[Format range] Add --range as a command line option.

src/erlfmt.erl

@@ -18,16 +18,20 @@
     main/1,
     init/1,
     format_file/2,
-    format_file_range/4,
     format_string/2,
-    format_string_range/4,
     format_nodes/2,
     read_nodes/1,
     read_nodes_string/2,
     format_error/1,
     format_error_info/1
 ]).
 
+% For unit tests
+-export([
+    format_file_range/4,
+    format_string_range/4
+]).
+
 -export_type([error_info/0, config/0, pragma/0]).
 
 -type error_info() :: {file:name_all(), erl_anno:location(), module(), Reason :: any()}.
@@ -62,6 +66,18 @@ init(State) ->
 -spec format_file(file:name_all() | stdin, config()) ->
     {ok, [unicode:chardata()], [error_info()]} | {skip, string()} | {error, error_info()}.
 format_file(FileName, Options) ->
+    Range = proplists:get_value(range, Options),
+    case Range of
+        undefined ->
+            % Whole file (default).
+            format_file_full(FileName, Options);
+        {Start, End} ->
+            format_file_range(FileName, {Start, 1}, {End, ?DEFAULT_WIDTH}, Options)
+    end.
+
+-spec format_file_full(file:name_all() | stdin, config()) ->
+    {ok, [unicode:chardata()], [error_info()]} | {skip, string()} | {error, error_info()}.
+format_file_full(FileName, Options) ->
     PrintWidth = proplists:get_value(print_width, Options, ?DEFAULT_WIDTH),
     Pragma = proplists:get_value(pragma, Options, ignore),
     try
@@ -91,6 +107,21 @@ format_file(FileName, Options) ->
 -spec format_string(string(), config()) ->
     {ok, string(), [error_info()]} | {skip, string()} | {error, error_info()}.
 format_string(String, Options) ->
+    Range = proplists:get_value(range, Options),
+    case Range of
+        undefined ->
+            % Whole file (default).
+            format_string_full(String, Options);
+        {Start, End} ->
+            % Remove 'range' property: when applicable we pass explictly the range instead.
+            % Also, match specifition of format_string_range.
+            Options2 = proplists:remove(range, Options),
+            format_string_range(String, {Start, 1}, {End, ?DEFAULT_WIDTH}, Options2)
+    end.
+
+-spec format_string_full(string(), config()) ->
+    {ok, string(), [error_info()]} | {skip, string()} | {error, error_info()}.
+format_string_full(String, Options) ->
     PrintWidth = proplists:get_value(print_width, Options, ?DEFAULT_WIDTH),
     Pragma = proplists:get_value(pragma, Options, ignore),
     try

src/erlfmt_cli.erl

@@ -21,7 +21,8 @@
     verbose = false :: boolean(),
     print_width = undefined :: undefined | pos_integer(),
     pragma = ignore :: erlfmt:pragma(),
-    out = standard_out :: out()
+    out = standard_out :: out(),
+    range = undefined :: undefined | {pos_integer(), pos_integer()}
 }).
 
 -type parsed() :: {format, list(), list(), #config{}} | help | version | {error, string()}.
@@ -50,6 +51,11 @@ opts() ->
         {delete_pragma, undefined, "delete-pragma", undefined,
             "Deletes the @format pragma at the top of formatted files. "
             "It will also reformat the file, but is only applied to files with a pragma, see --require-pragma."},
+        % The getopt module doesn't support tuple of integers as a type,
+        % So we accept a string, and do an ad-hoc parsing manually.
+        {range, undefined, "range", string,
+            "Range to be formatted in start-end format (both inclusive). "
+            "Warning! A bigger range might end up being formatted, as for now the format granularity is top-level form."},
         {exclude_files, undefined, "exclude-files", string,
             "files not to format. "
             "This overrides the files specified to format"},
@@ -156,21 +162,27 @@ unprotected_with_config(Name, ParsedConfig) ->
     end.
 
 format_file(FileName, Config) ->
-    #config{pragma = Pragma, print_width = PrintWidth, verbose = Verbose, out = Out} = Config,
+    #config{pragma = Pragma, print_width = PrintWidth, verbose = Verbose, out = Out, range = Range} =
+        Config,
     case Verbose of
         true -> io:format(standard_error, "Formatting ~s\n", [FileName]);
         false -> ok
     end,
     Options =
         [{pragma, Pragma}] ++
             [{print_width, PrintWidth} || PrintWidth =/= undefined] ++
-            [verbose || Verbose],
+            [verbose || Verbose] ++
+            [{range, Range} || range =/= undefined],
     Result =
-        case {Out, FileName} of
-            {check, stdin} ->
+        case {Range, Out, FileName} of
+            {undefined, check, stdin} ->
                 check_stdin(Options);
-            {check, _} ->
+            {undefined, check, _} ->
                 check_file(FileName, Options);
+            {{_, _}, check, _} ->
+                {error, "Checking of range not supported."};
+            {{_, _}, replace, _} ->
+                {error, "In place formatting of range not supported yet."};
             _ ->
                 erlfmt:format_file(FileName, Options)
         end,
@@ -311,6 +323,28 @@ parse_opts([delete_pragma | _Rest], _Files, _Exclude, #config{pragma = require})
     {error, "Cannot use both --require-pragma and --delete-pragma options together."};
 parse_opts([delete_pragma | Rest], Files, Exclude, Config) ->
     parse_opts(Rest, Files, Exclude, Config#config{pragma = delete});
+parse_opts([{range, String} | Rest], Files, Exclude, Config) ->
+    % Ad-hoc parsing. Mitigation for the absence of "couple of integers" direct support.
+    Range1 = string:split(String, ",", all),
+    Range2 = [list_to_integer(X) || X <- Range1],
+    Range3 =
+        case Range2 of
+            [X] ->
+                % Single line. Set end=start
+                [X, X];
+            [X, Y] ->
+                [X, Y];
+            _ ->
+                {error, "Range: Expected 1 argument (single line) or 2 (start, end)."}
+        end,
+    case Range3 of
+        [Start, End] when Start > End ->
+            {error, "Range: End must be greater or equal than Start."};
+        [Start, End] ->
+            parse_opts(Rest, Files, Exclude, Config#config{range = {Start, End}});
+        Error ->
+            Error
+    end;
 parse_opts([{files, NewFiles} | Rest], Files, Exclude, Config) ->
     parse_opts(Rest, expand_files(NewFiles, Files), Exclude, Config);
 parse_opts([{exclude_files, NewExcludes} | Rest], Files, Exclude, Config) ->
@@ -361,20 +395,23 @@ resolve_config(
         verbose = PreferVerbose,
         print_width = PreferWidth,
         pragma = PreferPragma,
-        out = PreferOut
+        out = PreferOut,
+        range = PreferRange
     },
     #config{
         verbose = DefaultVerbose,
         print_width = DefaultWidth,
         pragma = DefaultPragma,
-        out = DefaultOut
+        out = DefaultOut,
+        range = DefaultRange
     }
 ) ->
     #config{
         verbose = PreferVerbose orelse DefaultVerbose,
         print_width = resolve_width(PreferWidth, DefaultWidth),
         pragma = resolve_pragma(PreferPragma, DefaultPragma),
-        out = resolve_out(PreferOut, DefaultOut)
+        out = resolve_out(PreferOut, DefaultOut),
+        range = resolve_range(PreferRange, DefaultRange)
     }.
 
 resolve_width(undefined, W) -> W;
@@ -386,6 +423,9 @@ resolve_pragma(P, _) -> P.
 resolve_out(standard_out, O) -> O;
 resolve_out(O, _) -> O.
 
+resolve_range(undefined, R) -> R;
+resolve_range(R, _) -> R.
+
 specified_files(List) ->
     lists:filter(
         fun

test/erlfmt_cli_SUITE.erl

@@ -47,7 +47,8 @@
     smoke_test_stdio_reinsert_pragma_config/1,
     smoke_test_stdio_unicode/1,
     smoke_test_stdio_check/1,
-    exclude_check/1
+    exclude_check/1,
+    range_check/1
 ]).
 
 suite() ->
@@ -90,7 +91,8 @@ groups() ->
             smoke_test_stdio_reinsert_pragma_config,
             smoke_test_stdio_unicode,
             smoke_test_stdio_check,
-            exclude_check
+            exclude_check,
+            range_check
         ]}
     ].
 
@@ -236,6 +238,11 @@ exclude_check(Config) when is_list(Config) ->
     ?assertNotMatch(nomatch, string:find(WithoutBroken, "[warn]")),
     ?assertMatch(nomatch, string:find(WithoutBroken, "broken.erl")).
 
+range_check(Config) when is_list(Config) ->
+    %% Simply check the options is properly recognized.
+    %% Here the range is the whole file.
+    stdio_test("attributes.erl", "--range=1,56", Config).
+
 %%--------------------------------------------------------------------
 %% HELPERS