Adding documentation

src/esqlite.erl

@@ -5,7 +5,23 @@
 -module(esqlite).
 -author("Maas-Maarten Zeeman <mmzeeman@xs4all.nl>").
 
--export([open/1, open/2, exec/2, prepare/2, prepare/3, step/1, step/2, bind/2, bind/3, exec/3, close/1, close/2]).
+%% higher-level export
+-export([open/1, open/2, 
+	 exec/2, exec/3,
+	 prepare/2, prepare/3, 
+	 step/1, step/2, 
+	 bind/2, bind/3, 
+	 close/1, close/2]).
+
+%% low-level exports
+-export([esqlite_start/0, 
+	 esqlite_open/4, 
+	 esqlite_exec/4, 
+	 esqlite_prepare/4,
+	 esqlite_step/3,
+	 esqlite_bind/4,
+	 esqlite_close/3
+]).
 
 -on_load(init/0).
 
@@ -14,13 +30,15 @@
 init() ->
     ok = erlang:load_nif(code:priv_dir(esqlite) ++ "/esqlite_nif", 0).
 
-%% @doc Open a new database connection
+%% @doc Opens a sqlite3 database mentioned in Filename.
 %%
+%% @spec open(string()) -> {ok, connection()} | {error, error_message()}
 open(Filename) ->
     open(Filename, ?DEFAULT_TIMEOUT).
 
 %% @doc Open a database connection
 %%
+%% @spec open(string(), integer()) -> {ok, connection()} | {error, error_message()}
 open(Filename, Timeout) ->
     {ok, Db} = esqlite_start(),
 
@@ -35,41 +53,55 @@ open(Filename, Timeout) ->
 
 %% @doc Execute Sql statement
 %%
+%% @spec exec(connection(), iolist()) -> integer() |  {error, error_message()}
 exec(Db, Sql) ->
     exec(Db, Sql, ?DEFAULT_TIMEOUT).
 
+%% @doc Execute 
+%%
+%% @spec exec(connection(), iolist(), integer()) -> integer() | {error, error_message()}
 exec(Db, Sql, Timeout) ->
     Ref = make_ref(),
-    %% sqlite doesn't support length parameters for queries... add the
+    ok = esqlite_exec(Db, Ref, self(), add_eos(Sql)),
-    %% end of string here.
-    ok = esqlite_exec(Db, Ref, self(), [Sql, 0]),
     receive_answer(Ref, Timeout).
 
 %% @doc Prepare a statement
 %%
+%% @spec prepare(connection(), iolist()) -> {ok, prepared_statement()} | {error, error_message()}
 prepare(Db, Sql) ->
     prepare(Db, Sql, ?DEFAULT_TIMEOUT).
 
+%% @doc
+%%
+%% @spec(connection(), iolist()) -> {ok, prepared_statement()} | {error, error_message()}
 prepare(Db, Sql, Timeout) ->
     Ref = make_ref(),
-    ok = esqlite_prepare(Db, Ref, self(), [Sql, 0]),
+    ok = esqlite_prepare(Db, Ref, self(), add_eos(Sql)),
     receive_answer(Ref, Timeout).
 
 %% @doc Step
 %%
+%% @spec step(prepared_statement()) -> tuple()
 step(Stmt) ->
     step(Stmt, ?DEFAULT_TIMEOUT).
 
+%% @doc 
+%%
+%% @spec step(prepared_statement(), integer()) -> tuple()
 step(Stmt, Timeout) ->
     Ref = make_ref(),
     ok = esqlite_step(Stmt, Ref, self()),
     receive_answer(Ref, Timeout).
 
-%% @doc Bind
+%% @doc Bind values to prepared statements
 %%
+%% @spec bind(prepared_statement(), value_list()) -> ok | {error, error_message()}
 bind(Stmt, Args) ->
     bind(Stmt, Args, ?DEFAULT_TIMEOUT).
 
+%% @doc Bind values to prepared statements
+%%
+%% @spec bind(prepared_statement()) -> ok | {error, error_message()}
 bind(Stmt, Args, Timeout) ->
     Ref = make_ref(),
     ok = esqlite_bind(Stmt, Ref, self(), Args),
@@ -77,36 +109,52 @@ bind(Stmt, Args, Timeout) ->
 
 %% @doc Close the database
 %%
+%% @spec close(connection()) -> ok | {error, error_message()}
 close(Db) ->
     close(Db, ?DEFAULT_TIMEOUT).
 
+%% @doc Close the database
+%%
+%% @spec close(connection(), integer()) -> ok | {error, error_message()}
 close(Db, Timeout) ->
     Ref = make_ref(),
     ok = esqlite_close(Db, Ref, self()),
     receive_answer(Ref, Timeout).
 
-%% ---- Internal ----
+%% @doc
+%%
 esqlite_start() ->
     exit(nif_library_not_loaded).
 
+%% @doc
 esqlite_open(_Db, _Ref, _Dest, _Filename) ->
     exit(nif_library_not_loaded).
 
+%% @doc
 esqlite_exec(_Db, _Ref, _Dest, _Sql) ->
     exit(nif_library_not_loaded).
 
+%% @doc
 esqlite_prepare(_Db, _Ref, _Dest, _Sql) ->
     exit(nif_library_not_loaded).
 
+%% @doc
 esqlite_step(_Stmt, _Ref, _Dest) ->
     exit(nif_library_not_loaded).
 
+%% @doc
 esqlite_bind(_Stmt, _Ref, _Dest, _Args) ->
     exit(nif_library_not_loaded).
 
+%% @doc
 esqlite_close(_Db, _Ref, _Dest) ->
     exit(nif_library_not_loaded).
 
+%% Internal functions
+
+add_eos(String) when is_list(String) ->
+    [String, 0].
+
 receive_answer(Ref, Timeout) ->
     receive 
 	{Ref, Resp} ->

src/sqlite.erl

@@ -1,3 +1,7 @@
+%%
+%% Exploring making a database driver for the generic gen_db interface
+%%
+
 -module(sqlite).
 
 -behaviour(gen_db).

test/esqlite_test.erl

@@ -73,6 +73,13 @@ bind_test() ->
 
     ok.
 
+gen_db_test() ->
+    {ok, Conn} = gen_db:open(sqlite, ":memory:"),
+    [] = gen_db:execute("create table some_shit(hole_one varchar(10), hole_two int);", [], Conn),
+    [] = gen_db:execute("insert into some_shit values('dung', 100);", Conn),
+    [] = gen_db:execute("insert into some_shit values(?, ?);", ["manure", 1000], Conn),
+    ok.
+
 
 %% Handy functions...
 %%