Merge pull request #45 from inaka/jfacorro.14.improvements

[#14] Modified AST node generation for 'case' and list comprehension

src/elvis_code.erl

@@ -2,7 +2,9 @@
 
 -export([
          parse_tree/1,
-         past_nesting_limit/2
+         past_nesting_limit/2,
+         print_node/1,
+         print_node/2
         ]).
 
 -export([
@@ -75,6 +77,18 @@ past_nesting_limit(#{content := Content},
 past_nesting_limit(_Node, _CurrentLeve, _MaxLevel) ->
     [].
 
+%% @doc Debugging utility function.
+-spec print_node(tree_node()) -> ok.
+print_node(Node) ->
+    print_node(Node, 0).
+
+-spec print_node(tree_node(), integer()) -> ok.
+print_node(Node = #{type := Type}, CurrentLevel) ->
+    Indentation = lists:duplicate(CurrentLevel * 4, 32),
+    {Line, _} = elvis_code:attr(location, Node),
+    lager:info("~s - [~p] ~p : ~p~n",
+               [Indentation, CurrentLevel, Type, Line]).
+
 %% @private
 %% @doc Takes a node type and determines its nesting level increment.
 level_increment(Type) ->
@@ -206,9 +220,19 @@ to_map({remote, Location, Module, Function}) ->
 %% case
 
 to_map({'case', Location, Expr, Clauses}) ->
+    CaseExpr = to_map({case_expr, Location, Expr}),
+    CaseClauses = to_map({case_clauses, Location, Clauses}),
     #{type => 'case',
       attrs => #{location => Location,
                  expression => to_map(Expr)},
+      content => [CaseExpr, CaseClauses]};
+to_map({case_expr, Location, Expr}) ->
+    #{type => case_expr,
+      attrs => #{location => Location},
+      content => [to_map(Expr)]};
+to_map({case_clauses, Location, Clauses}) ->
+    #{type => case_clauses,
+      attrs => #{location => Location},
       content => to_map(Clauses)};
 
 %% fun
@@ -359,15 +383,21 @@ to_map({Type, Location, Key, Value}) when
 %% List Comprehension
 
 to_map({lc, Location, Expr, GeneratorsFilters}) ->
+    LcExpr = to_map({lc_expr, Location, Expr}),
+    LcGenerators = to_map(GeneratorsFilters),
     #{type => lc,
-      attrs => #{location => Location,
-                 expression => to_map(Expr)},
-      content => to_map(GeneratorsFilters)};
+      attrs => #{location => Location},
+      content => [LcExpr | LcGenerators]};
+
 to_map({generate, Location, Pattern, Expr}) ->
     #{type => generate,
       attrs => #{location => Location,
                  pattern => to_map(Pattern),
                  expression => to_map(Expr)}};
+to_map({lc_expr, Location, Expr}) ->
+    #{type => lc_expr,
+      attrs => #{location => Location},
+      content => [to_map(Expr)]};
 
 %% Operation
 

src/elvis_utils.erl

@@ -2,14 +2,22 @@
 
 -export([
          src/2,
+
+         %% Files
          find_files/1,
          find_files/2,
+         is_erlang_file/1,
+         filter_files/1,
+
+         %% Rules
          check_lines/3,
+         check_lines_with_context/4,
+         indentation/3,
          check_nodes/3,
+
+         %% General
          erlang_halt/1,
-         to_str/1,
-         is_erlang_file/1,
-         filter_files/1
+         to_str/1
         ]).
 
 -export_type([file/0]).
@@ -57,6 +65,13 @@ check_lines(Src, Fun, Args) ->
     Lines = binary:split(Src, <<"\n">>, [global]),
     check_lines(Lines, Fun, Args, [], 1).
 
+-spec check_lines_with_context(binary(), fun(), [term()], {integer(), integer()}) ->
+    [elvis_result:item()].
+check_lines_with_context(Src, Fun, Args, Ctx) ->
+    Lines = binary:split(Src, <<"\n">>, [global]),
+    LinesContext = context(Lines, Ctx),
+    check_lines(LinesContext, Fun, Args, [], 1).
+
 %% @private
 check_lines([], _Fun, _Args, Results, _Num) ->
     lists:reverse(Results);
@@ -68,6 +83,18 @@ check_lines([Line | Lines], Fun, Args, Results, Num) ->
             check_lines(Lines, Fun, Args, Results, Num + 1)
     end.
 
+%% @private
+context(List, CtxCount) ->
+    context(List, [], CtxCount, []).
+
+context([], _Past, _CtxCount, Results) ->
+    lists:reverse(Results);
+context([Current | Future], Past, CtxCount = {PrevCount, NextCount}, Results) ->
+    Prev = lists:sublist(Past, PrevCount),
+    Next = lists:sublist(Future, NextCount),
+    Item = {Current, lists:reverse(Prev), Next},
+    context(Future, [Current | Past], CtxCount, [Item | Results]).
+
 %% @doc Takes a binary that holds source code and applies
 %% Fun to each line. Fun takes 3 arguments (the line
 %% as a binary, the line number and the supplied Args) and
@@ -114,3 +141,16 @@ is_erlang_file(Path) ->
 filter_files(Files) ->
     [File || File = #{path := Path} <- Files,
              is_erlang_file(Path)].
+
+%% @doc Takes a line, a character and a count, returning the indentation level
+%%      invalid if the number of character is not a multiple of count.
+-spec indentation(binary() | string(), char(), integer()) ->
+    invalid | integer().
+indentation(Line, Char, Count) ->
+    LineStr = to_str(Line),
+    Regex = "^" ++ [Char] ++ "*",
+    {match, [{0, Len} | _]} = re:run(LineStr, Regex),
+    case Len rem Count of
+        0 -> Len div Count;
+        _ -> invalid
+    end.

test/examples/fail_nesting_level.erl

@@ -124,7 +124,7 @@ exceed_with_receive() ->
         3 -> 3
     end.
 
-exceed_with_receive_after() ->
+dont_exceed_with_receive_after() ->
     case 1 of
         1 -> ok;
         2 -> receive
@@ -140,3 +140,33 @@ exceed_with_receive_after() ->
              end;
         3 -> 3
     end.
+
+dont_exceed_with_list_compr() ->
+    case 1 of
+        1 -> ok;
+        2 -> receive
+                 1 -> ok;
+                 2 -> ok;
+                 3 -> ok
+             after
+                 1000 ->
+                     [X || X <- [1, 2, 3]]
+             end;
+        3 -> 3
+    end.
+
+exceed_with_list_compr() ->
+    case 1 of
+        1 -> ok;
+        2 -> receive
+                 1 -> ok;
+                 2 -> ok;
+                 3 -> [case X of
+                           1 -> ok;
+                           _ -> not_ok
+                       end
+                       || X <- [1, 2, 3]];
+                 4 -> ok
+             end;
+        3 -> 3
+    end.

test/rules_SUITE.erl

@@ -126,4 +126,5 @@ verify_nesting_level(_Config) ->
      #{line_num := 28},
      #{line_num := 43},
      #{line_num := 76},
-     #{line_num := 118}] = elvis_style:nesting_level(ElvisConfig, File, [3]).
+     #{line_num := 118},
+     #{line_num := 164}] = elvis_style:nesting_level(ElvisConfig, File, [3]).