"dnearineigh" source code

I need to look into the code for "dnearneigh" so that I could get an idea of
how to make weight matrices for any observation (i) based on some criteria.
But a look into the spdep pack pointed me to the "spdep.dll". Probably
written in some other languages. So I guess my question is how can I see the
actual code for this and indeed other functions.

Please see:

http://cran.r-project.org/doc/Rnews/Rnews_2006-4.pdf

pp. 43-45 for a general answer. For all CRAN packages, the source code is 
always available for current versions on the package page, and for earlier 
versions in the archives. For some packages, including spdep, R-Forge 
hosting means that the source code can also be browsed online, at:

https://r-forge.r-project.org/scm/viewvc.php/?root=spdep

However, you are almost certainly not approaching this in a sensible way, 
as the glist= argument provides complete flexbility for adding arbitrary 
general weights to an nb object - list of neighbours. You do not need 
access to dnearneigh() internals to do this. If you want to define the 
neighbours in some specific way not already provided, you need to create a 
list of integer vectors of indices in the 1:n range for n observations, 
coding no-neighbour observations with the single integer id 0, adding 
class and other attributes.

Hope this helps,

Roger

[The only answer I got by searching close to my problem is the answer by
Prof. Bivand on the "lag.listw":
http://r-sig-geo.2731867.n2.nabble.com/lag-listw-function-in-spdep-package-td2762785.html
which belongs to 2006. ]

Roger Bivand
Department of Economics, NHH Norwegian School of Economics,
Helleveien 30, N-5045 Bergen, Norway.
voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: Roger.Bivand at nhh.no