:{
> catalog_abstraction_level => rtn_inv_alt_syn,
> op_char_repertoire => basic,
> uses_data_sigil => False
> }
>
> ... while one using sigils would say "True" instead of "False". Specifying
> that
> pragma name and value is mandatory, since there is no reasonable default
> answer.
>
> Now, I figure that this change should have almost no impact on how easy it
> is to
> parse Muldis D code, and in fact I'd probably just have to change not more
> than
> a half-dozen lines in the grammar definition to provide the option.
>
> The main downside I see of not requiring the $ is that there is more risk
> of
> conflict between language keywords and variable/etc names used as
> barewords,
> since user entities may be named anything at all; however, since all entity
> names can be delimited with double-quotes (like in SQL), users can quote
> any
> otherwise-bareword names to clarify that they are not keywords, in the
> appropriate circumstances; so `foo`, `$foo`, `"foo"`, `$"foo"` all refer to
> the
> variable/etc named "foo".
>
that spells confusion if you ask me.
