parnames() is brms's deprecated spelling of variables(). brms
still answers it, with a deprecation warning, so a ported script
runs; this does the same. The generic is defined here and not in
frmtmb.sample, which answers it on draws, so that one generic serves
both classes.
Examples
dd <- data.frame(x = rnorm(60))
dd$y <- rnorm(60, 1 + 0.5 * dd$x)
fit <- frm(bf(y ~ x), family = gaussian(), data = dd)
suppressWarnings(parnames(fit))
#> [1] "b_Intercept" "b_x" "sigma"