[iOliverC]

Hey,

I am making a text editor and would like to add a feature similar to SubEthaEdit. This feature is the Shift Left and Shift Right feature.

Basically, I can shift right easily (it seems to work perfectly) here is my code:

Code:
- (void)shiftRight:(id)sender;
{
	NSRange where = [docTextView selectedRange];
	NSString *selectedString = [[[docTextView textStorage] string] substringWithRange:where];
	NSArray *lines = [selectedString componentsSeparatedByString:@"\n"];
	
	if (![selectedString isEqualToString:@""])
	{
		NSMutableString *newString = [[NSMutableString alloc] init];
		int i;
		for (i=0;i<[lines count];i++)
		{
			NSString *lineString = [NSString stringWithFormat:@"\t%@", [lines objectAtIndex:i]];
			[newString appendString:lineString];
		}
		[docTextView replaceCharactersInRange:where withString:newString];
		[docTextView setSelectedRange:NSMakeRange(where.location, [newString length])];
	}
}

But I am having trouble figuring out how I can shift text left, a tab at a time. So basically, this is how it should work, the user highlights some text, clicks the shift left item, the code looks for a tab in the code, and if found deletes one (and only one). The problem I am having, is isolating one tab incase there are many tabs, and deleting one at a time.

Any ideas appreciated,
Oliver

[Wevah]

You could try checking to see whether the first character in a line is a tab, and then delete the first character if it is a tab.

Maybe?

[hayesk]

I agree with Wevah. Do it line by line basis, not character by character basis. Check char, if tab, delete - then search for next line , not character, and repeat.

[iOliverC]

Right,

I got it to semi-work, but I am having a little problem:

Code:
- (void)shiftLeft:(id)sender;
{
	NSRange where = [docTextView selectedRange];
	NSString *selectedString = [[[docTextView textStorage] string] substringWithRange:where];
	NSArray *lines = [selectedString componentsSeparatedByString:@"\n"];
	NSMutableString *newString = [[NSMutableString alloc] init];
	
	if (![selectedString isEqualToString:@""])
	{
		int i;
		for (i=0;i<[lines count];i++)
		{
			NSString *lineString = [NSString stringWithFormat:@"%@", [lines objectAtIndex:i]];
			if ([lineString length] > 0 && [lineString characterAtIndex:0] == '\t')
			{
				lineString = [lineString substringFromIndex:1];
			}
			[newString appendString:lineString];
			if (i!=[lines count]-1)
				[newString appendString:@"\n"];
		}
		[docTextView replaceCharactersInRange:where withString:newString];
		[docTextView setSelectedRange:NSMakeRange(where.location, [newString length])];
	}
}

So if for example I have some code that looks like this:

*Tab*Hello

It moves Hello right to the left.

But I am having a problem with some webpages that have code like:

*Space**Tab**Tab*Hello

This basically means my code won't function at all correctly. Since a space is the first char. Anyone got any ideas?

Thanks,
Oliver

[Wevah]

You could use [NSCharacterSet whitespaceCharacterSet] with NSString's rangeOfCharacterFromSet:

Or, you could possibly do:

if ([lineString length] > 0 && ([lineString characterAtIndex:0] == '\t' || [lineString characerAtIndex:0] == ' '))

[iOliverC]

Originally posted by Wevah:
You could use [NSCharacterSet whitespaceCharacterSet] with NSString's rangeOfCharacterFromSet:

Or, you could possibly do:

if ([lineString length] > 0 && ([lineString characterAtIndex:0] == '\t' || [lineString characerAtIndex:0] == ' '))

I ended up using your bottom method, thanks.

Oliver