Merge pull request #880 from twostraws/markup-string-interpolation

MrSkwiggs · web-flow · commit 64fb3ff66a8c · 2026-05-11T13:42:53.000+02:00
Markup string interpolation
diff --git a/Sources/Ignite/Elements/Image.swift b/Sources/Ignite/Elements/Image.swift
@@ -120,7 +120,7 @@ public struct Image: InlineElement, LazyLoadable {
             return Markup("<img\(attributes) />")
         }
 
-        var output = "<picture>"
+        var output = Markup("<picture>")
 
         if let darkSourceSet = generateSourceSet(darkVariants), let value = darkSourceSet.value {
             output += "<source media=\"(prefers-color-scheme: dark)\" srcset=\"\(value)\">"
@@ -129,7 +129,7 @@ public struct Image: InlineElement, LazyLoadable {
         // Add the fallback img tag
         output += "<img\(attributes) />"
         output += "</picture>"
-        return Markup(output)
+        return output
     }
 
     /// Renders this element using publishing context passed in.
diff --git a/Sources/Ignite/Elements/Include.swift b/Sources/Ignite/Elements/Include.swift
@@ -34,7 +34,7 @@ public struct Include: HTML {
 
         do {
             let string = try String(contentsOf: fileURL)
-            return Markup(string)
+            return Markup(verbatim: string)
         } catch {
             publishingContext.addWarning("""
             Failed to find \(filename) in Includes folder; \
diff --git a/Sources/Ignite/Elements/List.swift b/Sources/Ignite/Elements/List.swift
@@ -162,7 +162,7 @@ public struct List: HTML {
     public func markup() -> Markup {
         let listAttributes = getAttributes()
 
-        var output = "<\(listElementName)\(listAttributes)>"
+        var output: Markup = "<\(listElementName)\(listAttributes)>"
 
         for originalItem in items {
             var item = originalItem
@@ -173,7 +173,7 @@ public struct List: HTML {
                 if listStyle != .automatic {
                     listableItem.attributes.append(classes: "list-group-item")
                 }
-                output += listableItem.listMarkup().string
+                output += listableItem.listMarkup()
             } else {
                 let styleClass = listStyle == .automatic ? "" : " class=\"list-group-item\""
                 item.attributes.append(classes: "m-0")
@@ -183,6 +183,6 @@ public struct List: HTML {
 
         output += "</\(listElementName)>"
 
-        return Markup(output)
+        return output
     }
 }
diff --git a/Sources/Ignite/Elements/PlainDocument.swift b/Sources/Ignite/Elements/PlainDocument.swift
@@ -42,11 +42,11 @@ public struct PlainDocument: Document, HTML {
         // Deferred head rendering to accommodate for context updates during body rendering
         let headMarkup = head.markup()
 
-        var output = "<!doctype html>"
+        var output: Markup = "<!doctype html>"
         output += "<html\(attributes)>"
-        output += headMarkup.string
-        output += bodyMarkup.string
+        output += headMarkup
+        output += bodyMarkup
         output += "</html>"
-        return Markup(output)
+        return output
     }
 }
diff --git a/Sources/Ignite/Elements/String.swift b/Sources/Ignite/Elements/String.swift
@@ -14,6 +14,6 @@ extension String: InlineElement, FormItem {
     /// Renders this element using publishing context passed in.
     /// - Returns: The HTML for this element.
     public func markup() -> Markup {
-        Markup(self)
+        Markup(verbatim: self)
     }
 }
diff --git a/Sources/Ignite/Elements/Table.swift b/Sources/Ignite/Elements/Table.swift
@@ -164,7 +164,7 @@ public struct Table: HTML {
             tableAttributes.append(classes: ["table-striped-columns"])
         }
 
-        var output = ""
+        var output = Markup()
 
         if let filterTitle {
             tableAttributes.id = "table-\(UUID().uuidString.truncatedHash)"
@@ -190,9 +190,9 @@ public struct Table: HTML {
         }
 
         output += "<tbody>"
-        output += rows.markupString()
+        output += Markup(verbatim: rows.markupString())
         output += "</tbody>"
         output += "</table>"
-        return Markup(output)
+        return output
     }
 }
diff --git a/Sources/Ignite/Elements/Text.swift b/Sources/Ignite/Elements/Text.swift
@@ -160,11 +160,7 @@ public struct Text: HTML, DropdownItem {
                 .attributes(attributes)
                 .markup()
         } else {
-            Markup(
-                "<\(font.rawValue)\(attributes)>" +
-                content.markupString() +
-                "</\(font.rawValue)>"
-            )
+            Markup("<\(font.rawValue)\(attributes)>\(content.markupString())</\(font.rawValue)>")
         }
     }
 }
diff --git a/Sources/Ignite/Elements/Video.swift b/Sources/Ignite/Elements/Video.swift
@@ -34,7 +34,7 @@ public struct Video: InlineElement, LazyLoadable {
     ///   - files: The user videos to render.
     /// - Returns: The HTML for this element.
     private func render(files: [String]) -> Markup {
-        var output = "<video controls\(attributes)>"
+        var output: Markup = "<video controls\(attributes)>"
 
         for filename in files {
             if let fileType = videoType(for: filename) {
@@ -44,7 +44,7 @@ public struct Video: InlineElement, LazyLoadable {
 
         output += "Your browser does not support the video tag."
         output += "</video>"
-        return Markup(output)
+        return output
     }
 
     /// Renders this element using publishing context passed in.
diff --git a/Sources/Ignite/Framework/Analytics/Analytics.swift b/Sources/Ignite/Framework/Analytics/Analytics.swift
@@ -27,22 +27,22 @@ public struct Analytics: HeadElement {
     public func markup() -> Markup {
         switch service {
         case .googleAnalytics(let measurementID):
-            Markup(googleAnalyticsCode(for: measurementID))
+            Markup(verbatim: googleAnalyticsCode(for: measurementID))
 
         case .plausible(let domain, let measurements):
-            Markup(plausibleCode(for: domain, using: measurements))
+            Markup(verbatim: plausibleCode(for: domain, using: measurements))
 
         case .fathom(let siteID):
-            Markup(fathomCode(for: siteID))
+            Markup(verbatim: fathomCode(for: siteID))
 
         case .clicky(let siteID):
-            Markup(clickyCode(for: siteID))
+            Markup(verbatim: clickyCode(for: siteID))
 
         case .telemetryDeck(let siteID):
-            Markup(telemetryDeckCode(for: siteID))
+            Markup(verbatim: telemetryDeckCode(for: siteID))
 
         case .custom(let code):
-            Markup(code)
+            Markup(verbatim: code)
         }
     }
 
diff --git a/Sources/Ignite/Framework/CoreAttributes.swift b/Sources/Ignite/Framework/CoreAttributes.swift
@@ -6,47 +6,10 @@
 //
 
 import Foundation
-import OrderedCollections
-
-// A typealias that allows us to use `OrderedSet` without importing OrderedCollections
-public typealias OrderedSet<Element: Hashable> = OrderedCollections.OrderedSet<Element>
-
-// A typealias that allows us to use `OrderedDictionary` without importing OrderedCollections
-public typealias OrderedDictionary<Key: Hashable, Value> = OrderedCollections.OrderedDictionary<Key, Value>
-
-// A typealias that allows us to use `UUID` without importing Foundation
-public typealias UUID = Foundation.UUID
-
-// A typealias that allows us to use `URL` without importing Foundation
-public typealias URL = Foundation.URL
-
-// A typealias that allows us to use `Data` without importing Foundation
-public typealias Data = Foundation.Data
-
-// A typealias that allows us to use `Date` without importing Foundation
-public typealias Date = Foundation.Date
-
-/// A publishing-time registration required by rendered attributes.
-enum PublishingRegistration: Hashable, Equatable, Sendable {
-    case fontFamily(Font)
-    case responsiveFont(ResponsiveValues<LengthUnit>)
-    case responsiveVisibility(ResponsiveValues<Bool>)
-
-    func apply(to context: PublishingContext) {
-        switch self {
-        case .fontFamily(let font):
-            context.cssManager.registerFontFamily(font)
-        case .responsiveFont(let values):
-            _ = context.cssManager.registerFont(values)
-        case .responsiveVisibility(let values):
-            _ = context.cssManager.registerStyles(values)
-        }
-    }
-}
 
 /// A handful of attributes that all HTML types must support, either for
 /// rendering or for publishing purposes.
-public struct CoreAttributes: Equatable, Sendable, CustomStringConvertible {
+public struct CoreAttributes: Equatable, Sendable {
     /// A unique identifier. Can be empty.
     var id = ""
 
@@ -75,10 +38,10 @@ public struct CoreAttributes: Equatable, Sendable, CustomStringConvertible {
     /// Whether this set of attributes is empty.
     var isEmpty: Bool { self == CoreAttributes() }
 
-    /// All core attributes collapsed down to a single string for easy application.
-    public var description: String {
-        registerPublishingRequirements()
-        return "\(idString)\(customAttributeString)\(classString)\(styleString)\(dataString)\(ariaString)\(eventString)"
+    /// All core attributes collapsed down to a single string for inclusion
+    /// in HTML markup output.
+    var markupAttributeString: String {
+        "\(idString)\(customAttributeString)\(classString)\(styleString)\(dataString)\(ariaString)\(eventString)"
     }
 
     /// The ID of this element, if set.
@@ -337,12 +300,11 @@ public struct CoreAttributes: Equatable, Sendable, CustomStringConvertible {
         publishingRegistrations.formUnion(other.publishingRegistrations)
     }
 
-    /// Applies publishing-time registrations when a publishing context is active.
-    private func registerPublishingRequirements() {
-        guard let context = PublishingContext.current else { return }
+}
 
-        for registration in publishingRegistrations {
-            registration.apply(to: context)
-        }
+extension String.StringInterpolation {
+    @available(*, deprecated, message: "Interpolate CoreAttributes into Markup, not String — String interpolation drops publishing-time registrations.")
+    public mutating func appendInterpolation(_ attributes: CoreAttributes) {
+        appendLiteral(attributes.markupAttributeString)
     }
 }
diff --git a/Sources/Ignite/Framework/Markup.swift b/Sources/Ignite/Framework/Markup.swift
@@ -6,7 +6,7 @@
 //
 
 /// A structure that represents HTML markup content.
-public struct Markup: Sendable {
+public struct Markup: Sendable, ExpressibleByStringLiteral, ExpressibleByStringInterpolation {
     /// The raw HTML string content.
     var string: String
 
@@ -15,10 +15,80 @@ public struct Markup: Sendable {
         return string.isEmpty
     }
 
-    /// Creates a markup instance with the given string.
-    /// - Parameter string: The string to use as HTML markup.
-    init(_ string: String = "") {
-        self.string = string
+    /// Creates an empty markup instance.
+    init() {
+        self.string = ""
+    }
+
+    /// Creates a markup instance from another markup value.
+    /// - Parameter markup: The markup value to copy.
+    init(_ markup: Markup) {
+        self = markup
+    }
+
+    /// Creates a markup instance from a raw string without interpolation handling.
+    /// - Parameter value: The string to use as HTML markup.
+    init(verbatim value: String) {
+        self.string = value
+    }
+
+    /// Creates a markup instance from a static string literal.
+    /// - Parameter value: The string literal to use as HTML markup.
+    public init(stringLiteral value: String) {
+        self.string = value
+    }
+
+    /// Creates a markup instance from an interpolated string literal.
+    /// - Parameter stringInterpolation: The accumulated interpolation state.
+    public init(stringInterpolation: StringInterpolation) {
+        if let context = PublishingContext.current {
+            for registration in stringInterpolation.pendingRegistrations {
+                registration.apply(to: context)
+            }
+        }
+        self.string = stringInterpolation.output
+    }
+
+    /// Accumulator type used by Swift's string-interpolation machinery to build a `Markup`.
+    public struct StringInterpolation: StringInterpolationProtocol {
+        /// The interpolated HTML string assembled so far.
+        var output: String = ""
+
+        /// Any pending publishing-time registrations to be applied.
+        var pendingRegistrations: [PublishingRegistration] = []
+
+        /// Creates a fresh interpolation accumulator with reserved capacity for the literal segments.
+        /// - Parameters:
+        ///   - literalCapacity: The total length of the literal segments in the string.
+        ///   - interpolationCount: The number of interpolations in the string.
+        public init(literalCapacity: Int, interpolationCount: Int) {
+            output.reserveCapacity(literalCapacity)
+        }
+
+        /// Appends a literal segment of the interpolated string.
+        /// - Parameter literal: The literal text between interpolations.
+        public mutating func appendLiteral(_ literal: String) {
+            output += literal
+        }
+
+        /// Appends a set of HTML attributes and queues their publishing-time registrations.
+        /// - Parameter attributes: The attributes to render and harvest from.
+        public mutating func appendInterpolation(_ attributes: CoreAttributes) {
+            pendingRegistrations.append(contentsOf: attributes.publishingRegistrations)
+            output += attributes.markupAttributeString
+        }
+
+        /// Appends another markup value into the interpolation.
+        /// - Parameter markup: The markup whose contents should be appended.
+        public mutating func appendInterpolation(_ markup: Markup) {
+            output += markup.string
+        }
+
+        /// Appends any other value by converting it to a string.
+        /// - Parameter value: The value to render via `String(describing:)`.
+        public mutating func appendInterpolation<T>(_ value: T) {
+            output += String(describing: value)
+        }
     }
 }
 
@@ -29,7 +99,7 @@ extension Array where Element == Markup {
     /// - Returns: A new Markup object with all strings joined
     func joined(separator: String = "") -> Markup {
         let joinedString = self.map { $0.string }.joined(separator: separator)
-        return Markup(joinedString)
+        return Markup(verbatim: joinedString)
     }
 }
 
@@ -40,7 +110,7 @@ extension Markup {
     ///   - rhs: Right-hand side Markup
     /// - Returns: A new Markup with the combined strings
     static func + (lhs: Markup, rhs: Markup) -> Markup {
-        return Markup(lhs.string + rhs.string)
+        return Markup(verbatim: lhs.string + rhs.string)
     }
 
     /// Allows for compound assignment (+=) with another Markup
diff --git a/Sources/Ignite/Framework/PublishingRegistration.swift b/Sources/Ignite/Framework/PublishingRegistration.swift
@@ -0,0 +1,26 @@
+//
+// PublishingRegistration.swift
+// Ignite
+// https://www.github.com/twostraws/Ignite
+// See LICENSE for license information.
+//
+
+import Foundation
+
+/// A publishing-time registration required by rendered attributes.
+enum PublishingRegistration: Hashable, Equatable, Sendable {
+    case fontFamily(Font)
+    case responsiveFont(ResponsiveValues<LengthUnit>)
+    case responsiveVisibility(ResponsiveValues<Bool>)
+
+    func apply(to context: PublishingContext) {
+        switch self {
+        case .fontFamily(let font):
+            context.cssManager.registerFontFamily(font)
+        case .responsiveFont(let values):
+            _ = context.cssManager.registerFont(values)
+        case .responsiveVisibility(let values):
+            _ = context.cssManager.registerStyles(values)
+        }
+    }
+}
diff --git a/Sources/Ignite/Framework/Typealiases.swift b/Sources/Ignite/Framework/Typealiases.swift
diff --git a/Tests/IgniteTesting/Framework/CoreAttributes.swift b/Tests/IgniteTesting/Framework/CoreAttributes.swift
diff --git a/Tests/IgniteTesting/Publishing/PublishingContextPreconstruction.swift b/Tests/IgniteTesting/Publishing/PublishingContextPreconstruction.swift

Original file line number	Diff line number	Diff line change
`@@ -120,7 +120,7 @@ public struct Image: InlineElement, LazyLoadable {`
`120`	`120`	`return Markup("<img\(attributes) />")`
`121`	`121`	`}`
`122`	`122`
`123`		`- var output = "<picture>"`
	`123`	`+ var output = Markup("<picture>")`
`124`	`124`
`125`	`125`	`if let darkSourceSet = generateSourceSet(darkVariants), let value = darkSourceSet.value {`
`126`	`126`	`output += "<source media=\"(prefers-color-scheme: dark)\" srcset=\"\(value)\">"`
`@@ -129,7 +129,7 @@ public struct Image: InlineElement, LazyLoadable {`
`129`	`129`	`// Add the fallback img tag`
`130`	`130`	`output += "<img\(attributes) />"`
`131`	`131`	`output += "</picture>"`
`132`		`- return Markup(output)`
	`132`	`+ return output`
`133`	`133`	`}`
`134`	`134`
`135`	`135`	`/// Renders this element using publishing context passed in.`
Original file line number	Diff line number	Diff line change
`@@ -14,6 +14,6 @@ extension String: InlineElement, FormItem {`
`14`	`14`	`/// Renders this element using publishing context passed in.`
`15`	`15`	`/// - Returns: The HTML for this element.`
`16`	`16`	`public func markup() -> Markup {`
`17`		`- Markup(self)`
	`17`	`+ Markup(verbatim: self)`
`18`	`18`	`}`
`19`	`19`	`}`
Original file line number	Diff line number	Diff line change
`@@ -164,7 +164,7 @@ public struct Table: HTML {`
`164`	`164`	`tableAttributes.append(classes: ["table-striped-columns"])`
`165`	`165`	`}`
`166`	`166`
`167`		`- var output = ""`
	`167`	`+ var output = Markup()`
`168`	`168`
`169`	`169`	`if let filterTitle {`
`170`	`170`	`tableAttributes.id = "table-\(UUID().uuidString.truncatedHash)"`
`@@ -190,9 +190,9 @@ public struct Table: HTML {`
`190`	`190`	`}`
`191`	`191`
`192`	`192`	`output += "<tbody>"`
`193`		`- output += rows.markupString()`
	`193`	`+ output += Markup(verbatim: rows.markupString())`
`194`	`194`	`output += "</tbody>"`
`195`	`195`	`output += "</table>"`
`196`		`- return Markup(output)`
	`196`	`+ return output`
`197`	`197`	`}`
`198`	`198`	`}`
Original file line number	Diff line number	Diff line change
`@@ -160,11 +160,7 @@ public struct Text: HTML, DropdownItem {`
`160`	`160`	`.attributes(attributes)`
`161`	`161`	`.markup()`
`162`	`162`	`} else {`
`163`		`- Markup(`
`164`		`- "<\(font.rawValue)\(attributes)>" +`
`165`		`- content.markupString() +`
`166`		`- "</\(font.rawValue)>"`
`167`		`- )`
	`163`	`+ Markup("<\(font.rawValue)\(attributes)>\(content.markupString())</\(font.rawValue)>")`
`168`	`164`	`}`
`169`	`165`	`}`
`170`	`166`	`}`