A syntax-aware editor's highlighting or automatic indentation could provide an extra clue, though. It can scan for periods quite easily.
Prolog and Erlang (which was initially implemented in Prolog) use periods to end blocks, as well. While it can make rearranging expressions in a block a little annoying ("," vs "." in Prolog, "," and ";" vs "." in Erlang), it's small potatoes compared to the syntactic quirks in, say, C.
Also, Lua does the same "table as an argument -> keyword arguments" trick. (He mentions Lua in the list of influences.)
Prolog and Erlang (which was initially implemented in Prolog) use periods to end blocks, as well. While it can make rearranging expressions in a block a little annoying ("," vs "." in Prolog, "," and ";" vs "." in Erlang), it's small potatoes compared to the syntactic quirks in, say, C.
Also, Lua does the same "table as an argument -> keyword arguments" trick. (He mentions Lua in the list of influences.)