From 6fe52d95b35b56d84cd063aee5b73310bb16a371 Mon Sep 17 00:00:00 2001
From: Alexandros Naskos <alex_naskos@hotmail.com>
Date: Tue, 19 May 2020 18:53:01 +0300
Subject: [PATCH] Added @This() support

---
 src/analysis.zig       | 20 +++++++++++++++++---
 src/document_store.zig | 14 ++++++++++++++
 2 files changed, 31 insertions(+), 3 deletions(-)

diff --git a/src/analysis.zig b/src/analysis.zig
index c9f6e8b..9a19487 100644
--- a/src/analysis.zig
+++ b/src/analysis.zig
@@ -263,7 +263,10 @@ fn resolveReturnType(analysis_ctx: *AnalysisContext, fn_decl: *ast.Node.FnProto)
         // a container declaration, we will return that declaration.
         const ret = findReturnStatement(fn_decl.body_node.?) orelse return null; 
         if (ret.rhs) |rhs| if (resolveTypeOfNode(analysis_ctx, rhs)) |res_rhs| switch(res_rhs.id) {
-            .ContainerDecl => return res_rhs,
+            .ContainerDecl => {
+                analysis_ctx.onContainer(res_rhs.cast(ast.Node.ContainerDecl).?) catch return null;
+                return res_rhs;
+            },
             else => return null,
         };
 
@@ -295,6 +298,7 @@ pub fn resolveTypeOfNode(analysis_ctx: *AnalysisContext, node: *ast.Node) ?*ast.
         },
         .Identifier => {
             if (getChildOfSlice(analysis_ctx.tree, analysis_ctx.scope_nodes, analysis_ctx.tree.getNodeSource(node))) |child| {
+                std.debug.warn("Found node {}\n", .{child});
                 return resolveTypeOfNode(analysis_ctx, child);
             } else return null;
         },
@@ -347,7 +351,13 @@ pub fn resolveTypeOfNode(analysis_ctx: *AnalysisContext, node: *ast.Node) ?*ast.
         },
         .BuiltinCall => {
             const builtin_call = node.cast(ast.Node.BuiltinCall).?;
-            if (!std.mem.eql(u8, analysis_ctx.tree.tokenSlice(builtin_call.builtin_token), "@import")) return null;
+            const call_name = analysis_ctx.tree.tokenSlice(builtin_call.builtin_token);
+            if (std.mem.eql(u8, call_name, "@This")) {
+                if (builtin_call.params.len != 0) return null;
+                return analysis_ctx.last_this_node;
+            }
+            
+            if (!std.mem.eql(u8, call_name, "@import")) return null;
             if (builtin_call.params.len > 1) return null;
 
             const import_param = builtin_call.params.at(0).*;
@@ -359,7 +369,11 @@ pub fn resolveTypeOfNode(analysis_ctx: *AnalysisContext, node: *ast.Node) ?*ast.
                 break :block null;
             };
         },
-        .MultilineStringLiteral, .StringLiteral, .ContainerDecl, .ErrorSetDecl, .FnProto => return node,
+        .ContainerDecl => {
+            analysis_ctx.onContainer(node.cast(ast.Node.ContainerDecl).?) catch return null;
+            return node;
+        },
+        .MultilineStringLiteral, .StringLiteral, .ErrorSetDecl, .FnProto => return node,
         else => std.debug.warn("Type resolution case not implemented; {}\n", .{node.id}),
     }
     return null;
diff --git a/src/document_store.zig b/src/document_store.zig
index 084968c..c42459f 100644
--- a/src/document_store.zig
+++ b/src/document_store.zig
@@ -258,11 +258,13 @@ pub const AnalysisContext = struct {
     arena: *std.heap.ArenaAllocator,
     tree: *std.zig.ast.Tree,
     scope_nodes: []*std.zig.ast.Node,
+    last_this_node: *std.zig.ast.Node,
 
     fn refreshScopeNodes(self: *AnalysisContext) !void {
         var scope_nodes = std.ArrayList(*std.zig.ast.Node).init(&self.arena.allocator);
         try analysis.addChildrenNodes(&scope_nodes, self.tree, &self.tree.root_node.base);
         self.scope_nodes = scope_nodes.items;
+        self.last_this_node = &self.tree.root_node.base;
     }
 
     pub fn onImport(self: *AnalysisContext, import_str: []const u8) !?*std.zig.ast.Node {
@@ -348,9 +350,20 @@ pub const AnalysisContext = struct {
             .arena = self.arena,
             .tree = tree,
             .scope_nodes = self.scope_nodes,
+            .last_this_node = &tree.root_node.base,
         };
     }
 
+    pub fn onContainer(self: *AnalysisContext, container: *std.zig.ast.Node.ContainerDecl) !void {
+        if (self.last_this_node != &container.base) {
+            self.last_this_node = &container.base;
+
+            var scope_nodes = std.ArrayList(*std.zig.ast.Node).init(&self.arena.allocator);
+            try analysis.addChildrenNodes(&scope_nodes, self.tree, &container.base);
+            self.scope_nodes = scope_nodes.items;
+        }
+    }
+
     pub fn deinit(self: *AnalysisContext) void {
         self.tree.deinit();
     }
@@ -368,6 +381,7 @@ pub fn analysisContext(self: *DocumentStore, handle: *Handle, arena: *std.heap.A
         .arena = arena,
         .tree = tree,
         .scope_nodes = scope_nodes.items,
+        .last_this_node = &tree.root_node.base,
     };
 }