TweetFollow Us on Twitter

Jan 02 MacOSX

Volume Number: 18 (2002)
Issue Number: 01
Column Tag: Mac OS X

Smart Quotes

by ©2001 Andrew C. Stone. All Rights Reserved.

Adding automated curly quotes to Cocoa's Text system

Cocoa's Text System architecture is open, open-ended, and contains hooks for easy behavior modification. Because Cocoa Text is a unicode based system, it is by default international and lets your applications work correctly in a variety of scripts and languages. This article will teach you how to inspect the user's typed stream of keys, and convert straight quotes to open and closed curly quotes as the user types:

"Love is ‘THE' answer," she said.

Remembering all the modifier keys to create a curly quote is troublesome for end users, so we'll add the functionality to replace the boring straight quotes with fancy curly ones as they type. We'll also include a mechanism to "toggle through" the various options for those odd border cases, such as words beginning with a quote: 'Tis.

The Unicode

Cocoa's Text system relies on Unicode which allows each character in most standard font to be mapped to a unique short integer, a "unichar" defined in NSString.h:

typedef unsigned short unichar;

For example, each glyph in the Symbol font and Dingbats font are represented by unicode characters. The HTML standard also allows use of unicode characters, and here are the Unicode and HTML codes (which correspond to the unicode value) for curly quotes:

Character Unicode HTML Name How to type in manually
" 8220 “ double open quote Option-[
' 8216 ‘ single open quote Option-]
" 8221 ” double close Option-Shift-[
' 8217 ’ single close Option-Shift-]

Now that we know what will replace the straight quotes, we need a strategy for determining if a quote should be open or closed! It turns out that a very simple heuristic will work:

if character typed is a Straight Quote then

If it's the first character or is preceded by whitespace, turn it into Open Curly Quote

       else turn it into Close Curly Quote

So, when a newline, tab or space precedes a quote, it's probably an open quote. Note that this fails with ‘Tis! So, let's refine our heuristic to include a mechanism to "move through" the options straight, open and closed if the user has the quote in question solely selected:

if character typed is ‘ or " then

if selection contains a  single quote of any style,  replace with the next style in a loop (straight -> 
open -> closed -> straight and so on)

    else

If it's the first character or is preceded by whitespace, turn into Open Quote (single or double)

       else turn it into Close Quote

We have one more feature to add - the user should be able to DIRECTLY type in a straight quote when fancy quotes are enabled. We'll let them do this by changing any typed fancy quote to its straight counterpart (see How to type in manually in table above).

The Hook

One aspect of Cocoa that reigns supreme is the ease in which functionality can added, as well as the many different approaches that can be taken to accomplish the same task.

Where you put code depends on your architectural design. While you can always override a class, it's often easier to simply look at the "Delegate Methods" defined in various classes. These methods are optional: if an object, such as a text view, has a delegate, and that delegate implements one of these methods, then that method will be called at the appropriate time by the text view. If you overrode "keyDown" in NSTextView in a subclass, your text wouldn't swap the quotes on pasted text, since pasting does not call keyDown! So, instead we'll use this NSTextView delegate method that gets called anytime text is inserted either via keys or paste:

- (BOOL)textView:(NSTextView *)textView shouldChangeTextInRange:(NSRange)affectedCharRange 
replacementString:(NSString *)replacementString;

    // Delegate only.  If characters are changing, replacementString is what will replace the 
    affectedCharRange.  If attributes only are changing, replacementString will be nil.

This delegate method will work for us since we are only replacing single characters with another single character. If I had designed this method, instead of returning a boolean, I would have had this method return the actual new string to be inserted. Working with the method the way it is, we'll simply brute force stick in the character of our choice and return NO.

The Code

// Code is always more readable if you can turn the magic numbers into English!
#define SINGLE_QUOTE      ‘\''
#define SINGLE_OPEN_QUOTE   8216
#define SINGLE_CLOSE_QUOTE   8217
#define DOUBLE_QUOTE      ‘"‘
#define DOUBLE_OPEN_QUOTE   8220
#define DOUBLE_CLOSE_QUOTE   8221

// Smart Quote support - in our NSTextView's delegate class, we implement this method
// Be sure to connect the TextView's delegate outlet to your custom delegate class in Interface Builder
// or use  [myTextView setDelegate:self]; in your delegate class so this gets called:

- (BOOL)textView:(NSTextView *)textView shouldChangeTextInRange:(NSRange)affectedCharRange 
replacementString:(NSString *)replacementString;

    // Delegate only.  If characters are changing, replacementString is what will replace the 
    affectedCharRange.  If attributes only are changing, replacementString will be nil.
{

   // if we're just changing text attributes then we don't enter our processing loop
   // Also, provide a defaults mechanism to turn this fancy quoting off:
   
    if (replacementString && [[NSUserDefaults standardUserDefaults]boolForKey:SmartQuotes]) {
    
       // This is what is in our text object before anything is added:
        NSString *text = [[textView textStorage] string];
   
      // We want to know if we are at the very first character:
        unsigned int textLength = [text length];
   
      // how much are  we actually adding at this time:
        unsigned int i, length = [replacementString length];
        unichar c;
   
      // Should we change the string, we'll use this mutable string to hold the new values:
      // If it's non-nil when we get done, that means we've got work to do!
        NSMutableString *s = nil;
            
       // First, our toggle through mechanism:
        // special case: one char typed OVER a smart quote -> toggle them around 3 way
        // plain -> open -> closed -> plain
        // First deal with the case where they want another type of quote or a plain quote!
        if (length == 1 &&  affectedCharRange.length == 1) {
   
            if (((c = [text characterAtIndex:affectedCharRange.location])==DOUBLE_OPEN_QUOTE) || 
            (c == SINGLE_OPEN_QUOTE)) {
                // they had an open quote -> make it a closed one
                s = [NSString stringWithFormat:@"%C", c == DOUBLE_OPEN_QUOTE ? 
                DOUBLE_CLOSE_QUOTE : SINGLE_CLOSE_QUOTE];
      
            } else if (c == DOUBLE_CLOSE_QUOTE || c == SINGLE_CLOSE_QUOTE) {
                // they had a closed quote -> make it plain
                s = [NSString stringWithFormat:@"%C", c == DOUBLE_CLOSE_QUOTE  ? 
                DOUBLE_QUOTE : SINGLE_QUOTE];
      
            } else if (c == SINGLE_QUOTE || c == DOUBLE_QUOTE) {
             // they had a straight quote -> make it open
                 s = [NSString stringWithFormat:@"%C", c == SINGLE_QUOTE  ?  
                 SINGLE_OPEN_QUOTE : DOUBLE_OPEN_QUOTE];
           }
        } else {
   
        // otherwise go through replacement string one by one - paste can put in many characters at 
        one time!
            NSCharacterSet *startSet = [NSCharacterSet whitespaceAndNewlineCharacterSet];
            for (i = 0; i < length; i++) {
       
                unichar theChar = [replacementString characterAtIndex:i];
                unichar previousChar;
                
            // Find out the character which preceeds this one - context is everything!
                if(i == 0) {
                    if (affectedCharRange.location == 0 || textLength==0) previousChar = 0; 
                    // first char
                    else previousChar = [text characterAtIndex:affectedCharRange.location - 1];
                } else previousChar = [replacementString characterAtIndex:i-1];
                
            // When we encounter a straight quote, we decide whether it should be open or closed:
                if ((theChar == SINGLE_QUOTE) || (theChar == DOUBLE_QUOTE)){
      
               // lazily allocate the mutable string if we find something interesting
                    if (!s) s = [NSMutableString stringWithString:replacementString]; 
                    
                    if (previousChar == 0 || [startSet characterIsMember:previousChar] || 
                    (previousChar == DOUBLE_OPEN_QUOTE && theChar == SINGLE_QUOTE) || 
                    (previousChar == SINGLE_OPEN_QUOTE && theChar == DOUBLE_QUOTE))
                        c =  (theChar  == SINGLE_QUOTE  ?  SINGLE_OPEN_QUOTE : DOUBLE_OPEN_QUOTE);
                    else c =  (theChar  == SINGLE_QUOTE  ?  SINGLE_CLOSE_QUOTE : DOUBLE_CLOSE_QUOTE);
                    
                    [s replaceCharactersInRange:NSMakeRange(i,1) 
                    withString:[NSString stringWithFormat:@"%C", c]];
          
                } else if ((i==0) && (length == 1)) {
      
                    // we don't want to do this unless they are typing - paste may contain curly's 
                    already!
                    // reverse the meaning - they want to type in a plain one from the keyboard 
                    directly:
          
                    if ((theChar == SINGLE_CLOSE_QUOTE) || (theChar == SINGLE_OPEN_QUOTE)) {
                            s = [NSMutableString stringWithFormat:@"%C", SINGLE_QUOTE];
                    } else if ((theChar == DOUBLE_CLOSE_QUOTE) || (theChar == DOUBLE_OPEN_QUOTE)) {
                            s = [NSMutableString stringWithFormat:@"%C", DOUBLE_QUOTE];
                    }
                }
                        
            }
        }
        if (s) {
                // We'll be responsible for inserting the changed text ourselves
            // ideally, this method would return the string desired, but it doesn't
            // so we'll just pop the changes in directly ourselves:
                [[textView textStorage] replaceCharactersInRange:affectedCharRange withString:s];
                return NO;               
        }
    }
    // Otherwise, let the text system insert the text as typed...
    return YES;
}

Conclusion

The Cocoa Text system is easy to use and very extensible in a straightforward manner. An improvement you might consider for this smart quoting technique is to allow for internationalization. For example, in Germany, the open quote is along the text baseline, and other languages might use ‹› or other characters for quoting. To accomplish this, you would use NSLocalizedStringFromTable() and create an entry in the .strings file for each of the quotes in the languages that you support - refer to my article on Localization in MacTech a few months back for more information.


Andrew Stone, CEO of Stone Design, www.stone.com, has been coding in Cocoa as an independent software developer for over 13 years.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Minecraft 302 - Popular sandbox building...
Minecraft allows players to build constructions out of textured cubes in a 3D procedurally generated world. Other activities in the game include exploration, gathering resources, crafting, and combat... Read more
FotoMagico 5.2b8 - Powerful slideshow cr...
FotoMagico lets you create professional slideshows from your photos and music with just a few, simple mouse clicks. It sports a very clean and intuitive yet powerful user interface. High image... Read more
TeamViewer 11.0.65452 - Establish remote...
TeamViewer gives you remote control of any computer or Mac over the Internet within seconds, or can be used for online meetings. Find out why more than 200 million users trust TeamViewer! Free for... Read more
Dropbox 9.4.49 - Cloud backup and synchr...
Dropbox is an application that creates a special Finder folder that automatically syncs online and between your computers. It allows you to both backup files and keep them up-to-date between systems... Read more
Geekbench 4.0.0 - Measure processor and...
Geekbench provides a comprehensive set of benchmarks engineered to quickly and accurately measure processor and memory performance. Designed to make benchmarks easy to run and easy to understand,... Read more
Nisus Writer Pro 2.1.5 - Multilingual wo...
Nisus Writer Pro is a powerful multilingual word processor, similar to its entry level products, but brings new features such as table of contents, indexing, bookmarks, widow and orphan control,... Read more
Default Folder X 5.0.6 - Enhances Open a...
Default Folder X attaches a toolbar to the right side of the Open and Save dialogs in any OS X-native application. The toolbar gives you fast access to various folders and commands. You just click on... Read more
Alfred 3.1 - Quick launcher for apps and...
Alfred is an award-winning productivity application for OS X. Alfred saves you time when you search for files online or on your Mac. Be more productive with hotkeys, keywords, and file actions at... Read more
MYStuff Pro 2.0.25 - Create inventories...
MYStuff Pro is the most flexible way to create detail-rich inventories for your home or small business. Add items to MYStuff by dragging and dropping existing information, uploading new images, or... Read more
OmniOutliner Pro 4.6 - Pro version of th...
OmniOutliner Pro is a flexible program for creating, collecting, and organizing information. Give your creativity a kick start by using an application that's actually designed to help you think. It's... Read more

Lifeline: Crisis Line (Games)
Lifeline: Crisis Line 1.0.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0.0 (iTunes) Description: | Read more »
BLUK (Games)
BLUK 1.1 Device: iOS Universal Category: Games Price: $1.99, Version: 1.1 (iTunes) Description: ** ‘Upcoming Game of the Year’ Finalist at NGF Awards 2015 ** ** ‘Big Indie Pitch’ Nominee at Pocket Gamer Connects 2016... | Read more »
Six! Tips, tricks, and hints for beginne...
There's nothing pretentious about Six!, the latest release from Gram Games. As puzzlers go, it's so unassuming that it took me some time to even realize why it was called what it was. Somewhere, my high school geometry teacher is now sobbing... | Read more »
Mobius Final Fantasy: Multiplayer update...
Up until now, Mobius Final Fantasy has been about as single-player an experience as an RPG can be. Not only do you play solo, but you are literally one among a seemingly unending wave of faceless warriors on the road toward the same goal. [Read... | Read more »
Find out the story behind League of Ange...
If you’re looking for a new thrilling MMORPG to play with your friends then you’ll be excited to hear that there is a sequel to one of the most well known titles in the genre – namely League of Angels 2. With a brand new 3D engine offering... | Read more »
Naruto Shippuden: Ultimate Ninja Blazing...
I'm not sure if it's possible to say you are an anime fan but also never have seen one episode of Naruto. If it is, then I resemble that remark, and if not, I offer a hearty apology. [Read more] | Read more »
5 mobile games that let you explore spac...
No Man's Sky hasn't exactly turned out to be everything it was promised. Though its core concept of exploring an unimaginably vast universe of different planets is an intriguing one, the execution has left many PS4 and PC gamers feeling like they... | Read more »
Mummy madness in new action game Tomb He...
Hot on the tail of Bump Hero, ZPlay is giving gamers another reason to get screen bashing with a brand new release. Tomb Heroes is a challenging action game in which you battle enemies in various tombs around the world. You can select from nine... | Read more »
Siralim 2 (RPG / Roguelike) (Games)
Siralim 2 (RPG / Roguelike) 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: Siralim 2 is an old-school monster catching RPG. Summon and customize hundreds of creatures to fight for you as... | Read more »
Clean Text (Productivity)
Clean Text 1.0 Device: iOS Universal Category: Productivity Price: $3.99, Version: 1.0 (iTunes) Description: | Read more »

Price Scanner via MacPrices.net

That Upgrade Itch; How Often Do You Upgrade Y...
I have a quandary to resolve as we head into what is typically a major Apple product upgrade season. My mid-2013 MacBook Air will be three years old and my iPad Air 2 will be two come late November.... Read more
Apple refurbished 12-inch iPad Pros available...
Apple has Certified Refurbished 12″ iPad Pros available for up to $160 off the cost of new iPads. An Apple one-year warranty is included with each model, and shipping is free: - 32GB 12″ iPad Pro... Read more
Tim Cook Posts Open Letter To The Apple Commu...
Apple Inc. CEO Tim Cook has posted an open letter commenting on the European Commission’s bizarre demand that Apple pay more than $14 billion in allegedly underpaid back taxes on its Irish... Read more
Streetwise Drivers Club App Now Features Open...
Streetwise Drivers Club, an app that rewards drivers with deals on everything from dining and gift cards to tires and insurance, has announced the launch of a new enhancement connecting app users... Read more
15-inch Retina MacBook Pros on sale for up to...
B&H Photo has 15″ Retina Apple MacBook Pros on sale for up to $200 off MSRP. Shipping is free, and B&H charges NY tax only: - 15″ 2.2GHz Retina MacBook Pro: $1799 $200 off MSRP - 15″ 2.5GHz... Read more
RESCUECOM 2016 Semi-Annual Computer Reliabili...
The beginning of a new school year is upon us again, in which students and parents have some very important choices to make, often including the purchase of a computer or tablet. Whether you are... Read more
VRS Design Damda Glide Series iPhone 7 and 7...
What makes the Damda Glide Series for the iPhone 7 and iPhone 7 Plus special? Case maker VRS Design says its Damda Glide Series is the first mobile case to incorporate a semi-automatic mechanism for... Read more
Apple refurbished iMacs available for up to $...
Apple has Certified Refurbished 2015 21″ & 27″ iMacs available for up to $350 off MSRP. Apple’s one-year warranty is standard, and shipping is free. The following models are available: - 21″ 3.... Read more
Clearance 2015 13-inch MacBook Airs available...
B&H Photo has clearance 2015 13″ MacBook Airs available for $350 off original MSRP. Shipping is free, and B&H charges NY sales tax only: - 13″ 1.6GHz/4GB/128GB MacBook Air (MJVE2LL/A): $829... Read more
Check Apple prices on any device with the iTr...
MacPrices is proud to offer readers a free iOS app (iPhones, iPads, & iPod touch) and Android app (Google Play and Amazon App Store) called iTracx, which allows you to glance at today’s lowest... Read more

Jobs Board

*Apple* Retail - Multiple Positions Norfolk,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
*Apple* Retail - Multiple Positions- Tampa,...
Job Description:SalesSpecialist - Retail Customer Service and SalesTransform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
SW Engineer *Apple* TV - Apple Inc. (United...
The Apple TV team is looking for excellent software engineers with experience in hardware, media management, media playback, content delivery and a passion for Read more
*Apple* Solutions Consultant - Apple (United...
Apple Solutions ConsultantJob Number: 51218534Pleasant Hill, California, United StatesPosted: Aug. 18, 2016Weekly Hours: 40.00Job SummaryAs an Apple Solutions Read more
*Apple* Solutions Consultant - Apple (United...
# Apple Solutions Consultant Job Number: 51218354 Fredericksburg, Virginia, United States Posted: Aug. 18, 2016 Weekly Hours: 40.00 **Job Summary** As an Apple Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.