* add folding for collections + structs

* add list syntax

Fixes elixir-editors#539

spec/folding/basic_spec.rb

@@ -45,4 +45,52 @@ def some_func do # fold
   end # fold
   "not in fold"
   EOF
+
+  fold <<~EOF
+  defmodule M do
+    def some_func do
+      [ # fold
+        :hello, # fold
+        :world # fold
+      ] # fold
+      :hello_world
+    end
+  end
+  EOF
+
+  fold <<~EOF
+  defmodule M do
+    def some_func do
+      { # fold
+        :hello, # fold
+        :world # fold
+      } # fold
+      :hello_world
+    end
+  end
+  EOF
+
+  fold <<~EOF
+  defmodule M do
+    def some_func do
+      %{ # fold
+        hello: "a", # fold
+        world: "b" # fold
+      } # fold
+      :hello_world
+    end
+  end
+  EOF
+
+  fold <<~EOF
+  defmodule M do
+    def some_func do
+      %User{ # fold
+        hello: "a", # fold
+        world: "b" # fold
+      } # fold
+      :hello_world
+    end
+  end
+  EOF
 end

spec/syntax/list_spec.rb

@@ -11,4 +11,30 @@
     expect(syntax).to include_elixir_syntax('elixirId', 'var')
     expect(syntax).not_to include_elixir_syntax('elixirString', 'var')
   end
+
+  it 'recognizes lists' do
+    syntax = <<~EOF
+    [
+      :hello,
+      :world
+    ]
+    EOF
+    expect(syntax).to include_elixir_syntax('elixirListDelimiter', '[')
+    expect(syntax).to include_elixir_syntax('elixirList', ':hello')
+    expect(syntax).to include_elixir_syntax('elixirListDelimiter', ']')
+  end
+
+  it 'recognizes lists inside functions' do
+    syntax = <<~EOF
+    def hello_world do
+      [
+        :hello,
+        :world
+      ]
+    end
+    EOF
+    expect(syntax).to include_elixir_syntax('elixirListDelimiter', '[')
+    expect(syntax).to include_elixir_syntax('elixirList', ':hello')
+    expect(syntax).to include_elixir_syntax('elixirListDelimiter', ']')
+  end
 end

syntax/elixir.vim

@@ -8,7 +8,7 @@ endif
 let s:cpo_save = &cpo
 set cpo&vim
 
-syn cluster elixirNotTop contains=@elixirRegexSpecial,@elixirStringContained,@elixirDeclaration,elixirTodo,elixirArguments,elixirBlockDefinition,elixirUnusedVariable,elixirStructDelimiter
+syn cluster elixirNotTop contains=@elixirRegexSpecial,@elixirStringContained,@elixirDeclaration,elixirTodo,elixirArguments,elixirBlockDefinition,elixirUnusedVariable,elixirStructDelimiter,elixirListDelimiter
 syn cluster elixirRegexSpecial contains=elixirRegexEscape,elixirRegexCharClass,elixirRegexQuantifier,elixirRegexEscapePunctuation
 syn cluster elixirStringContained contains=elixirInterpolation,elixirRegexEscape,elixirRegexCharClass
 syn cluster elixirDeclaration contains=elixirFunctionDeclaration,elixirPrivateFunctionDeclaration,elixirModuleDeclaration,elixirProtocolDeclaration,elixirImplDeclaration,elixirRecordDeclaration,elixirPrivateRecordDeclaration,elixirMacroDeclaration,elixirPrivateMacroDeclaration,elixirDelegateDeclaration,elixirOverridableDeclaration,elixirExceptionDeclaration,elixirCallbackDeclaration,elixirStructDeclaration
@@ -66,12 +66,15 @@ syn match elixirRegexCharClass         "\[:\(alnum\|alpha\|ascii\|blank\|cntrl\|
 
 syn region elixirRegex matchgroup=elixirRegexDelimiter start="%r/" end="/[uiomxfr]*" skip="\\\\" contains=@elixirRegexSpecial
 
-syn region elixirTuple matchgroup=elixirTupleDelimiter start="\(\w\|#\)\@<!{" end="}" contains=ALLBUT,@elixirNotTop
+syn region elixirTuple matchgroup=elixirTupleDelimiter start="\(\w\|#\)\@<!{" end="}" contains=ALLBUT,@elixirNotTop fold
+
+syn match elixirListDelimiter '\[' contained containedin=elixirList
+syn region elixirList matchgroup=elixirListDelimiter start='\[' end='\]' contains=ALLBUT,@elixirNotTop fold
 
 syn match elixirStructDelimiter '{' contained containedin=elixirStruct
-syn region elixirStruct matchgroup=elixirStructDelimiter start="%\(\w\+{\)\@=" end="}" contains=ALLBUT,@elixirNotTop
+syn region elixirStruct matchgroup=elixirStructDelimiter start="%\(\w\+{\)\@=" end="}" contains=ALLBUT,@elixirNotTop fold
 
-syn region elixirMap matchgroup=elixirMapDelimiter start="%{" end="}" contains=ALLBUT,@elixirNotTop
+syn region elixirMap matchgroup=elixirMapDelimiter start="%{" end="}" contains=ALLBUT,@elixirNotTop fold
 
 syn region elixirString  matchgroup=elixirStringDelimiter start=+\z('\)+   end=+\z1+ skip=+\\\\\|\\\z1+  contains=@Spell,@elixirStringContained
 syn region elixirString  matchgroup=elixirStringDelimiter start=+\z("\)+   end=+\z1+ skip=+\\\\\|\\\z1+  contains=@Spell,@elixirStringContained