import Foundation
let pattern = #"([+\-*\/]{2,}\d+)|(\([+\*\/])|((?<![\d\)])[+\*\/]\()|(\)[+\-\*\/](?![\d\()]))|((?<![\d\)])(?=[+\*\/]\d+))|(\(\))|(\d+[+\-\*\/](?![\d(]))|((?<![\d\+\-\*\/])\([+\-\*\/])|((?<![\d])[+\-\*\/]\))"#
let regex = try! NSRegularExpression(pattern: pattern, options: .anchorsMatchLines)
let testString = #"""
-(1+2)*10
2+3*(5-6/4)/3+26-122*3/29
(?>![\\d)])[+\-\*\/]\(
([+\-*\/]{2,}\d+)|(\([+\*\/])|((?>![\\d)])[+\-\*\/]\()|([^\d\)][+\-\*\/]\()|((?<=[+\-\*\/])(0\d+))|(\)[+\-\*\/][^\d\)])|((?<![\d\)])(?=[+\*\/]\d+))|(\(\))
(0*1-0-3)-5/0-4-(3*(-2
010 + 1
4-1-
(1-2)*(3-4)
空字符串 🆗
错误的运算符 🆗
错误的运算数 🆗
括号不匹配 ？
空括号 🆗
连续的运算符，例如--5
运算符为正数时，其符号+必须省略，例如+2+4定义为非法，而负数时为合法，例如-2+4 前面补零
程序要能处理表达式中间出现的空格（输入表达式中存在空格为合法情况）
(后面是运算符 + / * 没数字！
)前面是运算符 + - * / 没数字！
-)
(1 -6)-(-1+2)
010 0 开头的数字
4-
-(9-1) 允许
(9-1)- 不允许
+9+1 不允许
-9+1 允许
其他不符合表达式书写规则的情况
(2*2)*2)
-100*100-(13*4)
"""#
let stringRange = NSRange(location: 0, length: testString.utf16.count)
let matches = regex.matches(in: testString, range: stringRange)
var result: [[String]] = []
for match in matches {
var groups: [String] = []
for rangeIndex in 1 ..< match.numberOfRanges {
let nsRange = match.range(at: rangeIndex)
guard !NSEqualRanges(nsRange, NSMakeRange(NSNotFound, 0)) else { continue }
let string = (testString as NSString).substring(with: nsRange)
groups.append(string)
}
if !groups.isEmpty {
result.append(groups)
}
}
print(result)
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Swift 5.2, please visit: https://developer.apple.com/documentation/foundation/nsregularexpression