Generic API: bind the Lookup function for nodes

langkit/support/langkit_support-generic_api-analysis.adb

@@ -1149,6 +1149,22 @@ package body Langkit_Support.Generic_API.Analysis is
       return Self.Desc.Node_Sloc_Range (Self.Internal.Node);
    end Sloc_Range;
 
+   ------------
+   -- Lookup --
+   ------------
+
+   function Lookup
+     (Self : Lk_Node'Class; Sloc : Source_Location) return Lk_Node is
+   begin
+      Check_Safety_Net (Self);
+      if Self.Is_Null then
+         return No_Lk_Node;
+      end if;
+
+      return Wrap_Node
+               (Self.Desc.Node_Lookup (Self.Internal.Node, Sloc), Self);
+   end Lookup;
+
    -------------------
    -- Is_Incomplete --
    -------------------

langkit/support/langkit_support-generic_api-analysis.ads

@@ -333,6 +333,12 @@ package Langkit_Support.Generic_API.Analysis is
    --
    --  Note that this returns the sloc of the parent for synthetic nodes.
 
+   function Lookup
+     (Self : Lk_Node'Class; Sloc : Source_Location) return Lk_Node;
+   --  Look for the bottom-most node in the ``Self`` subtree whose sloc range
+   --  contains ``Sloc``. Return it, or ``No_Lk_Node`` if no such node was
+   --  found.
+
    --  TODO??? Bind all other node primitives
 
    function Is_Incomplete (Self : Lk_Node) return Boolean;

langkit/support/langkit_support-internal-descriptor.ads

@@ -109,6 +109,9 @@ package Langkit_Support.Internal.Descriptor is
      (Node : Analysis.Internal_Node) return Text_Type;
    type Node_Sloc_Range_Type is access function
      (Node : Analysis.Internal_Node) return Source_Location_Range;
+   type Node_Lookup_Type is access function
+     (Node : Analysis.Internal_Node;
+      Sloc : Source_Location) return Analysis.Internal_Node;
    type Node_Last_Attempted_Child_Type is access function
      (Node : Analysis.Internal_Node) return Integer;
 
@@ -217,6 +220,7 @@ package Langkit_Support.Internal.Descriptor is
       Node_Token_End            : Node_Token_Getter_Type;
       Node_Text                 : Node_Text_Type;
       Node_Sloc_Range           : Node_Sloc_Range_Type;
+      Node_Lookup               : Node_Lookup_Type;
       Node_Last_Attempted_Child : Node_Last_Attempted_Child_Type;
 
       Entity_Image : Entity_Image_Type;

langkit/templates/pkg_generic_impl_body_ada.mako

@@ -465,6 +465,17 @@ package body ${ada_lib_name}.Generic_Impl is
       return Implementation.Sloc_Range (+Node);
    end Node_Sloc_Range;
 
+   -----------------
+   -- Node_Lookup --
+   -----------------
+
+   function Node_Lookup
+     (Node : Analysis.Internal_Node;
+      Sloc : Source_Location) return Analysis.Internal_Node is
+   begin
+      return +Implementation.Lookup (+Node, Sloc);
+   end Node_Lookup;
+
    -------------------------------
    -- Node_Last_Attempted_Child --
    -------------------------------

langkit/templates/pkg_generic_impl_spec_ada.mako

@@ -180,6 +180,9 @@ private package ${ada_lib_name}.Generic_Impl is
    function Node_Text (Node : Internal_Node) return Text_Type;
    function Node_Sloc_Range
      (Node : Internal_Node) return Source_Location_Range;
+   function Node_Lookup
+     (Node : Analysis.Internal_Node;
+      Sloc : Source_Location) return Analysis.Internal_Node;
    function Node_Last_Attempted_Child (Node : Internal_Node) return Integer;
 
    function Entity_Image (Entity : Internal_Entity) return String;
@@ -267,6 +270,7 @@ private package ${ada_lib_name}.Generic_Impl is
       Node_Token_End            => Node_Token_End'Access,
       Node_Text                 => Node_Text'Access,
       Node_Sloc_Range           => Node_Sloc_Range'Access,
+      Node_Lookup               => Node_Lookup'Access,
       Node_Last_Attempted_Child => Node_Last_Attempted_Child'Access,
 
       Entity_Image => Entity_Image'Access,

testsuite/tests/ada_api/generic_api/analysis.adb

@@ -330,6 +330,11 @@ begin
    end;
    New_Line;
 
+   Put_Line
+     ("No_Lk_Node.Lookup (1, 1) -> " & Image (No_Lk_Node.Lookup ((1, 1))));
+   Put_Line ("Root.Lookup (2, 7) -> " & Image (U.Root.Lookup ((2, 7))));
+   New_Line;
+
    Put_Line ("Root.Is_Incomplete -> " & U.Root.Is_Incomplete'Image);
    Put ("No_Lk_Node.Is_Incomplete -> ");
    declare

testsuite/tests/ada_api/generic_api/test.out

@@ -151,6 +151,9 @@ No_Lk_Node.Text -> Got a Precondition_Failure exception: null node
 Root.Sloc_Range -> 1:1-3:15
 No_Lk_Node.Sloc_Range -> Got a Precondition_Failure exception: null node
 
+No_Lk_Node.Lookup (1, 1) -> None
+Root.Lookup (2, 7) -> <VarDecl example.txt:2:1-2:11>
+
 Root.Is_Incomplete -> FALSE
 No_Lk_Node.Is_Incomplete -> Got a Precondition_Failure exception: null node