Add utilities

After a refactoring of utilities, I added a function to get the first
child node that matches the node name.

Documentation is provided in neogen.utilities.nodes

lua/neogen/utilities/extractors.lua

@@ -0,0 +1,51 @@
+local ts_utils = require("nvim-treesitter.ts_utils")
+
+neogen.utilities.extractors = {
+    --- Return a function to extract content of required children from a node
+    --- @param _ any self
+    --- @param name string the children we want to extract (if multiple childrens, separate each one with "|")
+    --- @return function cb function taking a node and getting the content of each children we want from name
+    extract_children_text = function(_, name)
+        return function(node)
+            local result = {}
+            local split = vim.split(name, "|", true)
+
+
+            for child in node:iter_children() do
+                if vim.tbl_contains(split, child:type()) then
+                    table.insert(result, ts_utils.get_node_text(child)[1])
+                end
+            end
+
+            return result
+        end
+    end,
+
+    --- Extract content from specified children from a tree
+    --- the tree parameter can be a nested { [key] = value} with key being the
+    --- * key: is which children we want to extract the values from (e.g first children is 1)
+    --- * value: "extract" or { [key] = value }. If value is "extract", it will extract the key child node
+    --- Example (extract the first child node from the first child node of the parent node):
+    --- [1] = {
+    ---  [1] = "extract"
+    --- }
+    --- @param tree table see description
+    --- @param name string the children we want to extract (if multiple children, separate each one with "|")
+    extract_children_from = function(self, tree, name)
+        return function(node)
+            local result = {}
+
+            for i, subtree in pairs(tree) do
+                local child_node = node:named_child(tonumber(i) - 1)
+
+                if subtree == "extract" then
+                    return self:extract_children_text(name)(child_node)
+                else
+                    return self:extract_children_from(subtree, name)(child_node)
+                end
+            end
+
+            return result
+        end
+    end,
+}

lua/neogen/utilities/nodes.lua

@@ -0,0 +1,14 @@
+neogen.utilities.nodes = {
+    --- Get first child node that match the provided node name
+    --- @param _ any
+    --- @param parent userdata the parent's node
+    --- @param node_name string the node type to search for
+    --- @return userdata node the first encountered child node
+    first_child_node = function (_, parent, node_name)
+        for child in parent:iter_children() do
+            if child:type() == node_name then
+                return child
+            end
+        end
+    end
+}