From ddb7278760029be9d960ba8bf2b06ac8a8aac767 Mon Sep 17 00:00:00 2001
From: Andrew Waterman
Date: Mon, 15 Aug 2016 22:48:14 -0700
Subject: Make "def width" a private API; expose isWidthKnown instead (#257)

* Make "def width" a private API; expose isWidthKnown instead

Resolves #256.

Since width was used to determine whether getWidth would succeed, I added

    def isWidthKnown: Boolean

but another option would be to expose something like

    def widthOption: Option[Int]

...thoughts?

* Document getWidth/isWidthKnown

* Add widthOption for more idiomatic Scala manipulation of widths
---
 chiselFrontend/src/main/scala/chisel3/core/Data.scala | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

(limited to 'chiselFrontend/src/main/scala/chisel3/core/Data.scala')

diff --git a/chiselFrontend/src/main/scala/chisel3/core/Data.scala b/chiselFrontend/src/main/scala/chisel3/core/Data.scala
index d31e50ff..8826af51 100644
--- a/chiselFrontend/src/main/scala/chisel3/core/Data.scala
+++ b/chiselFrontend/src/main/scala/chisel3/core/Data.scala
@@ -56,6 +56,7 @@ abstract class Data(dirArg: Direction) extends HasId {
   private[chisel3] def ref: Arg = if (isLit) litArg.get else lref
   private[core] def cloneTypeWidth(width: Width): this.type
   private[chisel3] def toType: String
+  private[core] def width: Width
 
   def := (that: Data)(implicit sourceInfo: SourceInfo): Unit = this badConnect that
 
@@ -66,8 +67,13 @@ abstract class Data(dirArg: Direction) extends HasId {
   def litValue(): BigInt = litArg.get.num
   def isLit(): Boolean = litArg.isDefined
 
-  def width: Width
+  /** Returns the width, in bits, if currently known.
+    * @throws java.util.NoSuchElementException if the width is not known. */
   final def getWidth: Int = width.get
+  /** Returns whether the width is currently known. */
+  final def isWidthKnown: Boolean = width.known
+  /** Returns Some(width) if the width is known, else None. */
+  final def widthOption: Option[Int] = if (isWidthKnown) Some(getWidth) else None
 
   // While this being in the Data API doesn't really make sense (should be in
   // Aggregate, right?) this is because of an implementation limitation:
-- 
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