Exceeding max Text(“”) concatenation length - SwiftUI -

Question

With reference to the answer posted by Asperi (https://stackoverflow.com/users/12299030/asperi) on Question: Highlight a specific part of the text in SwiftUI

I have f

Answer 1

After much discussion in the comments, it became clear that I was hitting a maximum Text() concatenations limit, so beware, apparently there is one.

I realized however that I only needed to have a split Text("Word") when that particular word required special formatting (IE highlighting, etc), otherwise, I could concat all of the raw strings together and send that as a Text("String of words").

This approach mitigated the action of having every single word sent as a Text("Word" by itself and cut down greatly on the number of Text()'s being returned.

see code below that solved the issue:

func hilightedText(str: String) -> Text {
    let textToSearch = searched
    var result = Text(" ")
    var words: String = " "
    var foundWord = false
    for line in str.split(whereSeparator: \.isNewline) {
        for word in line.split(whereSeparator: \.isWhitespace) {
            if word.localizedStandardContains(textToSearch) {
                foundWord = true
                result += Text(words) + Text(" ") + Text(word).bold().foregroundColor(.yellow)

            } else {
                if foundWord {
                    words = ""
                }
                foundWord = false
                words += " " + word
            } 
        }
        words += "\n\n"
    }
    return result + Text(" ") + Text(words)
}

---

extension Text {
    static func += (lhs: inout Text, rhs: Text) {
        lhs = lhs + rhs
    }
}

It could use some cleanup as also discussed in the comments for splitting by whitespace, etc, but this was just to overcome the issue of crashing. Needs some additional testing before I call it good, but no more crashing..

ADDED: the suggestion to use separator by .isWhiteSpace worked, but when I put it back together, everything was a space, no more line breaks, so I added the extra split by line breaks to preserve the line breaks.

Answer 2

Hmm... unexpected limitation... anyway - learn something new.

Ok, here is improved algorithm, which should move that limitation far away.

Tested with Xcode 12 / iOS 14. (also updated code in referenced topic Highlight a specific part of the text in SwiftUI)

func hilightedText(str: String, searched: String) -> Text {
    guard !str.isEmpty && !searched.isEmpty else { return Text(str) }

    var result = Text("")

    var range = str.startIndex..<str.endIndex
    repeat {
        guard let found = str.range(of: searched, options: .caseInsensitive, range: range, locale: nil) else {
            result = result + Text(str[range])
            break
        }

        let prefix = str[range.lowerBound..<found.lowerBound]
        result = result + Text(prefix) + Text(str[found]).bold().foregroundColor(.yellow)

        range = found.upperBound..<str.endIndex
    } while (true)

    return result
}