fix(ts)(c/cpp): detect functions that return pointers (fix #25)

Side note: this unfortunately moves the symbol location forward in the
line to where the name starts, where before it was at the beginning of
the return type. Every time you add a pointer to the return type (e.g.
int* fn() or int** fn()) it creates a new treesitter wrapper node of
"pointer_declaration". Unfortunately there does not seem to currently be
a way to write a query for function_definition -> <any number for
children> -> function_declaration. Because of that, we must either
explicitly query for each level of pointer indirection, or just query
directly for the function_declaration. I have opted for the latter
because it is cleaner, but it has the side effect of changing the symbol
location slightly.

lua/aerial/backends/treesitter/language_kind_map.lua

@@ -7,7 +7,7 @@ return {
   cpp = {
     class_specifier = "Class",
     enum_specifier = "Enum",
-    function_definition = "Function",
+    function_declarator = "Function",
     struct_specifier = "Struct",
   },
   c_sharp = {

queries/c/aerial.scm

@@ -2,13 +2,5 @@
   type: [(enum_specifier) (struct_specifier)] @type
   declarator: (type_identifier) @name) @location
 
-(_
-  declarator: (pointer_declarator
-    declarator: (function_declarator
-      declarator: (identifier) @name) @type)
-) @location
-
-(_
-  declarator: (function_declarator
-    declarator: (identifier) @name) @type
-) @location
+(function_declarator
+  declarator: (identifier) @name) @type

queries/cpp/aerial.scm

@@ -1,6 +1,5 @@
-(function_definition
-  declarator: (function_declarator
-    declarator: [(identifier) (field_identifier) (qualified_identifier)] @name)) @type
+(function_declarator
+  declarator: [(identifier) (field_identifier) (qualified_identifier)] @name) @type
 
 (struct_specifier
   name: (type_identifier) @name

tests/treesitter/c_spec.lua

@@ -8,41 +8,48 @@ describe("treesitter c", function()
         name = "fn_1",
         level = 0,
         lnum = 3,
-        col = 0,
+        col = 5,
       },
       {
         kind = "Function",
         name = "fn_2",
         level = 0,
         lnum = 5,
-        col = 0,
+        col = 6,
       },
       {
         kind = "Function",
         name = "fn_3",
         level = 0,
         lnum = 7,
-        col = 0,
+        col = 5,
       },
       {
         kind = "Function",
         name = "fn_4",
         level = 0,
         lnum = 9,
-        col = 0,
+        col = 6,
+      },
+      {
+        kind = "Function",
+        name = "fn_5",
+        level = 0,
+        lnum = 11,
+        col = 7,
       },
       {
         kind = "Enum",
         name = "kEnum",
         level = 0,
-        lnum = 11,
+        lnum = 13,
         col = 0,
       },
       {
         kind = "Struct",
         name = "St_1",
         level = 0,
-        lnum = 15,
+        lnum = 17,
         col = 0,
       },
     })

tests/treesitter/c_test.c

@@ -8,6 +8,8 @@ void fn_3() {}
 
 void *fn_4() { return 0; }
 
+void **fn_5() { return 0; }
+
 typedef enum {
   kVal,
 } kEnum;

tests/treesitter/cpp_spec.lua

@@ -8,7 +8,7 @@ describe("treesitter cpp", function()
         name = "fn_1",
         level = 0,
         lnum = 1,
-        col = 0,
+        col = 5,
       },
       {
         kind = "Struct",
@@ -43,7 +43,7 @@ describe("treesitter cpp", function()
             name = "meth_1",
             level = 1,
             lnum = 12,
-            col = 2,
+            col = 7,
           },
         },
       },
@@ -52,7 +52,21 @@ describe("treesitter cpp", function()
         name = "A::bar",
         level = 0,
         lnum = 15,
-        col = 0,
+        col = 5,
+      },
+      {
+        kind = "Function",
+        name = "fn_2",
+        level = 0,
+        lnum = 17,
+        col = 5,
+      },
+      {
+        kind = "Function",
+        name = "fn_3",
+        level = 0,
+        lnum = 19,
+        col = 6,
       },
     })
   end)

tests/treesitter/cpp_test.cpp

@@ -13,3 +13,7 @@ public:
 };
 
 void A::bar() {}
+
+int *fn_2() {}
+
+int **fn_3() {}