MongoView/MongoView/Synax Highlighting/JavaScriptHighlighter.swift

315 lines
9.9 KiB
Swift

//
// JavaScriptHighlighter.swift
// MongoView
//
// Created by Shadowfacts on 4/1/20.
// Copyright © 2020 Shadowfacts. All rights reserved.
//
import AppKit
fileprivate let identifiers: CharacterSet = {
var set = CharacterSet.alphanumerics
set.insert(charactersIn: "$_")
return set
}()
fileprivate let identifierStarts: CharacterSet = {
var set = identifiers
set.subtract(.decimalDigits)
return set
}()
fileprivate let operators = CharacterSet(charactersIn: "+-*/<>=")
class JavaScriptHighlighter {
private let text: String
private var attributed: NSMutableAttributedString!
private var currentIndex: String.Index!
private var indent = ""
init(text: String) {
self.text = text
}
private func print(_ str: String) {
Swift.print("\(indent)\(str)")
}
private func range(from: String.Index, to: String.Index) -> NSRange {
return NSRange(from..<to, in: text)
}
private func prevCharRange() -> NSRange {
return range(from: text.index(before: currentIndex), to: currentIndex)
}
private func peek() -> Unicode.Scalar? {
guard currentIndex < text.endIndex else {
return nil
}
return text.unicodeScalars[currentIndex]
}
private func peek(length: Int) -> Substring {
let realLength = min(length, text.distance(from: currentIndex, to: text.endIndex))
return text[currentIndex..<text.index(currentIndex, offsetBy: realLength)]
}
@discardableResult
private func consume() -> Unicode.Scalar? {
let c = peek()
currentIndex = text.index(after: currentIndex)
return c
}
func highlight(mutableAttributed: NSMutableAttributedString? = nil) -> NSAttributedString {
attributed = mutableAttributed ?? NSMutableAttributedString(attributedString: NSAttributedString(string: text))
let fullRange = NSRange(location: 0, length: attributed.length)
attributed.setAttributes([
.foregroundColor: NSColor.textColor,
.font: NSFont.monospacedSystemFont(ofSize: 13, weight: .regular)
], range: fullRange)
currentIndex = text.startIndex
while currentIndex < text.endIndex {
consumeExpression()
}
return attributed
}
private func emit(token: TokenType, range: NSRange) {
let color: NSColor
switch token {
case .string:
color = .systemRed
case .number:
color = .systemBlue
case .punctuation:
color = .systemTeal
case .identifier:
return
}
attributed.addAttribute(.foregroundColor, value: color, range: range)
}
private func consumeExpression() {
consumeWhitespace()
guard let char = peek() else { return }
if identifierStarts.contains(char) {
consumeIdentifier()
} else if char == "'" || char == "\"" {
consumeString()
} else if char == "`" {
consumeTemplateString()
} else if CharacterSet.decimalDigits.contains(char) {
consumeNumber()
} else if operators.contains(char) {
consumeOperator()
} else if char == "(" {
consumeFunctionCallOrGrouping()
} else if char == "{" {
consumeObject()
} else if char == "[" {
consumeArray()
} else if char == "." {
consumeDotLookup()
} else {
consume()
}
}
private func consumeWhitespace(newlines: Bool = false) {
let charSet = newlines ? CharacterSet.whitespacesAndNewlines : .whitespaces
while let char = peek(), charSet.contains(char) {
consume()
}
}
private func consumeIdentifier() {
let identifierStart = currentIndex!
while let char = peek(), identifiers.contains(char) {
consume()
}
print("Identifier: '\(text[identifierStart..<currentIndex])'")
}
private func consumeNumber() {
let numberStart = currentIndex!
while let char = peek(), CharacterSet.decimalDigits.contains(char) {
consume()
}
if currentIndex < text.endIndex && peek() == "." {
consume()
while let char = peek(), CharacterSet.decimalDigits.contains(char) {
consume()
}
}
print("Number: \(text[numberStart..<currentIndex])")
emit(token: .number, range: range(from: numberStart, to: currentIndex))
}
private func consumeString() {
let stringStart = currentIndex!
let startChar = consume()
while currentIndex < text.endIndex && peek() != startChar && (currentIndex == text.startIndex || text[text.index(before: currentIndex)] != "\\") {
consume()
}
if currentIndex < text.endIndex {
consume() // string closing quote
}
print("String: \(text[stringStart..<currentIndex])")
emit(token: .string, range: range(from: stringStart, to: currentIndex))
}
private func consumeTemplateString() {
var stringFragmentStart: String.Index? = currentIndex
consume() // opening `
while currentIndex < text.endIndex {
if peek(length: 2) == "${" {
consume() // $
consume() // {
print("Template string fragment: '\(text[stringFragmentStart!..<currentIndex])'")
emit(token: .string, range: range(from: stringFragmentStart!, to: currentIndex))
consumeTemplateStringExpression()
stringFragmentStart = currentIndex
if currentIndex < text.endIndex && peek() == "}" {
consume()
}
} else if peek() == "`" {
stringFragmentStart = stringFragmentStart ?? currentIndex
consume() // `
print("Template string fragment: '\(text[stringFragmentStart!..<currentIndex])'")
emit(token: .string, range: range(from: stringFragmentStart!, to: currentIndex))
stringFragmentStart = nil
break
} else {
consume()
}
}
if let start = stringFragmentStart {
print("Template string fragment: '\(text[start..<currentIndex])'")
emit(token: .string, range: range(from: start, to: currentIndex))
}
}
private func consumeTemplateStringExpression() {
indent += " "
while currentIndex < text.endIndex && peek() != "}" {
consumeExpression()
}
indent = String(indent.dropLast(2))
}
private func consumeOperator() {
print("Operator: \(peek()!)")
consume()
}
private func consumeFunctionCallOrGrouping() {
consume() // (
print("Opening (")
emit(token: .punctuation, range: prevCharRange())
indent += " "
while currentIndex < text.endIndex && peek() != ")" {
consumeExpression()
}
indent = String(indent.dropLast(2))
if currentIndex < text.endIndex {
consume() // )
print("Closing )")
emit(token: .punctuation, range: prevCharRange())
}
}
private func consumeObject() {
consume() // {
print("Opening {")
emit(token: .punctuation, range: prevCharRange())
indent += " "
object:
while currentIndex < text.endIndex && peek() != "}" {
consumeObjectKey()
if peek() == ":" {
consume() // :
while currentIndex < text.endIndex && peek() != "," && peek() != "}" {
consumeExpression()
}
if currentIndex < text.endIndex {
break object
}
} else if peek() == "," {
continue
} else {
break
}
}
indent = String(indent.dropLast(2))
if currentIndex < text.endIndex {
consume() // }
print("Closing }")
emit(token: .punctuation, range: prevCharRange())
}
}
private func consumeObjectKey() {
guard let char = peek() else { return }
let keyStart = currentIndex!
if identifierStarts.contains(char) {
consumeIdentifier()
} else if char == "'" || char == "\"" {
consumeString()
}
print("Object key: '\(text[keyStart..<currentIndex])'")
}
private func consumeDotLookup() {
consume() // .
print("Dot lookup")
emit(token: .punctuation, range: prevCharRange())
}
private func consumeArray() {
consume() // [
print("Opening [")
emit(token: .punctuation, range: prevCharRange())
indent += " "
array:
while currentIndex < text.endIndex && peek() != "]" {
print("Array element")
while currentIndex < text.endIndex {
if peek() == "," {
consume() // ,
print("Array separator")
emit(token: .punctuation, range: prevCharRange())
break
} else if peek() == "]" {
break array
} else {
indent += " "
consumeExpression()
indent = String(indent.dropLast(2))
}
}
}
indent = String(indent.dropLast(2))
if currentIndex < text.endIndex {
consume() // ]
print("Closing ]")
emit(token: .punctuation, range: prevCharRange())
}
}
}
extension JavaScriptHighlighter {
enum TokenType {
case identifier
case punctuation
case number
case string
}
}