[MTMathListBuilder][MTTypesetter] add \cfrac support

Sources/SwiftMath/MathRender/MTMathList.swift

@@ -328,6 +328,10 @@ public class MTFraction: MTMathAtom {
     public var rightDelimiter = ""
     public var numerator: MTMathList?
     public var denominator: MTMathList?
+
+    // Continued fraction properties
+    public var isContinuedFraction: Bool = false
+    public var alignment: String = "c"  // "l", "r", "c" for left, right, center
     
     init(_ frac: MTFraction?) {
         super.init(frac)
@@ -338,6 +342,8 @@ public class MTFraction: MTMathAtom {
             self.hasRule = frac.hasRule
             self.leftDelimiter = frac.leftDelimiter
             self.rightDelimiter = frac.rightDelimiter
+            self.isContinuedFraction = frac.isContinuedFraction
+            self.alignment = frac.alignment
         }
     }
     

Sources/SwiftMath/MathRender/MTMathListBuilder.swift

@@ -508,7 +508,14 @@ public struct MTMathListBuilder {
                 }
                 if atom.type == .fraction {
                     if let frac = atom as? MTFraction {
-                        if frac.hasRule {
+                        if frac.isContinuedFraction {
+                            // Generate \cfrac with optional alignment
+                            if frac.alignment != "c" {
+                                str += "\\cfrac[\(frac.alignment)]{\(mathListToString(frac.numerator!))}{\(mathListToString(frac.denominator!))}"
+                            } else {
+                                str += "\\cfrac{\(mathListToString(frac.numerator!))}{\(mathListToString(frac.denominator!))}"
+                            }
+                        } else if frac.hasRule {
                             str += "\\frac{\(mathListToString(frac.numerator!))}{\(mathListToString(frac.denominator!))}"
                         } else {
                             let command: String
@@ -685,6 +692,28 @@ public struct MTMathListBuilder {
         } else if command == "frac" {
             // A fraction command has 2 arguments
             let frac = MTFraction()
+            frac.numerator = self.buildInternal(true)
+            frac.denominator = self.buildInternal(true)
+            return frac;
+        } else if command == "cfrac" {
+            // A continued fraction command with optional alignment and 2 arguments
+            let frac = MTFraction()
+            frac.isContinuedFraction = true
+
+            // Parse optional alignment parameter [l], [r], [c]
+            skipSpaces()
+            if hasCharacters && string[currentCharIndex] == "[" {
+                _ = getNextCharacter() // consume '['
+                let alignmentChar = getNextCharacter()
+                if alignmentChar == "l" || alignmentChar == "r" || alignmentChar == "c" {
+                    frac.alignment = String(alignmentChar)
+                }
+                // Consume closing ']'
+                if hasCharacters && string[currentCharIndex] == "]" {
+                    _ = getNextCharacter()
+                }
+            }
+
             frac.numerator = self.buildInternal(true)
             frac.denominator = self.buildInternal(true)
             return frac;
@@ -981,6 +1010,27 @@ public struct MTMathListBuilder {
             return accent
         } else if command == "frac" {
             let frac = MTFraction()
+            frac.numerator = self.buildInternal(true)
+            frac.denominator = self.buildInternal(true)
+            return frac
+        } else if command == "cfrac" {
+            let frac = MTFraction()
+            frac.isContinuedFraction = true
+
+            // Parse optional alignment parameter [l], [r], [c]
+            skipSpaces()
+            if hasCharacters && string[currentCharIndex] == "[" {
+                _ = getNextCharacter() // consume '['
+                let alignmentChar = getNextCharacter()
+                if alignmentChar == "l" || alignmentChar == "r" || alignmentChar == "c" {
+                    frac.alignment = String(alignmentChar)
+                }
+                // Consume closing ']'
+                if hasCharacters && string[currentCharIndex] == "]" {
+                    _ = getNextCharacter()
+                }
+            }
+
             frac.numerator = self.buildInternal(true)
             frac.denominator = self.buildInternal(true)
             return frac

Sources/SwiftMath/MathRender/MTTypesetter.swift

@@ -990,9 +990,22 @@ class MTTypesetter {
     
     func makeFraction(_ frac:MTFraction?) -> MTDisplay? {
         // lay out the parts of the fraction
-        let fractionStyle = self.fractionStyle;
-        let numeratorDisplay = MTTypesetter.createLineForMathList(frac!.numerator, font:font, style:fractionStyle(), cramped:false)
-        let denominatorDisplay = MTTypesetter.createLineForMathList(frac!.denominator, font:font, style:fractionStyle(), cramped:true)
+        let numeratorStyle: MTLineStyle
+        let denominatorStyle: MTLineStyle
+
+        if frac!.isContinuedFraction {
+            // Continued fractions always use display style
+            numeratorStyle = .display
+            denominatorStyle = .display
+        } else {
+            // Regular fractions use adaptive style
+            let fractionStyle = self.fractionStyle;
+            numeratorStyle = fractionStyle()
+            denominatorStyle = fractionStyle()
+        }
+
+        let numeratorDisplay = MTTypesetter.createLineForMathList(frac!.numerator, font:font, style:numeratorStyle, cramped:false)
+        let denominatorDisplay = MTTypesetter.createLineForMathList(frac!.denominator, font:font, style:denominatorStyle, cramped:true)
         
         // determine the location of the numerator
         var numeratorShiftUp = self.numeratorShiftUp(frac!.hasRule)