Format a column-map resolution line for verbose output

Produces a single string like: "fn(): column map: G0 -> 'col_a', I0 -> 'col_b', ..."

Usage

hm_fmt_col_map(col_map, fn = NULL)

Arguments

col_map

Named list of key -> column-name mappings (only the keys actually used by the function need to be supplied).

fn

Optional function name prefixed to the message.