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Paywalls: changed variable handling to use Swift Regex #2811

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Merged
aboedo merged 6 commits into from
Jul 14, 2023
Merged

Paywalls: changed variable handling to use Swift Regex #2811

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8ac9efb
re-did regexes with swift regex
aboedo Jul 13, 2023
1a15401
fixes to regex
aboedo Jul 13, 2023
50a9665
small fixes
aboedo Jul 13, 2023
3391a92
reorganized the code
aboedo Jul 13, 2023
e0e1b2f
swiftlint
aboedo Jul 13, 2023
0b1b5ce
improvements from PR comments
aboedo Jul 14, 2023
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1 change: 1 addition & 0 deletions RevenueCatUI/Helpers/ProcessedLocalizedConfiguration.swift
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Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
import RevenueCat

/// A `PaywallData.LocalizedConfiguration` with processed variables
@available(iOS 16.0, macOS 13.0, tvOS 16.0, *)
struct ProcessedLocalizedConfiguration: PaywallLocalizedConfiguration {

var title: String
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53 changes: 31 additions & 22 deletions RevenueCatUI/Helpers/Variables.swift
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Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
import Foundation
import RegexBuilder
import RevenueCat

@available(iOS 16.0, macOS 13.0, tvOS 16.0, *)
Expand All @@ -21,44 +22,51 @@ protocol VariableDataProvider {
}

/// Processes strings, replacing `{{variable}}` with their associated content.
@available(iOS 16.0, macOS 13.0, tvOS 16.0, *)
enum VariableHandler {

static func processVariables(
in string: String,
with provider: VariableDataProvider
) -> String {
let matches = Self.extractVariables(from: string)
var replacedString = string
let range = NSRange(string.startIndex..., in: string)
let matches = Self.regex.matches(in: string, options: [], range: range)

for match in matches.reversed() {
let variableNameRange = match.range(at: 1)
if let variableNameRange = Range(variableNameRange, in: string) {
let variableName = String(string[variableNameRange])
let replacementValue = provider.value(for: variableName)

let adjustedRange = NSRange(
location: variableNameRange.lowerBound.utf16Offset(in: string) - Self.pattern.count / 2,
length: string.distance(from: variableNameRange.lowerBound,
to: variableNameRange.upperBound) + Self.pattern.count
)
let replacementRange = Range(adjustedRange, in: replacedString)!

replacedString = replacedString.replacingCharacters(in: replacementRange, with: replacementValue)
}
for variableMatch in matches.reversed() {
let replacementValue = provider.value(for: variableMatch.variable)
replacedString = replacedString.replacingCharacters(in: variableMatch.range, with: replacementValue)

@aboedo aboedo Jul 13, 2023

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the range comes in for free

Comment on lines 36 to 37

@NachoSoto NachoSoto Jul 13, 2023

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So. Much. Simpler.

}

return replacedString
}

private static let pattern = "{{ }}"
// Fix-me: this can be implemented using the new Regex from Swift.
// This regex is known at compile time and tested:
// swiftlint:disable:next force_try
private static let regex = try! NSRegularExpression(pattern: "\\{\\{ (\\w+) \\}\\}", options: [])
private static func extractVariables(from expression: String) -> [VariableMatch] {
let variablePattern = Regex {
OneOrMore {
"{{ "
Capture {
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OneOrMore(.word)
}
" }}"
}
Comment on lines 45 to 51

@NachoSoto NachoSoto Jul 13, 2023

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So nice

}

return expression.matches(of: variablePattern).map { match in
let (_, variable) = match.output
return VariableMatch(variable: String(variable), range: match.range)
Comment on lines 54 to 56

@aboedo aboedo Jul 13, 2023

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the neat thing here is that the range is for the full expression, the variable is the content of the Capture.

}
}

private struct VariableMatch {

let variable: String
let range: Range<String.Index>

}

}

@available(iOS 16.0, macOS 13.0, tvOS 16.0, *)
extension String {

func processed(with provider: VariableDataProvider) -> Self {
Expand All @@ -67,6 +75,7 @@ extension String {

}

@available(iOS 16.0, macOS 13.0, tvOS 16.0, *)
private extension VariableDataProvider {

func value(for variableName: String) -> String {
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