From: Rob Pike <r@golang.org>
Date: Tue, 2 Sep 2008 20:16:43 +0000 (-0700)
Subject: vector cleanup:
X-Git-Tag: weekly.2009-11-06~3294
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=a0b2ccf9f49bbd4171a047ac60b16f7d92a1d60a;p=gostls13.git

vector cleanup:
- change Delete to Remove
- return deleted element in Remove
- remove range checking (runtime does this for you)

R=gri
OCL=14714
CL=14714
---

diff --git a/src/lib/container/vector.go b/src/lib/container/vector.go
index 058992c0ba..72a0fff742 100644
--- a/src/lib/container/vector.go
+++ b/src/lib/container/vector.go
@@ -11,7 +11,7 @@ package vector
 	v := vector.New();
 	v.Insert(0, new(Foo));
 	v.Append(new(Foo));
-	v.Delete(0);
+	v.Remove(0);
 	for i := 0; i < v.Len(); i++ { f(v.At(i)); }
 */
 
@@ -26,56 +26,39 @@ export type Vector struct {
 
 export func New() *Vector {
 	v := new(Vector);
-	v.elem = new([]Element, 1) [0 : 0];  // capacity must be > 0!
+	v.elem = new([]Element, 8) [0 : 0];  // capacity must be > 0!
 	return v;
 }
 
 
-func (v *Vector) RangeError(op string, i int) {
-	panic("Vector.", op, ": index ", i, " out of range (len = ", len(v.elem), ")\n");
-}
-
-
 func (v *Vector) Len() int {
 	return len(v.elem);
 }
 
 
 func (v *Vector) At(i int) Element {
-	n := v.Len();
-	if i < 0 || i >= n {
-		v.RangeError("At", i);
-		var e Element;
-		return e;  // don't return nil - may not be legal in the future
-	}
+	// range check unnecessary - done by runtime
 	return v.elem[i];
 }
 
 
-// TODO(r) It would be better if this were called 'Remove' and if
-// it were returning the removed element. This way it would be 
-// symmetric with 'Insert', provide the functionality of 'Delete'
-// and allow to get the appropriate entry w/ an extra call.
-
-func (v *Vector) Delete(i int) {
+func (v *Vector) Remove(i int) Element {
+	ret := v.elem[i];
 	n := v.Len();
-	if i < 0 || i >= n {
-		v.RangeError("Delete", i);
-	}
+	// range check unnecessary - done by runtime
 	for j := i + 1; j < n; j++ {
 		v.elem[j - 1] = v.elem[j];
 	}
 	var e Element;
 	v.elem[n - 1] = e;  // don't set to nil - may not be legal in the future
 	v.elem = v.elem[0 : n - 1];
+	return ret;
 }
 
 
 func (v *Vector) Insert(i int, e Element) {
 	n := v.Len();
-	if i < 0 || i > n {
-		v.RangeError("Insert", i);
-	}
+	// range check unnecessary - done by runtime
 
 	// grow array by doubling its capacity
 	if n == cap(v.elem) {
diff --git a/test/vectors.go b/test/vectors.go
index d6a2015fee..93280f42ce 100644
--- a/test/vectors.go
+++ b/test/vectors.go
@@ -50,7 +50,7 @@ func test1() {
 	}
 	
 	for v.Len() > 10 {
-		v.Delete(10);
+		v.Remove(10);
 	}
 }