[MTMathListBuilder] enhanced \begin{cases} environment support

No Need to use the & character at line end. The previous notation is still supported.

Sources/SwiftMath/MathRender/MTMathAtomFactory.swift

@@ -898,8 +898,8 @@ public class MTMathAtomFactory {
                 
                 return table
             } else if env == "cases" {
-                if table.numColumns != 2 {
-                    let message = "cases environment can only have 2 columns"
+                if table.numColumns != 1 && table.numColumns != 2 {
+                    let message = "cases environment can have 1 or 2 columns"
                     if error == nil {
                         error = NSError(domain: MTParseError, code: MTParseErrors.invalidNumColumns.rawValue, userInfo: [NSLocalizedDescriptionKey:message])
                     }
@@ -910,7 +910,9 @@ public class MTMathAtomFactory {
                 table.interColumnSpacing = 18
 
                 table.set(alignment: .left, forColumn: 0)
+                if table.numColumns == 2 {
                     table.set(alignment: .left, forColumn: 1)
+                }
                 
                 let style = MTMathStyle(style: .text)
                 for i in 0..<table.cells.count {

Sources/SwiftMath/MathRender/MTMathListBuilder.swift

@@ -131,6 +131,111 @@ public struct MTMathListBuilder {
         }
     }
 
+    // Analyze cases environment content to detect if & characters are present
+    mutating func analyzeCasesContent() -> Bool {
+        let savedIndex = currentCharIndex
+        var braceDepth = 0
+        var hasAmpersand = false
+
+        while currentCharIndex < string.endIndex {
+            let char = string[currentCharIndex]
+            currentCharIndex = string.index(after: currentCharIndex)
+
+            switch char {
+            case "{":
+                braceDepth += 1
+            case "}":
+                braceDepth -= 1
+                if braceDepth < 0 {
+                    // Found unmatched closing brace, likely end of environment content
+                    break
+                }
+            case "&":
+                if braceDepth == 0 {
+                    // Found & at top level (not inside nested braces)
+                    hasAmpersand = true
+                    break
+                }
+            case "\\":
+                // Skip the next character if it's a command
+                if currentCharIndex < string.endIndex {
+                    let nextChar = string[currentCharIndex]
+                    if nextChar == "e" {
+                        // Check if this might be \end{cases}
+                        let remainingChars = string[currentCharIndex...]
+                        if remainingChars.hasPrefix("end{cases}") {
+                            break
+                        }
+                    }
+                    currentCharIndex = string.index(after: currentCharIndex)
+                }
+            default:
+                break
+            }
+        }
+
+        // Restore position
+        currentCharIndex = savedIndex
+        return hasAmpersand
+    }
+
+    // Build single-column cases environment (no & separators)
+    mutating func buildSingleColumnCases(firstList: MTMathList?, isRow: Bool) -> MTMathAtom? {
+        let oldEnv = self.currentEnv
+        currentEnv = MTEnvProperties(name: "cases")
+
+        var rows = [[MTMathList]]()
+        var currentRow = 0
+
+        // Add first list if provided
+        if let first = firstList {
+            rows.append([first])
+            if isRow {
+                currentEnv!.numRows += 1
+                currentRow += 1
+                rows.append([MTMathList]())
+            }
+        } else {
+            rows.append([MTMathList]())
+        }
+
+        while !currentEnv!.ended && self.hasCharacters {
+            let list = self.buildInternal(false)
+            if list == nil {
+                return nil
+            }
+
+            if currentEnv!.numRows > currentRow {
+                // New row triggered by \\
+                currentRow = currentEnv!.numRows
+                rows.append([list!])
+            } else {
+                // Continue current row (should be single cell)
+                if rows[currentRow].isEmpty {
+                    rows[currentRow].append(list!)
+                } else {
+                    // Append to existing cell in single-column mode
+                    rows[currentRow][0].append(list!)
+                }
+            }
+        }
+
+        if !currentEnv!.ended {
+            self.setError(.missingEnd, message: "Missing \\end")
+            return nil
+        }
+
+        var error: NSError? = self.error
+        let table = MTMathAtomFactory.table(withEnvironment: "cases", rows: rows, error: &error)
+        if table == nil && self.error == nil {
+            self.error = error
+            return nil
+        }
+
+        self.currentEnv = oldEnv
+        return table
+    }
+    
     mutating func expectCharacter(_ ch: Character) -> Bool {
         MTAssertNotSpace(ch)
         self.skipSpaces()
@@ -970,6 +1075,16 @@ public struct MTMathListBuilder {
     }
     
     mutating func buildTable(env: String?, firstList: MTMathList?, isRow: Bool) -> MTMathAtom? {
+        // Special handling for cases environment - detect single vs two column structure
+        if env == "cases" {
+            let hasAmpersand = analyzeCasesContent()
+            if !hasAmpersand {
+                // Parse as single-column cases environment
+                return buildSingleColumnCases(firstList: firstList, isRow: isRow)
+            }
+            // If ampersand found, continue with standard two-column parsing
+        }
+
         // Save the current env till an new one gets built.
         let oldEnv = self.currentEnv