Update user guilde for new features. (#3875)

1 files changed, 50 insertions, 1 deletions

diff --git a/docs/user-guide/02-conventional-features.md b/docs/user-guide/02-conventional-features.md
index 8c45fec48..be931d5cd 100644
--- a/docs/user-guide/02-conventional-features.md
+++ b/docs/user-guide/02-conventional-features.md
@@ -160,7 +160,7 @@ enum Channel
 
 Unlike C/C++, `enum` types in Slang are always scoped by default (like `enum class` in C++). You can write `enum class` in Slang if it makes you happy, but it isn't required. If you want a `enum` type to be unscoped, you can use the `[UnscopedEnum]` attribute:
 ```csharp
-[[UnscopedEnum]
+[UnscopedEnum]
 enum Channel
 {
     Red, Green, Blue
@@ -171,6 +171,47 @@ void test(Channel c)
 }
 ```
 
+You can specify an explicit underlying integer type for `enum` types:
+```csharp
+enum Channel : uint16_t
+{
+    Red, Green, Blue
+}
+```
+
+By default, the underlying type of an enumeration type is `int`. Enumeration types are implicitly convertible to its underlying type. All enumeration types conform to the builtin `ILogical` interface, which provides operator overloads for bit operations. The following code is allowed:
+
+```csharp
+void test()
+{
+    Channel c = Channel.Red | Channel.Green;
+}
+```
+
+You can explicitly assign values to each enum case:
+```csharp
+enum Channel
+{
+    Red = 5,
+    Green,   // = 6
+    Blue     // = 7
+}
+```
+Slang automatically assigns integer values to enum cases without an explicit value. By default, the value starts from 0 and is increment by 1 for each
+enum case.
+
+You can override the implicit value assignment behavior with the `[Flags]` attribute, which will make value assignment start from 1 and increment by power of 2, making it suitable for enums that represent bit flags. For example:
+```csharp
+[Flags]
+enum Channel
+{
+    Red,   //  = 1
+    Green, //  = 2
+    Blue,  //  = 4
+    Alpha, //  = 8
+}
+```
+
 ### Opaque Types
 
 The Slang standard library defines a large number of _opaque_ types which provide access to objects that are allocated via GPU APIs.
@@ -352,6 +393,14 @@ float addSomeThings(int x, float y)
 }
 ```
 
+In addition to the traditional C syntax, you can use the modern syntax to define functions with the `func` keyword:
+```swift
+func addSomeThings(x : int, y : float) -> float
+{
+    return x + y;
+}
+```
+
 Slang supports overloading of functions based on parameter types.
 
 Function parameters may be marked with a _direction_ qualifier: