58b9c3b00c
* Implement Recursive Transforms * Correct test names * apply suggestions * format * add comments * move the parse function * refine `parseTransforms()` function * refinements * format * Swift Format again --------- Co-authored-by: Adam Fowler <adamfowler71@gmail.com>
427 lines
18 KiB
Swift
427 lines
18 KiB
Swift
//===----------------------------------------------------------------------===//
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//
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// This source file is part of the Hummingbird server framework project
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//
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// Copyright (c) 2021-2021 the Hummingbird authors
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// Licensed under Apache License v2.0
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//
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// See LICENSE.txt for license information
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// See hummingbird/CONTRIBUTORS.txt for the list of Hummingbird authors
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//
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// SPDX-License-Identifier: Apache-2.0
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//
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//===----------------------------------------------------------------------===//
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extension MustacheTemplate {
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/// Error return by `MustacheTemplate.parse`. Includes information about where error occurred
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public struct ParserError: Swift.Error {
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public let context: MustacheParserContext
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public let error: Swift.Error
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}
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/// Error generated by `MustacheTemplate.parse`
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public enum Error: Swift.Error {
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/// the end section does not match the name of the start section
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case sectionCloseNameIncorrect
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/// tag was badly formatted
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case unfinishedName
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/// was expecting a section end
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case expectedSectionEnd
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/// set delimiter tag badly formatted
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case invalidSetDelimiter
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/// cannot apply transform to inherited section
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case transformAppliedToInheritanceSection
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/// illegal token inside inherit section of partial
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case illegalTokenInsideInheritSection
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/// text found inside inherit section of partial
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case textInsideInheritSection
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/// config variable syntax is wrong
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case invalidConfigVariableSyntax
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/// unrecognised config variable
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case unrecognisedConfigVariable
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}
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struct ParserState {
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var sectionName: String?
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var sectionTransforms: [String] = []
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var newLine: Bool
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var startDelimiter: String
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var endDelimiter: String
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init() {
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self.sectionName = nil
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self.newLine = true
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self.startDelimiter = "{{"
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self.endDelimiter = "}}"
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}
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func withSectionName(_ name: String, transforms: [String] = []) -> ParserState {
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var newValue = self
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newValue.sectionName = name
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newValue.sectionTransforms = transforms
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return newValue
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}
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func withDelimiters(start: String, end: String) -> ParserState {
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var newValue = self
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newValue.startDelimiter = start
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newValue.endDelimiter = end
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return newValue
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}
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}
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/// parse mustache text to generate a list of tokens
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static func parse(_ string: String) throws -> [Token] {
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var parser = Parser(string)
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do {
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return try self.parse(&parser, state: .init())
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} catch {
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throw ParserError(context: parser.getContext(), error: error)
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}
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}
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/// parse section in mustache text
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static func parse(_ parser: inout Parser, state: ParserState) throws -> [Token] {
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var tokens: [Token] = []
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var state = state
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var whiteSpaceBefore: Substring = ""
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while !parser.reachedEnd() {
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// if new line read whitespace
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if state.newLine {
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whiteSpaceBefore = parser.read(while: Set(" \t"))
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}
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let text = try readUntilDelimiterOrNewline(&parser, state: state)
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// if we hit a newline add text
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if parser.current().isNewline {
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tokens.append(.text(whiteSpaceBefore + text + String(parser.current())))
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state.newLine = true
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parser.unsafeAdvance()
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continue
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}
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// we have found a tag
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// whatever text we found before the tag should be added as a token
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if text.count > 0 {
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tokens.append(.text(whiteSpaceBefore + text))
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whiteSpaceBefore = ""
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state.newLine = false
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}
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// have we reached the end of the text
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if parser.reachedEnd() {
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break
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}
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var setNewLine = false
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switch parser.current() {
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case "#":
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// section
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parser.unsafeAdvance()
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let (name, transforms) = try parseName(&parser, state: state)
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if self.isStandalone(&parser, state: state) {
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setNewLine = true
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} else if whiteSpaceBefore.count > 0 {
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tokens.append(.text(String(whiteSpaceBefore)))
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whiteSpaceBefore = ""
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}
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let sectionTokens = try parse(&parser, state: state.withSectionName(name, transforms: transforms))
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tokens.append(.section(name: name, transforms: transforms, template: MustacheTemplate(sectionTokens)))
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case "^":
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// inverted section
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parser.unsafeAdvance()
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let (name, transforms) = try parseName(&parser, state: state)
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if self.isStandalone(&parser, state: state) {
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setNewLine = true
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} else if whiteSpaceBefore.count > 0 {
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tokens.append(.text(String(whiteSpaceBefore)))
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whiteSpaceBefore = ""
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}
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let sectionTokens = try parse(&parser, state: state.withSectionName(name, transforms: transforms))
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tokens.append(.invertedSection(name: name, transforms: transforms, template: MustacheTemplate(sectionTokens)))
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case "$":
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// inherited section
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parser.unsafeAdvance()
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let (name, transforms) = try parseName(&parser, state: state)
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// ERROR: can't have transform applied to inherited sections
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guard transforms.isEmpty else { throw Error.transformAppliedToInheritanceSection }
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if self.isStandalone(&parser, state: state) {
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setNewLine = true
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} else if whiteSpaceBefore.count > 0 {
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tokens.append(.text(String(whiteSpaceBefore)))
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whiteSpaceBefore = ""
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}
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let sectionTokens = try parse(&parser, state: state.withSectionName(name, transforms: transforms))
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tokens.append(.inheritedSection(name: name, template: MustacheTemplate(sectionTokens)))
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case "/":
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// end of section
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parser.unsafeAdvance()
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let position = parser.position
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let (name, transforms) = try parseName(&parser, state: state)
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guard name == state.sectionName, transforms == state.sectionTransforms else {
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parser.unsafeSetPosition(position)
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throw Error.sectionCloseNameIncorrect
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}
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if self.isStandalone(&parser, state: state) {
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setNewLine = true
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} else if whiteSpaceBefore.count > 0 {
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tokens.append(.text(String(whiteSpaceBefore)))
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whiteSpaceBefore = ""
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}
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return tokens
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case "!":
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// comment
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parser.unsafeAdvance()
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_ = try self.parseComment(&parser, state: state)
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setNewLine = self.isStandalone(&parser, state: state)
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case "{":
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// unescaped variable
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if whiteSpaceBefore.count > 0 {
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tokens.append(.text(String(whiteSpaceBefore)))
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whiteSpaceBefore = ""
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}
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parser.unsafeAdvance()
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let (name, transforms) = try parseName(&parser, state: state)
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guard try parser.read("}") else { throw Error.unfinishedName }
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tokens.append(.unescapedVariable(name: name, transforms: transforms))
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case "&":
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// unescaped variable
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if whiteSpaceBefore.count > 0 {
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tokens.append(.text(String(whiteSpaceBefore)))
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whiteSpaceBefore = ""
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}
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parser.unsafeAdvance()
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let (name, transforms) = try parseName(&parser, state: state)
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tokens.append(.unescapedVariable(name: name, transforms: transforms))
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case ">":
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// partial
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parser.unsafeAdvance()
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let name = try parsePartialName(&parser, state: state)
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if whiteSpaceBefore.count > 0 {
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tokens.append(.text(String(whiteSpaceBefore)))
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}
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if self.isStandalone(&parser, state: state) {
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setNewLine = true
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tokens.append(.partial(name, indentation: String(whiteSpaceBefore), inherits: nil))
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} else {
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tokens.append(.partial(name, indentation: nil, inherits: nil))
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}
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whiteSpaceBefore = ""
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case "<":
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// partial with inheritance
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parser.unsafeAdvance()
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let name = try parsePartialName(&parser, state: state)
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var indent: String?
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if self.isStandalone(&parser, state: state) {
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setNewLine = true
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} else if whiteSpaceBefore.count > 0 {
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indent = String(whiteSpaceBefore)
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tokens.append(.text(indent!))
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whiteSpaceBefore = ""
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}
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let sectionTokens = try parse(&parser, state: state.withSectionName(name))
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var inherit: [String: MustacheTemplate] = [:]
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// parse tokens in section to extract inherited sections
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for token in sectionTokens {
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switch token {
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case .inheritedSection(let name, let template):
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inherit[name] = template
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case .text:
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break
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default:
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throw Error.illegalTokenInsideInheritSection
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}
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}
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tokens.append(.partial(name, indentation: indent, inherits: inherit))
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case "=":
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// set delimiter
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parser.unsafeAdvance()
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state = try self.parserSetDelimiter(&parser, state: state)
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setNewLine = self.isStandalone(&parser, state: state)
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case "%":
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// read config variable
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parser.unsafeAdvance()
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if let token = try self.readConfigVariable(&parser, state: state) {
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tokens.append(token)
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}
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setNewLine = self.isStandalone(&parser, state: state)
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default:
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// variable
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if whiteSpaceBefore.count > 0 {
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tokens.append(.text(String(whiteSpaceBefore)))
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whiteSpaceBefore = ""
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}
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let (name, transforms) = try parseName(&parser, state: state)
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tokens.append(.variable(name: name, transforms: transforms))
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}
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state.newLine = setNewLine
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}
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// should never get here if reading section
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guard state.sectionName == nil else {
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throw Error.expectedSectionEnd
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}
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return tokens
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}
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/// read until we hit either the start delimiter of a tag or a newline
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static func readUntilDelimiterOrNewline(_ parser: inout Parser, state: ParserState) throws -> String {
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var untilSet: Set<Character> = ["\n", "\r\n"]
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guard let delimiterFirstChar = state.startDelimiter.first else { return "" }
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var totalText = ""
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untilSet.insert(delimiterFirstChar)
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while !parser.reachedEnd() {
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// read until we hit either a newline or "{"
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let text = try parser.read(until: untilSet, throwOnOverflow: false)
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totalText += text
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// if new line append all text read plus newline
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if parser.current().isNewline {
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break
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} else if parser.current() == delimiterFirstChar {
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if try parser.read(string: state.startDelimiter) {
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break
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}
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totalText += String(delimiterFirstChar)
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parser.unsafeAdvance()
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}
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}
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return totalText
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}
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/// parse variable name
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static func parseName(_ parser: inout Parser, state: ParserState) throws -> (String, [String]) {
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parser.read(while: \.isWhitespace)
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let text = String(parser.read(while: self.sectionNameChars))
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parser.read(while: \.isWhitespace)
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guard try parser.read(string: state.endDelimiter) else { throw Error.unfinishedName }
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// does the name include brackets. If so this is a transform call
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var nameParser = Parser(String(text))
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let string = nameParser.read(while: self.sectionNameCharsWithoutBrackets)
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if nameParser.reachedEnd() {
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return (text, [])
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} else {
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// parse function parameter, as we have just parsed a function name
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guard nameParser.current() == "(" else { throw Error.unfinishedName }
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nameParser.unsafeAdvance()
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func parseTransforms(existing: [Substring]) throws -> (Substring, [Substring]) {
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let name = nameParser.read(while: self.sectionNameCharsWithoutBrackets)
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switch nameParser.current() {
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case ")":
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// Transforms are ending
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nameParser.unsafeAdvance()
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// We need to have a `)` for each transform that we've parsed
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guard nameParser.read(while: ")") + 1 == existing.count,
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nameParser.reachedEnd()
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else {
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throw Error.unfinishedName
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}
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return (name, existing)
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case "(":
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// Parse the next transform
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nameParser.unsafeAdvance()
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var transforms = existing
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transforms.append(name)
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return try parseTransforms(existing: transforms)
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default:
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throw Error.unfinishedName
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}
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}
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let (parameterName, transforms) = try parseTransforms(existing: [string])
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return (String(parameterName), transforms.map(String.init))
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}
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}
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/// parse partial name
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static func parsePartialName(_ parser: inout Parser, state: ParserState) throws -> String {
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parser.read(while: \.isWhitespace)
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let text = String(parser.read(while: self.sectionNameChars))
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parser.read(while: \.isWhitespace)
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guard try parser.read(string: state.endDelimiter) else { throw Error.unfinishedName }
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return text
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}
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static func parseComment(_ parser: inout Parser, state: ParserState) throws -> String {
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let text = try parser.read(untilString: state.endDelimiter, throwOnOverflow: true, skipToEnd: true)
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return String(text)
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}
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static func parserSetDelimiter(_ parser: inout Parser, state: ParserState) throws -> ParserState {
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let startDelimiter: Substring
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let endDelimiter: Substring
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do {
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parser.read(while: \.isWhitespace)
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startDelimiter = try parser.read(until: \.isWhitespace)
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parser.read(while: \.isWhitespace)
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endDelimiter = try parser.read(until: { $0 == "=" || $0.isWhitespace })
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parser.read(while: \.isWhitespace)
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} catch {
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throw Error.invalidSetDelimiter
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}
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guard try parser.read("=") else { throw Error.invalidSetDelimiter }
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guard try parser.read(string: state.endDelimiter) else { throw Error.invalidSetDelimiter }
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guard startDelimiter.count > 0, endDelimiter.count > 0 else { throw Error.invalidSetDelimiter }
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return state.withDelimiters(start: String(startDelimiter), end: String(endDelimiter))
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}
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static func readConfigVariable(_ parser: inout Parser, state: ParserState) throws -> Token? {
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let variable: Substring
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let value: Substring
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do {
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parser.read(while: \.isWhitespace)
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variable = parser.read(while: self.sectionNameCharsWithoutBrackets)
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parser.read(while: \.isWhitespace)
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guard try parser.read(":") else { throw Error.invalidConfigVariableSyntax }
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parser.read(while: \.isWhitespace)
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value = parser.read(while: self.sectionNameCharsWithoutBrackets)
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parser.read(while: \.isWhitespace)
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guard try parser.read(string: state.endDelimiter) else { throw Error.invalidConfigVariableSyntax }
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} catch {
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throw Error.invalidConfigVariableSyntax
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}
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// do both variable and value have content
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guard variable.count > 0, value.count > 0 else { throw Error.invalidConfigVariableSyntax }
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switch variable {
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case "CONTENT_TYPE":
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guard let contentType = MustacheContentTypes.get(String(value)) else { throw Error.unrecognisedConfigVariable }
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return .contentType(contentType)
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default:
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throw Error.unrecognisedConfigVariable
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}
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}
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static func hasLineFinished(_ parser: inout Parser) -> Bool {
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var parser2 = parser
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if parser.reachedEnd() { return true }
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parser2.read(while: Set(" \t"))
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if parser2.current().isNewline {
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parser2.unsafeAdvance()
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try! parser.setPosition(parser2.position)
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return true
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}
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return false
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}
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static func isStandalone(_ parser: inout Parser, state: ParserState) -> Bool {
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return state.newLine && self.hasLineFinished(&parser)
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}
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private static let sectionNameCharsWithoutBrackets = Set<Character>("0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ.-_?")
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private static let sectionNameChars = Set<Character>("0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ.-_?()")
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private static let partialNameChars = Set<Character>("0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ.-_()")
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}
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