import Foundation
let pattern = #"(^<\d{4}> )|(\\(\w+)?\{.*?\})"#
let regex = try! NSRegularExpression(pattern: pattern, options: .anchorsMatchLines)
let testString = ##"""
// Resources for SEEN0001.TXT
#character '美佐枝'
#character '春原'
#character 'ボタン'
<0000> \{美佐枝}You little goblin...
<0001> Unable to contain her fury, Misae grabs both of Sunohara's legs...
<0002> \{春原}Heh?
<0003> ...and proceeds to use her killing move, The Giant Swing.
<0004> \{美佐枝}Uryaaaaaaaaaaaaaaaaaaa!
<0005> \{春原}Uwaaaaaaaaaaaaaah!
<0006> \{ボタン}Puhiiii.
<0007> \{春原}Uwaaaaaaaaaaah!
<0008> \{春原}Uwaaaaaaaaaaah!
<0009> \{春原}Uwaaaaaaaaaaah!
<0010> \{春原}Geeh!
<0171> \size{intA[1001]}*BOOM*\size{}\shake{4}
<0145> \size{intA[1001]}Dammit! Stupid rugby players!!\size{}
"""##
let stringRange = NSRange(location: 0, length: testString.utf16.count)
let substitutionString = #""#
let result = regex.stringByReplacingMatches(in: testString, range: stringRange, withTemplate: substitutionString)
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