Re: [Gretl-devel] A short wish list
On Mon, 22 Apr 2013, Sven Schreiber wrote:
Of course ideally gretl should give users what they need; if there is
a
feature request the user cannot automatically be expected to implement
it herself (that would somehow defeat the purpose of the software, at
least to some extent). But there is the traditional problem of scarcity
of resources. Having said this, gretl's language hansl is quite
intuitive and easy to learn, so chances are it is not so difficult to
write a function if you (or whoever) knows the statistical theory behind
the feature.
Everybody here on the list is willing to help to then integrate this
function somehow into the interface, if the feature is really considered
essential (see below).
I totally agree with Sven. Let me add just one thing, which is probably
something not everybody is fully aware of: up to some time ago (say, 2-3
years) if you wanted a certain statistical method to be part of the
standard interface of gretl, you had to code it in C and have it inserted
into the "official" codebase by Allin or myself. Conversely, any code you
wrote in Hansl had to be loaded explicity by the user at runtime through
the "Function files" mechanism or more basic ways, such as the 'include'
command in a script.
This distinction is now blurring: consider add-ons, for example. The code
for the 'GARCH variants' and the 'Structural VAR' entries you find under
the "Model > Time Series" menu are written entirely in hansl; the same
goes for the 'Panel IV model' you find under "Model > Panel". These
are
official addons, were developed (primarily) by Allin and myself and the
administrative process of integrating these into the GUI client still
requires the developer's intervention.
An even more 'democratic' way to integrate your home-made hansl code into
the GUI interface is being worked on as we speak: although we haven't
advertised it fully yet, it's altready perfectly possible to customise
your gretl client by adding your own procedure to the menus (provided it's
under the form of a working function package, which needs to be written in
hansl). As an example, the present function package for the
Phillips-Perron unit root test gives you the possibility of adding the
test to the "Variable > Unit root tests" menu.
I admit the documentation on this possibility is still severely lacking,
as this feature is still somewhat experimental. However, we intend to
polish it and document it fully in the future, since we believe that most
of the future enhancements and additions to gretl will happen through this
channel, especially as hansl becomes a more and more stable, robust and
efficient scripting language.
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Riccardo (Jack) Lucchetti
Dipartimento di Scienze Economiche e Sociali (DiSES)
Università Politecnica delle Marche
(formerly known as Università di Ancona)
r.lucchetti(a)univpm.it
http://www2.econ.univpm.it/servizi/hpp/lucchetti
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