Why does a column's name need to start with a letter? Changed source with no perceivable side-effects

Why does a column's name need to start with a letter? Changed source with no perceivable side-effects

[Frozenlock]

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Greetings,

First and foremost, I must say I'm a new Org-mode user... as well as a new
emacs user... and have only limited experience with lisp.

I'm using a table in org-mode as a database, from which I retrieve
information as needed from other tables.
This database stores multiples components with names starting by numbers and
with the character "-" in them. For example: "10K-AN-D8".
I want to be able to refer to its column with $10K-AN-D8. Yet, this is
impossible at the moment.

I've looked in org-table.el and found, at line 2038:

(if (string-match "^[a-zA-Z][a-zA-Z0-9]*$" name)

which, once replaced by this:

(if (string-match "^[-_a-zA-Z0-9]*$" name)

Provides me with the ability to name (and refer) columns in any way I want.

However, I'm reluctant to use this feature; surely there was a reason for
this limitation.
Could someone point it out for me?

If there's no reason not to name columns as we want, perhaps it could be
modified in future versions?

Thank you very much in advance!

Christian

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Re: Why does a column's name need to start with a letter? Changed source with no perceivable side-effects

[Carsten Dominik]

Hi Christian,

On 5.3.2011, at 04:35, Frozenlock wrote:

> Greetings, 
> 
> First and foremost, I must say I'm a new Org-mode user... as well as a new emacs user... and have only limited experience with lisp. 
> 
> I'm using a table in org-mode as a database, from which I retrieve information as needed from other tables. 
> This database stores multiples components with names starting by numbers and with the character "-" in them. For example: "10K-AN-D8".
> I want to be able to refer to its column with $10K-AN-D8. Yet, this is impossible at the moment. 
> 
> I've looked in org-table.el and found, at line 2038:
> 
> (if (string-match "^[a-zA-Z][a-zA-Z0-9]*$" name)
> 
> which, once replaced by this:
> 
> (if (string-match "^[-_a-zA-Z0-9]*$" name)
> 
> Provides me with the ability to name (and refer) columns in any way I want. 
> 
> However, I'm reluctant to use this feature; surely there was a reason for this limitation.
> Could someone point it out for me?

This is limitation is present to disambiguate formulas.
In you example $10K-AN-D8, D8 is already a field reference,
so Org does not know if you mean $10K-AN - @8$4.
Furthermore, you could easily arrive at variables like
$10-AN-D8, and then what should the $10 mean?

Of cause one could disambiguate heuristically by checking
which names have been defined.  In fact, name replacement
happens first, and this is why your patch appears to
work.  But the side effect would be that introducing
new names could change the interpretation of an
existing equation.  All this is unstable and
unpredictable.

Hope this makes it clear.

- Carsten

Re: Re: [O] Why does a column's name need to start with a letter? Changed source with no perceivable

[frozenlock]

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Yes, it's very well explained, thank you.
I'll try to encode my names by removing any "-" and by adding a dummy  
letter at the beginning.

Is there another way of doing simple database in org-mode? By putting a  
component's name in a cell, I would like if the other columns could fill  
them-self with the component's characteristics.

(My apologies for the double e-mail, the first one wasn't sent to the  
mailing list)


On , Carsten Dominik <carsten.dominik@gmail.com> wrote:
> Hi Christian,



> On 5.3.2011, at 04:35, Frozenlock wrote:



> > Greetings,

> >

> > First and foremost, I must say I'ma new Org-mode user... as well as a  
> new emacs user... and have only limited experience with lisp.

> >

> > I'm using a table in org-mode as a database, from which I retrieve  
> information as needed from other tables.

> > This database stores multiples components with names starting by  
> numbers and with the character "-" in them. For example: "10K-AN-D8".

> > I want to be able to refer to its column with $10K-AN-D8. Yet, this is  
> impossible at the moment.

> >

> > I've looked in org-table.el and found, at line 2038:

> >

> > (if (string-match "^[a-zA-Z][a-zA-Z0-9]*$" name)

> >

> > which, once replaced by this:

> >

> > (if (string-match "^[-_a-zA-Z0-9]*$" name)

> >

> > Provides me with the ability to name (and refer) columns in any way I  
> want.

> >

> > However, I'm reluctant to use this feature; surely there was a reason  
> for this limitation.

> > Could someone point it out for me?



> This is limitation is present to disambiguate formulas.

> In you example $10K-AN-D8, D8 is already a field reference,

> so Org does not know if you mean $10K-AN - @8$4.

> Furthermore, you could easily arrive at variables like

> $10-AN-D8, and then what should the $10 mean?



> Of cause one could disambiguate heuristically by checking

> which names have been defined. In fact, name replacement

> happens first, and this is why your patch appears to

> work. But the side effect would be that introducing

> new names could change the interpretation of an

> existing equation. All this is unstable and

> unpredictable.



> Hope this makes it clear.



> - Carsten

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