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digitalmars.D.learn - Changing the size of an foreach() argument

reply AEon <aeon2001 lycos.de> writes:
On writing a simple function that will expand command line wildcards 
(using std.recls, once I figure that out), I have come accross a 
situation where the list of command line arguments  char[][] args as 
defined in main() must change:


void expand_Wildcard( char[][] args )
{
	char[][] tArgs = args.dup;
	int found = 0;

	foreach(int i, char[] file; args )
	{
		...

		args.length = 2; 	// Error vs. foreach
	}		
	etc
}


In the foreach loop I would check every args / "file" and check it for a 
wildcard. Now should "file" actually contain a *, the args.length would 
need change.

To make this work, I would need to make a duplicate (not a reference) via:

	char[][] tArgs = args.dup;

Question is, is this correct?

IIRC tArgs would actually be a "reference" to args, meaning, should I 
change anything in tArgs, this would also change args?

AEon
Apr 07 2005
parent "Ben Hinkle" <bhinkle mathworks.com> writes:
 To make this work, I would need to make a duplicate (not a reference) via:

 char[][] tArgs = args.dup;

 Question is, is this correct?

 IIRC tArgs would actually be a "reference" to args, meaning, should I 
 change anything in tArgs, this would also change args?

 AEon

Even with the .dup you are still changing the array inside of the foreach. I suggest building up the expanded array inside the foreach over args: void expand_Wildcard( char[][] args ) { char[][] expandedArgs; int found = 0; foreach(char[] file; args ) { if (needsExpansion(file)) { char[][] expandedArg = expand(file); expandedArgs ~= expandedArg; } else { expandedArgs ~= file; } } }
Apr 07 2005