Feature: Add Surface language and integrate with Elixir (#1645)

* Add initial surface highlights & injections

* Additional surface highlights

* Filetype detection, fix injections

* Fix Elixir function highlight when left is an identifier

* Add surface parser

* Fix comment highlights

* Surface folds, indents, better highlights

* Highlight surface components & directives

* Restore comments Elixir injections

9 files changed, 93 insertions, 0 deletions

diff --git a/ftdetect/elixir.vim b/ftdetect/elixir.vim
new file mode 100644
index 00000000..b06597ce
--- /dev/null
+++ b/ftdetect/elixir.vim
@@ -0,0 +1,2 @@
+au BufRead,BufNewFile *.ex,*.exs,mix.lock set filetype=elixir
+au BufRead,BufNewFile *.eex,*.leex,*.heex set filetype=eelixir
diff --git a/ftdetect/surface.vim b/ftdetect/surface.vim
new file mode 100644
index 00000000..6fb2a69b
--- /dev/null
+++ b/ftdetect/surface.vim
@@ -0,0 +1 @@
+au BufRead,BufNewFile *.sface set filetype=surface
diff --git a/lua/nvim-treesitter/parsers.lua b/lua/nvim-treesitter/parsers.lua
index 2fa20fd7..afe02f70 100644
--- a/lua/nvim-treesitter/parsers.lua
+++ b/lua/nvim-treesitter/parsers.lua
@@ -261,6 +261,16 @@ list.elixir = {
   maintainers = { "@nifoc" },
 }
 
+list.surface = {
+  install_info = {
+    url = "https://github.com/connorlay/tree-sitter-surface",
+    files = { "src/parser.c" },
+    branch = "main",
+  },
+  filetype = "sface",
+  maintainers = { "@connorlay" },
+}
+
 list.ocaml = {
   install_info = {
     url = "https://github.com/tree-sitter/tree-sitter-ocaml",
diff --git a/queries/elixir/highlights.scm b/queries/elixir/highlights.scm
index bcbc4391..51c57494 100644
--- a/queries/elixir/highlights.scm
+++ b/queries/elixir/highlights.scm
@@ -78,6 +78,10 @@
  remote: [(atom) (module)] @type
  function: (function_identifier) @method)
 
+(dot_call
+ remote: (identifier) @variable
+ function: (function_identifier) @method)
+
 "fn" @keyword.function
 
 ; def, defp, defguard, ... everything that starts with def
diff --git a/queries/elixir/injections.scm b/queries/elixir/injections.scm
index 0f12cdba..02709add 100644
--- a/queries/elixir/injections.scm
+++ b/queries/elixir/injections.scm
@@ -8,3 +8,8 @@
    (sigil_start) @_start
    (sigil_content) @regex)
  (#match? @_start "~(r|R)[/</\\\"[({|]"))
+
+((sigil
+   (sigil_start) @_start
+   (sigil_content) @surface)
+ (#eq? @_start "~F\"\"\""))
diff --git a/queries/surface/folds.scm b/queries/surface/folds.scm
new file mode 100644
index 00000000..57763a6e
--- /dev/null
+++ b/queries/surface/folds.scm
@@ -0,0 +1,5 @@
+; Surface folds similar to HTML and includes blocks
+[
+  (tag)
+  (block)
+] @fold
diff --git a/queries/surface/highlights.scm b/queries/surface/highlights.scm
new file mode 100644
index 00000000..77b88c05
--- /dev/null
+++ b/queries/surface/highlights.scm
@@ -0,0 +1,46 @@
+; Surface text is highlighted as such
+(text) @text
+
+; Surface has two types of comments, both are highlighted as such
+(comment) @comment
+
+; Surface attributes are highlighted as HTML attributes
+(attribute_name) @tag.attribute
+
+; Attributes are highlighted as strings
+(attribute_value) @string
+
+; Surface blocks are highlighted as keywords
+[
+  (start_block) 
+  (end_block)
+  (subblock)
+] @keyword
+
+; Surface supports HTML tags and are highlighted as such
+[
+  (start_tag)
+  (end_tag)
+  (self_closing_tag)
+  (start_component)
+  (end_component)
+  (self_closing_component)
+] @tag.delimiter
+
+; Expressions are similar to string interpolation, and are highloghted as such
+(expression) @punctuation.special
+
+; Expressions should be highlighted as Elixir, fallback to special strings
+(expression_value) @string.special
+
+; Surface tags are highlighted as HTML
+(tag_name) @tag
+
+; Surface components are highlighted as types (Elixir modules)
+(component_name) @type
+
+; Surface directives are highlighted as keywords
+(directive_name) @keyword
+
+; Surface operators
+["="] @operator
diff --git a/queries/surface/indents.scm b/queries/surface/indents.scm
new file mode 100644
index 00000000..ad683575
--- /dev/null
+++ b/queries/surface/indents.scm
@@ -0,0 +1,12 @@
+; Surface indents like HTML, with the addition of blocks 
+[
+  (tag)
+  (block)
+] @indent
+
+; Dedent at the end of each tag, as well as a subblock
+[
+  (end_tag)
+  (end_block)
+  (subblock)
+] @branch
diff --git a/queries/surface/injections.scm b/queries/surface/injections.scm
new file mode 100644
index 00000000..928977a3
--- /dev/null
+++ b/queries/surface/injections.scm
@@ -0,0 +1,8 @@
+; Surface expressions and components are Elixir code
+[
+  (expression_value)
+  (component_name)
+] @elixir
+
+; Surface comments are nvim-treesitter comments
+(comment) @comment