S-code for piecewise regression

Dear R-helpers,
a S-code for piecewise regressions was provided by Toms & Lesperance 
(2003) Ecology, 84, 2034-2041 (paper can be found on the web).The code 
is quite complete with different types of transitions around breakpoints 
and model selection fonctions.
It doesn't work directly under R due to some "translation" problems I 
guess. However I  reckon that  it would be a  valuable  add-on to R, so 
if anyone that knows both S and R syntax (I don't) doesn't know what to 
do during the week-end, it could provide some entertainment...
attached is the code.
regards,
simon
" R is love" (L.D.)
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