Is it possible to use a continuous predictor in Bugs? The simplest way of doing this would be turning the size variable in alligators example from discrete to continuous.
Both Winbugs and JAGS examples use combination of values of covariates as indices as in
X[i,j,] ~ dmulti( p[i,j,] , n[i,j] );
i is the lake index (4 possible values), and
j is the size index (2 possible values). With this approach, a continuous size variable would mean an infinite amount of indices. There must be something I'm missing here.