[1/2] Erlang programming ex3_10

ex3_10.erl

-module(ex3_10).
-export([format/2]).

format(Text, Width) -> do_format(Text, Width, Width).

do_format([], _, _) -> ok;
do_format(Text, _, Width) when length(Text) < Width -> io:format("~p~n", [Text]);
do_format([H | T], Width, 0) -> display_long_word([H | T], Width, []);
do_format(Text, Width, Request) ->
    Len = length(Text),
    Head = lists:sublist(Text, Request),
    Last = lists:last(Head),
    Remain = lists:sublist(Text, Request+1, Len-Request),
    Next = lists:nth(1, Remain),
    case [Last] of
        " " -> io:format("~p~n", [lists:sublist(Head, length(Head)-1)]),
               do_format(Remain, Width, Width);
        _ ->
            case [Next] of
                " " -> io:format("~p~n", [Head]),
                       do_format(lists:sublist(Remain, 2, length(Remain)-1), Width, Width);
                _ -> do_format(Text, Width, Request-1)
            end
    end.
            
display_long_word([H | T], Width, R) when [H] /= " " -> 
    NewR = lists:append(R, [H]),
    display_long_word(T, Width, NewR);
display_long_word(List, Width, R) ->
    io:format("~p~n", [R]),
    do_format(lists:sublist(List, 2, length(List)-1), Width, Width).


%%% test input:
ex3_10:format("Write a function that will print this in a readable form, so that duplicates are removed and adjacent numbers are put into a range. You might like to think of doing this via a function which turns the earlier list of occurrences into a list like [{1,2},{4,6},{98,98},{100,100},{102,102}] through a sequence of transformations.", 30).