From 9eee1175d9c3089ba53ebed12171bf57a40e80e3 Mon Sep 17 00:00:00 2001
From: Tim Foley <tfoley@nvidia.com>
Date: Tue, 27 Jun 2017 14:22:01 -0700
Subject: Allow "dotted" import paths

The code:

    __import foo.bar;

will try to import from a file matching "foo/bar.slang".

I also went ahead and allowed a raw string literal in and import:

    __import "foo/bar";

(In the latter case, an explicit `/` must be used instead of `.`)
---
 source/slang/parser.cpp                      | 38 +++++++++++++++++++++++-----
 tests/front-end/import-subdir.slang          |  7 +++++
 tests/front-end/subdir/import-subdir-a.slang |  5 ++++
 3 files changed, 44 insertions(+), 6 deletions(-)
 create mode 100644 tests/front-end/import-subdir.slang
 create mode 100644 tests/front-end/subdir/import-subdir-a.slang

diff --git a/source/slang/parser.cpp b/source/slang/parser.cpp
index 1d843c821..3ffbc1263 100644
--- a/source/slang/parser.cpp
+++ b/source/slang/parser.cpp
@@ -794,15 +794,46 @@ namespace Slang
         }
     }
 
+    static TokenType peekTokenType(Parser* parser)
+    {
+        return parser->tokenReader.PeekTokenType();
+    }
+
     static RefPtr<Decl> parseImportDecl(
         Parser* parser)
     {
         parser->ReadToken("__import");
 
         auto decl = new ImportDecl();
-        decl->nameToken = parser->ReadToken(TokenType::Identifier);
         decl->scope = parser->currentScope;
 
+        if (peekTokenType(parser) == TokenType::StringLiterial)
+        {
+            auto nameToken = parser->ReadToken(TokenType::StringLiterial);
+            nameToken.Content = getStringLiteralTokenValue(nameToken);
+            decl->nameToken = nameToken;
+        }
+        else
+        {
+            auto nameToken = parser->ReadToken(TokenType::Identifier);
+
+            // We allow a dotted format for the name, as sugar
+            if (peekTokenType(parser) == TokenType::Dot)
+            {
+                StringBuilder sb;
+                sb << nameToken.Content;
+                while (AdvanceIf(parser, TokenType::Dot))
+                {
+                    sb << "/";
+                    sb << parser->ReadToken(TokenType::Identifier).Content;
+                }
+
+                nameToken.Content = sb.ProduceString();
+            }
+
+            decl->nameToken = nameToken;
+        }
+
         parser->ReadToken(TokenType::Semicolon);
 
         return decl;
@@ -3093,11 +3124,6 @@ namespace Slang
 #endif
     }
 
-    static TokenType peekTokenType(Parser* parser)
-    {
-        return parser->tokenReader.PeekTokenType();
-    }
-
     // We *might* be looking at an application of a generic to arguments,
     // but we need to disambiguate to make sure.
     static RefPtr<ExpressionSyntaxNode> maybeParseGenericApp(
diff --git a/tests/front-end/import-subdir.slang b/tests/front-end/import-subdir.slang
new file mode 100644
index 000000000..0d3931a82
--- /dev/null
+++ b/tests/front-end/import-subdir.slang
@@ -0,0 +1,7 @@
+//TEST:SIMPLE:
+
+// Confirming that we can use "dot notation" to import via a subdirectory
+
+__import subdir.import_subdir_a;
+
+float bar(float x) { return foo(x); }
\ No newline at end of file
diff --git a/tests/front-end/subdir/import-subdir-a.slang b/tests/front-end/subdir/import-subdir-a.slang
new file mode 100644
index 000000000..3962d4662
--- /dev/null
+++ b/tests/front-end/subdir/import-subdir-a.slang
@@ -0,0 +1,5 @@
+//TEST_IGNORE_FILE:
+
+// This is the imported code.
+
+float foo(float x) { return x; }
\ No newline at end of file
-- 
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