spb/metrika Public

1//2//  ParseError.swift3//  Metrika4//5//  Author:  Simon-Pierre Boucher6//  Contact: contact@spboucher.ai7//  Copyright © 2026 Simon-Pierre Boucher. All rights reserved.8//910/// Parse failure with the 1-based source column and, where possible, a11/// suggested fix (CLAUDE.md §4: errors must cite column position and12/// suggest fixes via Levenshtein distance on known verbs).13public struct ZQParseError: Error, Equatable, Sendable, CustomStringConvertible {14    public var message: String15    public var column: Int16    public var suggestion: String?1718    public init(message: String, column: Int, suggestion: String? = nil) {19        self.message = message20        self.column = column21        self.suggestion = suggestion22    }2324    public var description: String {25        var text = "parse error at column \(column): \(message)"26        if let suggestion {27            text += "\n  did you mean '\(suggestion)'?"28        }29        return text30    }31}3233/// Levenshtein edit distance, used to suggest the closest known verb for34/// an unrecognized command.35public func levenshteinDistance(_ a: String, _ b: String) -> Int {36    let a = Array(a), b = Array(b)37    if a.isEmpty { return b.count }38    if b.isEmpty { return a.count }3940    var previous = Array(0...b.count)41    var current = [Int](repeating: 0, count: b.count + 1)4243    for i in 1...a.count {44        current[0] = i45        for j in 1...b.count {46            let substitution = previous[j - 1] + (a[i - 1] == b[j - 1] ? 0 : 1)47            current[j] = min(previous[j] + 1, current[j - 1] + 1, substitution)48        }49        swap(&previous, &current)50    }51    return previous[b.count]52}53