A quoted mapping key followed by a space and then ':' ('"key" : value')
failed to parse: the scanner synthesizes the implicit mapping-key token by
checking the character immediately after the key, but a quoted scalar
stops at its closing quote, leaving the separating space, whereas a plain
scalar consumes that space into itself and ends at the colon. The quoted
path now looks past spaces for the colon, which the spec allows between an
implicit key and its value indicator.
Quoted keys with no space, quoted values, and plain keys (which already
worked with a space) are unaffected. Measured against the official YAML
test-suite, parse-level conformance rises from 238/333 (71.5%) to
240/333 (72.1%), with no regression.
401 lines
14 KiB
Swift
401 lines
14 KiB
Swift
extension PureYAML.Parsing {
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struct Scanner {
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init() {}
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func scan(_ yaml: String) throws -> [Token] {
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var state = State(reader: Reader(yaml))
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state.append(.streamStart)
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while !state.reader.isAtEnd {
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if isLineBreak(state.reader.peek()) {
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state.reader.advance()
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captureBlockScalarBlankLine(&state)
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state.isAtLineStart = true
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continue
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}
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if state.isAtLineStart {
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try scanIndentation(&state)
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if state.reader.isAtEnd {
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break
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}
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if isLineBreak(state.reader.peek()) {
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continue
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}
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if try scanDirectiveOrDocumentMarker(&state) {
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continue
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}
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state.isAtLineStart = false
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}
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try scanToken(&state)
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}
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closeIndentation(&state)
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state.append(.streamEnd)
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return state.tokens
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}
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}
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}
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extension PureYAML.Parsing.Scanner {
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struct State {
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var reader: PureYAML.Parsing.Reader
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var tokens: [PureYAML.Parsing.Token] = []
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var indentation: [Int] = [0]
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var isAtLineStart = true
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var hasDocumentContent = false
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var hasDocumentStartMarker = false
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var isDocumentClosed = false
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var flowDepth = 0
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var flowContexts: [PureYAML.Parsing.ScannerFlowContext] = []
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var validImplicitIndentation: Set<Int> = []
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var pendingBlockScalarIndentation = false
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var pendingBlockScalarIndentationIndicator: Int?
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var pendingBlockScalarLeadingBlankLines = 0
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var blockScalarIndentation: Int?
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var blockScalarContentPrefix = ""
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var tagHandles = [
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"!": "!",
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"!!": "tag:yaml.org,2002:",
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]
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mutating func append(_ kind: PureYAML.Parsing.TokenKind) {
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let mark = reader.mark
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tokens.append(PureYAML.Parsing.Token(kind: kind, mark: mark, endMark: mark))
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markDocumentContentIfNeeded(kind)
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}
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mutating func append(
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_ kind: PureYAML.Parsing.TokenKind,
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mark: PureYAML.Parsing.Mark,
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endMark: PureYAML.Parsing.Mark,
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) {
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tokens.append(PureYAML.Parsing.Token(kind: kind, mark: mark, endMark: endMark))
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markDocumentContentIfNeeded(kind)
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}
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mutating func markDocumentContentIfNeeded(_ kind: PureYAML.Parsing.TokenKind) {
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switch kind {
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case .comment, .dedent, .documentEnd, .documentStart, .indent, .streamEnd, .streamStart:
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return
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default:
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hasDocumentContent = true
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}
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}
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var isExpectingFlowMappingKey: Bool {
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flowContexts.last?.kind == .mapping
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&& flowContexts.last?.isExpectingKey == true
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}
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}
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}
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extension PureYAML.Parsing.Scanner {
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func scanToken(_ state: inout State) throws {
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skipSeparation(&state)
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guard let character = state.reader.peek(), !isLineBreak(character) else {
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return
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}
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if state.blockScalarIndentation != nil {
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scanBlockScalarContent(&state)
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return
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}
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if try scanLineIndicatorToken(character, state: &state) {
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return
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}
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if scanFlowToken(character, state: &state) {
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return
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}
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if try scanQuotedOrBlockScalarToken(character, state: &state) {
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return
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}
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if try scanNodePropertyToken(character, state: &state) {
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return
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}
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scanPlainScalar(&state)
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}
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func scanLineIndicatorToken(
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_ character: Character,
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state: inout State,
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) throws -> Bool {
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switch character {
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case "#":
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scanComment(&state)
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return true
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case "-" where isBlockEntry(state.reader):
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scanFixedToken(.blockEntry, state: &state)
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return true
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case "?" where isIndicatorBoundary(state.reader.peek(offset: 1)):
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scanFixedToken(.mappingKey, state: &state)
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return true
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case ":" where isAtMappingValueIndicator(state: state):
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scanFixedToken(.mappingValue, state: &state)
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return true
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default:
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return false
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}
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}
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func scanFlowToken(
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_ character: Character,
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state: inout State,
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) -> Bool {
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switch character {
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case "[":
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state.flowDepth += 1
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state.flowContexts.append(.init(kind: .sequence, isExpectingKey: false))
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scanFixedToken(.flowSequenceStart, state: &state)
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return true
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case "]":
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state.flowDepth = max(0, state.flowDepth - 1)
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scanFixedToken(.flowSequenceEnd, state: &state)
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_ = state.flowContexts.popLast()
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return true
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case "{":
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state.flowDepth += 1
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state.flowContexts.append(.init(kind: .mapping, isExpectingKey: true))
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scanFixedToken(.flowMappingStart, state: &state)
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return true
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case "}":
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state.flowDepth = max(0, state.flowDepth - 1)
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scanFixedToken(.flowMappingEnd, state: &state)
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_ = state.flowContexts.popLast()
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return true
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case ",":
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scanFixedToken(.flowEntry, state: &state)
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if state.flowContexts.last?.kind == .mapping {
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state.flowContexts[state.flowContexts.count - 1].isExpectingKey = true
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}
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return true
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default:
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return false
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}
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}
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func scanNodePropertyToken(
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_ character: Character,
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state: inout State,
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) throws -> Bool {
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switch character {
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case "&":
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try scanNamedToken(
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kind: PureYAML.Parsing.TokenKind.anchor,
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missingNameError: PureYAML.Parsing.ParseError.expectedAnchorName,
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state: &state,
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)
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return true
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case "*":
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try scanNamedToken(
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kind: PureYAML.Parsing.TokenKind.alias,
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missingNameError: PureYAML.Parsing.ParseError.expectedAliasName,
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state: &state,
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)
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return true
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case "!":
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try scanTag(&state)
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return true
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default:
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return false
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}
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}
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func scanQuotedOrBlockScalarToken(
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_ character: Character,
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state: inout State,
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) throws -> Bool {
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switch character {
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case "\"":
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try scanQuotedScalar(.doubleQuoted, state: &state)
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return true
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case "'":
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try scanQuotedScalar(.singleQuoted, state: &state)
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return true
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case "|":
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scanBlockScalarHeader(.literal, state: &state)
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return true
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case ">":
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scanBlockScalarHeader(.folded, state: &state)
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return true
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default:
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return false
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}
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}
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func skipSeparation(_ state: inout State) {
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while state.reader.peek() == " " {
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state.reader.advance()
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}
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}
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func scanFixedToken(
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_ kind: PureYAML.Parsing.TokenKind,
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state: inout State,
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) {
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let start = state.reader.mark
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state.reader.advance()
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state.append(kind, mark: start, endMark: state.reader.mark)
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if case .blockEntry = kind, hasNodeOnSameLine(afterCurrentPositionIn: state.reader) {
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state.validImplicitIndentation.insert(start.column + 1)
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}
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if case .mappingValue = kind, state.flowContexts.last?.kind == .mapping {
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state.flowContexts[state.flowContexts.count - 1].isExpectingKey = false
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}
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}
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func scanComment(_ state: inout State) {
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let start = state.reader.mark
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state.reader.advance()
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if state.reader.peek() == " " {
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state.reader.advance()
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}
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let value = state.reader.consume { character in
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!isLineBreak(character)
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}
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state.append(.comment(value), mark: start, endMark: state.reader.mark)
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}
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func scanQuotedScalar(
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_ style: PureYAML.Parsing.ScalarStyle,
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state: inout State,
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) throws {
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let start = state.reader.mark
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let quote: Character = style == .doubleQuoted ? "\"" : "'"
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state.reader.advance()
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var value = ""
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var previousWasEscape = false
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while let character = state.reader.peek() {
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if style == .singleQuoted, character == quote, state.reader.peek(offset: 1) == quote {
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value.append(character)
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state.reader.advance()
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value.append(character)
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state.reader.advance()
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continue
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}
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if character == quote, !previousWasEscape {
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break
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}
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value.append(character)
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previousWasEscape = character == "\\" && style == .doubleQuoted && !previousWasEscape
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state.reader.advance()
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if character != "\\" {
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previousWasEscape = false
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}
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}
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guard state.reader.peek() == quote else {
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throw PureYAML.Parsing.ParseError.unterminatedQuotedString(line: start.line)
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}
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state.reader.advance()
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// Unlike a plain scalar (which consumes the space before a `:` into itself), a quoted scalar
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// stops at its closing quote, so the reader sits at any spaces before a `:`. A space between
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// an implicit key and its mapping-value indicator is allowed, so look past them.
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if isAtMappingValueIndicatorAfterSpaces(state: state) {
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state.append(.mappingKey, mark: start, endMark: start)
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}
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state.append(.scalar(value: value, style: style), mark: start, endMark: state.reader.mark)
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}
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func scanBlockScalarHeader(
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_ style: PureYAML.Parsing.BlockScalarStyle,
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state: inout State,
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) {
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let start = state.reader.mark
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var chomping = PureYAML.Parsing.BlockScalarChomping.clip
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var indentationIndicator: Int?
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state.reader.advance()
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while let character = state.reader.peek(), isBlockScalarHeaderCharacter(character) {
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if character == "-" {
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chomping = .strip
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} else if character == "+" {
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chomping = .keep
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} else if character.isNumber {
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indentationIndicator = Int(String(character))
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}
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state.reader.advance()
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}
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state.append(
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.blockScalarHeader(style: style, chomping: chomping),
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mark: start,
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endMark: state.reader.mark,
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)
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state.pendingBlockScalarIndentation = true
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state.pendingBlockScalarIndentationIndicator = indentationIndicator
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}
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func scanBlockScalarContent(_ state: inout State) {
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let start = state.reader.mark
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let value = state.blockScalarContentPrefix + state.reader.consume { character in
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!isLineBreak(character)
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}
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state.blockScalarContentPrefix = ""
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state.append(.scalar(value: value, style: .plain), mark: start, endMark: state.reader.mark)
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}
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func scanNamedToken(
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kind: (String) -> PureYAML.Parsing.TokenKind,
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missingNameError: (Int) -> PureYAML.Parsing.ParseError,
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state: inout State,
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) throws {
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let start = state.reader.mark
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state.reader.advance()
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let name = state.reader.consume { character in
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!isTokenTerminator(character)
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}
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guard !name.isEmpty else {
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throw missingNameError(start.line)
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}
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state.append(kind(name), mark: start, endMark: state.reader.mark)
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}
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func scanTag(_ state: inout State) throws {
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let start = state.reader.mark
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state.reader.advance()
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var value = "!"
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if state.reader.peek() == "<" {
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value.append(state.reader.advance() ?? "<")
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var didClose = false
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while let character = state.reader.peek() {
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value.append(character)
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state.reader.advance()
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if character == ">" {
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didClose = true
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break
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}
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}
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guard didClose else {
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throw PureYAML.Parsing.ParseError.unterminatedTag(line: start.line)
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}
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} else {
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value += state.reader.consume { character in
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!isTokenTerminator(character)
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}
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value = expandTag(value, state: state)
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}
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state.append(.tag(value), mark: start, endMark: state.reader.mark)
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}
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func scanPlainScalar(_ state: inout State) {
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let start = state.reader.mark
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var value = ""
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while let character = state.reader.peek() {
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if shouldEndPlainScalar(character, state: state, accumulated: value) {
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break
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}
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value.append(character)
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state.reader.advance()
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}
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var trimmed = trimTrailingSpaces(value)
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let isMappingKey = appendMappingKeyIfNeeded(start: start, state: &state)
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if !isMappingKey {
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trimmed = scanPlainScalarContinuations(
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after: trimmed,
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firstLineIndent: start.column - 1,
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state: &state,
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)
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}
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state.append(.scalar(value: trimmed, style: .plain), mark: start, endMark: state.reader.mark)
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}
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}
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