Difference between revisions of "Talk:for-in loop"

From Free Pascal wiki
Jump to navigationJump to search
m (Fixed syntax highlighting)
Line 6: Line 6:
 
== Multiple enumerators for one class ==
 
== Multiple enumerators for one class ==
  
The underlying code causes a memory leak
+
The underlying code causes a memory leak:
<syntaxhighlight>
+
 
 +
<syntaxhighlight lang=pascal>
 
function TEnumerableTree.GetReverseEnumerator: TTreeReverseEnumerator;
 
function TEnumerableTree.GetReverseEnumerator: TTreeReverseEnumerator;
 
begin
 
begin
Line 14: Line 15:
 
</syntaxhighlight>
 
</syntaxhighlight>
  
object created, but not destroed
+
object created, but not destroyed

Revision as of 01:20, 16 February 2020

Proposed extensions - Select which enumerator to use

Why so complicated syntax and new keyword using? Why do not just always use syntax like for x in <IEnumeratorExpression> do ...;, as described in Variant3 and Variant4? In this case no need to introduce any FPC-specific operator (or just to describe default enumerator, to make text shorter?..), no need 'enumerator MoveNext' and 'enumerator Current' modifiers, because interface implementation already can be mapped to other methods... --Nashev 18:43, 12 September 2011 (CEST)

Proposed extensions - index

May be more pretty will python or php-like syntax for ch[i] in s do Writeln(i, ': ', ch); (see http://www.php2python.com/wiki/control-structures.foreach/ for reference) --Nashev 18:43, 12 September 2011 (CEST)

Multiple enumerators for one class

The underlying code causes a memory leak:

function TEnumerableTree.GetReverseEnumerator: TTreeReverseEnumerator;
begin
  Result:=TTreeReverseEnumerator.Create(Self);
end;

object created, but not destroyed