Replacing matching sublists in Erlang

replace_matching_sublist.erl

-module(helloworld). 
-import(lists,[append/2]). 
-export([start/0]). 

replace_if_match(X) ->
case X of
    [A, "equals", B | Tail ] ->
        [[A,"==",B],replace_if_match(Tail)];
    [A, "is", B | Tail ] ->
        [[A,"==",B],replace_if_match(Tail)];
    [A, "is","equal","to", B | Tail ] ->
        [[A,"==",B],replace_if_match(Tail)];
    [Head | Tail] ->
        [Head|replace_if_match(Tail)];
    [] -> []
end.

start() -> 
   Lst1 = ["A", "is", ["1","+","1"], "and", "B","equals",["2","+","A"]], 
   io:fwrite(replace_if_match(Lst1)). % prints "A==1+1andB==2+A"