diff --git a/src/aeso_compiler.erl b/src/aeso_compiler.erl
index 7d34ad5..3080e53 100644
--- a/src/aeso_compiler.erl
+++ b/src/aeso_compiler.erl
@@ -22,7 +22,7 @@
 
 
 -type option() :: pp_sophia_code | pp_ast | pp_types | pp_typed_ast |
-		  pp_icode| pp_assembler | pp_bytecode.
+                  pp_icode| pp_assembler | pp_bytecode.
 -type options() :: [option()].
 
 -export_type([ option/0
@@ -38,50 +38,50 @@
 version() ->
     ?COMPILER_VERSION.
 
--spec file(string()) -> map().
+-spec file(string()) -> {ok, map()} | {error, binary()}.
 file(Filename) ->
     file(Filename, []).
 
--spec file(string(), options()) -> map().
+-spec file(string(), options()) -> {ok, map()} | {error, binary()}.
 file(File, Options) ->
     case read_contract(File) of
         {ok, Bin} -> from_string(Bin, Options);
         {error, Error} -> {error, {File, Error}}
     end.
 
--spec from_string(binary() | string(), options()) -> map().
+-spec from_string(binary() | string(), options()) -> {ok, map()} | {error, binary()}.
 from_string(ContractBin, Options) when is_binary(ContractBin) ->
     from_string(binary_to_list(ContractBin), Options);
 from_string(ContractString, Options) ->
     try
-	Ast = parse(ContractString, Options),
-	ok = pp_sophia_code(Ast, Options),
-	ok = pp_ast(Ast, Options),
-	TypedAst = aeso_ast_infer_types:infer(Ast, Options),
-	%% pp_types is handled inside aeso_ast_infer_types.
-	ok = pp_typed_ast(TypedAst, Options),
-	ICode = to_icode(TypedAst, Options),
-	TypeInfo = extract_type_info(ICode),
-	ok = pp_icode(ICode, Options),
-	Assembler =  assemble(ICode, Options),
-	ok = pp_assembler(Assembler, Options),
-	ByteCodeList = to_bytecode(Assembler, Options),
-	ByteCode = << << B:8 >> || B <- ByteCodeList >>,
-	ok = pp_bytecode(ByteCode, Options),
-	{ok,#{byte_code => ByteCode,
-	      compiler_version => version(),
-	      contract_source => ContractString,
-	      type_info => TypeInfo
-	     }}
+        Ast = parse(ContractString, Options),
+        ok = pp_sophia_code(Ast, Options),
+        ok = pp_ast(Ast, Options),
+        TypedAst = aeso_ast_infer_types:infer(Ast, Options),
+        %% pp_types is handled inside aeso_ast_infer_types.
+        ok = pp_typed_ast(TypedAst, Options),
+        ICode = to_icode(TypedAst, Options),
+        TypeInfo = extract_type_info(ICode),
+        ok = pp_icode(ICode, Options),
+        Assembler =  assemble(ICode, Options),
+        ok = pp_assembler(Assembler, Options),
+        ByteCodeList = to_bytecode(Assembler, Options),
+        ByteCode = << << B:8 >> || B <- ByteCodeList >>,
+        ok = pp_bytecode(ByteCode, Options),
+        {ok, #{byte_code => ByteCode,
+               compiler_version => version(),
+               contract_source => ContractString,
+               type_info => TypeInfo
+              }}
     catch
         %% The compiler errors.
-        error:{parse_errors,Errors} ->
-	    {error,join_errors("Parse errors", Errors, fun(E) -> E end)};
-        error:{type_errors,Errors} ->
-	    {error,join_errors("Type errors", Errors, fun(E) -> E end)};
-        error:{code_errors,Errors} ->
-            {error,join_errors("Code errors", Errors,
-			       fun (E) -> io_lib:format("~p", [E]) end)}
+        error:{parse_errors, Errors} ->
+            {error, join_errors("Parse errors", Errors, fun(E) -> E end)};
+        error:{type_errors, Errors} ->
+            {error, join_errors("Type errors", Errors, fun(E) -> E end)};
+        error:{code_errors, Errors} ->
+            {error, join_errors("Code errors", Errors,
+                                fun (E) -> io_lib:format("~p", [E]) end)}
         %% General programming errors in the compiler just signal error.
     end.
 
@@ -99,35 +99,35 @@ join_errors(Prefix, Errors, Pfun) ->
     when Type :: term().
 check_call(ContractString, Options) ->
     try
-	Ast = parse(ContractString, Options),
-	ok = pp_sophia_code(Ast, Options),
-	ok = pp_ast(Ast, Options),
-	TypedAst = aeso_ast_infer_types:infer(Ast, [permissive_address_literals]),
-	{ok, {FunName, {fun_t, _, _, ArgTypes, RetType}}} = get_call_type(TypedAst),
-	ok = pp_typed_ast(TypedAst, Options),
-	Icode = to_icode(TypedAst, Options),
-	ArgVMTypes = [ aeso_ast_to_icode:ast_typerep(T, Icode) || T <- ArgTypes ],
-	RetVMType  = case RetType of
-			 {id, _, "_"} -> any;
-			 _            -> aeso_ast_to_icode:ast_typerep(RetType, Icode)
-		     end,
-	ok = pp_icode(Icode, Options),
-	#{ functions := Funs } = Icode,
-	ArgIcode = get_arg_icode(Funs),
-	ArgTerms = [ icode_to_term(T, Arg) ||
-		       {T, Arg} <- lists:zip(ArgVMTypes, ArgIcode) ],
-	{ok, FunName, {ArgVMTypes, RetVMType}, ArgTerms}
+        Ast = parse(ContractString, Options),
+        ok = pp_sophia_code(Ast, Options),
+        ok = pp_ast(Ast, Options),
+        TypedAst = aeso_ast_infer_types:infer(Ast, [permissive_address_literals]),
+        {ok, {FunName, {fun_t, _, _, ArgTypes, RetType}}} = get_call_type(TypedAst),
+        ok = pp_typed_ast(TypedAst, Options),
+        Icode = to_icode(TypedAst, Options),
+        ArgVMTypes = [ aeso_ast_to_icode:ast_typerep(T, Icode) || T <- ArgTypes ],
+        RetVMType  = case RetType of
+                         {id, _, "_"} -> any;
+                         _            -> aeso_ast_to_icode:ast_typerep(RetType, Icode)
+                     end,
+        ok = pp_icode(Icode, Options),
+        #{ functions := Funs } = Icode,
+        ArgIcode = get_arg_icode(Funs),
+        ArgTerms = [ icode_to_term(T, Arg) ||
+                       {T, Arg} <- lists:zip(ArgVMTypes, ArgIcode) ],
+        {ok, FunName, {ArgVMTypes, RetVMType}, ArgTerms}
     catch
-	error:{parse_errors, Errors} ->
-	    {error,join_errors("Parse errors", Errors, fun (E) -> E end)};
-	error:{type_errors, Errors} ->
-	    {error,join_errors("Type errors", Errors, fun (E) -> E end)};
-	error:{badmatch,{error,missing_call_function}} ->
-	    {error,join_errors("Type errors", ["missing __call function"],
-			       fun (E) -> E end)};
-	throw:Error ->				%Don't ask
-            {error,join_errors("Code errors", [Error],
-			       fun (E) -> io_lib:format("~p", [E]) end)}
+        error:{parse_errors, Errors} ->
+            {error, join_errors("Parse errors", Errors, fun (E) -> E end)};
+        error:{type_errors, Errors} ->
+            {error, join_errors("Type errors", Errors, fun (E) -> E end)};
+        error:{badmatch, {error, missing_call_function}} ->
+            {error, join_errors("Type errors", ["missing __call function"],
+                                fun (E) -> E end)};
+        throw:Error ->                          %Don't ask
+            {error, join_errors("Code errors", [Error],
+                                fun (E) -> io_lib:format("~p", [E]) end)}
     end.
 
 -spec create_calldata(map(), string(), string()) ->
@@ -279,9 +279,9 @@ parse_string(Text) ->
             parse_error(Pos, ErrorString)
     end.
 
-parse_error({Line,Pos}, ErrorString) ->
-    Error = io_lib:format("line ~p, column ~p: ~s", [Line,Pos,ErrorString]),
-    error({parse_errors,[Error]}).
+parse_error({Line, Pos}, ErrorString) ->
+    Error = io_lib:format("line ~p, column ~p: ~s", [Line, Pos, ErrorString]),
+    error({parse_errors, [Error]}).
 
 read_contract(Name) ->
     file:read_file(Name).