“One” is almost always the right answer for “however many”. You must match the number of #-signs before and after the string, from zero to however many.Let y = #"\#("Hello")"# // Interpolation with pound In Swift 5, each of the following declares "Hello", even though they use a variety of single and multiline styles: let u = "Hello" // No pounds It allows you to paste and preserve raw formatting while retaining the ability to insert escape sequences. Instead of “raw strings”, Swift has, well, let’s call them “medium rare strings”. ![]() Swift adapts each escape sequence to match the number of pound signs used at the start and end of the string. Swift adopts the extensible delimiters (skipping the ugly “r”) but retains its useful escapes, including string interpolation. You cannot incorporate interpolation or coded tabs, new lines, or returns. Rust stacks one or more pounds at each end of a string (and prefixes the letter “r”) to create what it calls “raw strings”, that is strings without further escape sequence interpretation. This system was inspired by the Rust programming language. Similarly, string interpolation becomes \#(. To insert a newline into a pound-delimited string, you type \#n and not \n. They transform escapes from simple backslashes to \#. Those extra pounds allow you to change the way Swift interprets escape sequences. Just add a pound sign ( #) to each end of your string and your backslashes are perfectly preserved without hand edits or audits: // Perfect Bill Its custom delimiters work on escape sequences the way that multiline strings work on dialog. For example, you may have escaped JSON or XML you want to paste directly into an app’s string. Each stringity escape sequence is an error waiting to happen: Įnter Swift 5. The problem becomes more pronounced when you work with pre-escaped material instead of visual art. Given that this is Bill the Cat, not much is lost aesthetically speaking, but the results are less maintainable and harder to visualize. Every escape pushes characters on that line one item to the right. You have to escape each backslash, losing the ability to evaluate your clip art source at a glance. You have inadvertent line escaping at the ends of the seventh and eighth lines as well. The others are subsumed into an unintentionally valid escape (like \'). Nearly every backslash triggers a compiler error as an invalid escape sequence. Dialog flows freely in 4.x.īut what happens when your source uses backslashes, as does this Bill the Cat clip art? // error: invalid escape sequence in literal The triple-quote string delimiter replaces the one-quote, so you don’t have to use backslash escaping. "Then you shouldn't talk," said the Hatter. With its multiple escape sequences, Swift 4.x gave us: """ Instead of: "\"I don't think.\"\n\"Then you shouldn't talk,\" said the Hatter." Let me show you an example of how this works. Multiline strings are great for preserving indentation and other formatting, plus as a bonus, you get embedded quotes for free. ![]() In Swift 4.2, you could use multiline triple-quoted strings. Let’s just start with the proposition that this was a real and meaningful challenge in your life. Maybe you were working with some kind of Unix awk client. Say, for whatever reason, you were in desperate need of Bill the Cat ASCII art in your app.
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