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Unified Diff: yaml/lib/src/parser.dart

Issue 1400473008: Roll Observatory packages and add a roll script (Closed) Base URL: git@github.com:dart-lang/observatory_pub_packages.git@master
Patch Set: Created 5 years, 2 months ago
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Index: yaml/lib/src/parser.dart
diff --git a/yaml/lib/src/parser.dart b/yaml/lib/src/parser.dart
deleted file mode 100644
index 8bb131f8346bb1e6d2df1d498c537131b5bc9f36..0000000000000000000000000000000000000000
--- a/yaml/lib/src/parser.dart
+++ /dev/null
@@ -1,816 +0,0 @@
-// Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-library yaml.parser;
-
-import 'package:source_span/source_span.dart';
-import 'package:string_scanner/string_scanner.dart';
-
-import 'event.dart';
-import 'scanner.dart';
-import 'style.dart';
-import 'token.dart';
-import 'utils.dart';
-import 'yaml_document.dart';
-import 'yaml_exception.dart';
-
-/// A parser that reads [Token]s emitted by a [Scanner] and emits [Event]s.
-///
-/// This is based on the libyaml parser, available at
-/// https://github.com/yaml/libyaml/blob/master/src/parser.c. The license for
-/// that is available in ../../libyaml-license.txt.
-class Parser {
- /// The underlying [Scanner] that generates [Token]s.
- final Scanner _scanner;
-
- /// The stack of parse states for nested contexts.
- final _states = new List<_State>();
-
- /// The current parse state.
- var _state = _State.STREAM_START;
-
- /// The custom tag directives, by tag handle.
- final _tagDirectives = new Map<String, TagDirective>();
-
- /// Whether the parser has finished parsing.
- bool get isDone => _state == _State.END;
-
- /// Creates a parser that parses [source].
- ///
- /// [sourceUrl] can be a String or a [Uri].
- Parser(String source, {sourceUrl})
- : _scanner = new Scanner(source, sourceUrl: sourceUrl);
-
- /// Consumes and returns the next event.
- Event parse() {
- try {
- if (isDone) throw new StateError("No more events.");
- var event = _stateMachine();
- return event;
- } on StringScannerException catch (error) {
- throw new YamlException(error.message, error.span);
- }
- }
-
- /// Dispatches parsing based on the current state.
- Event _stateMachine() {
- switch (_state) {
- case _State.STREAM_START:
- return _parseStreamStart();
- case _State.DOCUMENT_START:
- return _parseDocumentStart();
- case _State.DOCUMENT_CONTENT:
- return _parseDocumentContent();
- case _State.DOCUMENT_END:
- return _parseDocumentEnd();
- case _State.BLOCK_NODE:
- return _parseNode(block: true);
- case _State.BLOCK_NODE_OR_INDENTLESS_SEQUENCE:
- return _parseNode(block: true, indentlessSequence: true);
- case _State.FLOW_NODE:
- return _parseNode();
- case _State.BLOCK_SEQUENCE_FIRST_ENTRY:
- // Scan past the `BLOCK-SEQUENCE-FIRST-ENTRY` token to the
- // `BLOCK-SEQUENCE-ENTRY` token.
- _scanner.scan();
- return _parseBlockSequenceEntry();
- case _State.BLOCK_SEQUENCE_ENTRY:
- return _parseBlockSequenceEntry();
- case _State.INDENTLESS_SEQUENCE_ENTRY:
- return _parseIndentlessSequenceEntry();
- case _State.BLOCK_MAPPING_FIRST_KEY:
- // Scan past the `BLOCK-MAPPING-FIRST-KEY` token to the
- // `BLOCK-MAPPING-KEY` token.
- _scanner.scan();
- return _parseBlockMappingKey();
- case _State.BLOCK_MAPPING_KEY:
- return _parseBlockMappingKey();
- case _State.BLOCK_MAPPING_VALUE:
- return _parseBlockMappingValue();
- case _State.FLOW_SEQUENCE_FIRST_ENTRY:
- return _parseFlowSequenceEntry(first: true);
- case _State.FLOW_SEQUENCE_ENTRY:
- return _parseFlowSequenceEntry();
- case _State.FLOW_SEQUENCE_ENTRY_MAPPING_KEY:
- return _parseFlowSequenceEntryMappingKey();
- case _State.FLOW_SEQUENCE_ENTRY_MAPPING_VALUE:
- return _parseFlowSequenceEntryMappingValue();
- case _State.FLOW_SEQUENCE_ENTRY_MAPPING_END:
- return _parseFlowSequenceEntryMappingEnd();
- case _State.FLOW_MAPPING_FIRST_KEY:
- return _parseFlowMappingKey(first: true);
- case _State.FLOW_MAPPING_KEY:
- return _parseFlowMappingKey();
- case _State.FLOW_MAPPING_VALUE:
- return _parseFlowMappingValue();
- case _State.FLOW_MAPPING_EMPTY_VALUE:
- return _parseFlowMappingValue(empty: true);
- default:
- throw "Unreachable";
- }
- }
-
- /// Parses the production:
- ///
- /// stream ::=
- /// STREAM-START implicit_document? explicit_document* STREAM-END
- /// ************
- Event _parseStreamStart() {
- var token = _scanner.scan();
- assert(token.type == TokenType.STREAM_START);
-
- _state = _State.DOCUMENT_START;
- return new Event(EventType.STREAM_START, token.span);
- }
-
- /// Parses the productions:
- ///
- /// implicit_document ::= block_node DOCUMENT-END*
- /// *
- /// explicit_document ::=
- /// DIRECTIVE* DOCUMENT-START block_node? DOCUMENT-END*
- /// *************************
- Event _parseDocumentStart() {
- var token = _scanner.peek();
-
- // libyaml requires any document beyond the first in the stream to have an
- // explicit document start indicator, but the spec allows it to be omitted
- // as long as there was an end indicator.
-
- // Parse extra document end indicators.
- while (token.type == TokenType.DOCUMENT_END) {
- token = _scanner.advance();
- }
-
- if (token.type != TokenType.VERSION_DIRECTIVE &&
- token.type != TokenType.TAG_DIRECTIVE &&
- token.type != TokenType.DOCUMENT_START &&
- token.type != TokenType.STREAM_END) {
- // Parse an implicit document.
- _processDirectives();
- _states.add(_State.DOCUMENT_END);
- _state = _State.BLOCK_NODE;
- return new DocumentStartEvent(token.span.start.pointSpan());
- }
-
- if (token.type == TokenType.STREAM_END) {
- _state = _State.END;
- _scanner.scan();
- return new Event(EventType.STREAM_END, token.span);
- }
-
- // Parse an explicit document.
- var start = token.span;
- var pair = _processDirectives();
- var versionDirective = pair.first;
- var tagDirectives = pair.last;
- token = _scanner.peek();
- if (token.type != TokenType.DOCUMENT_START) {
- throw new YamlException("Expected document start.", token.span);
- }
-
- _states.add(_State.DOCUMENT_END);
- _state = _State.DOCUMENT_CONTENT;
- _scanner.scan();
- return new DocumentStartEvent(start.expand(token.span),
- versionDirective: versionDirective,
- tagDirectives: tagDirectives,
- isImplicit: false);
- }
-
- /// Parses the productions:
- ///
- /// explicit_document ::=
- /// DIRECTIVE* DOCUMENT-START block_node? DOCUMENT-END*
- /// ***********
- Event _parseDocumentContent() {
- var token = _scanner.peek();
-
- switch (token.type) {
- case TokenType.VERSION_DIRECTIVE:
- case TokenType.TAG_DIRECTIVE:
- case TokenType.DOCUMENT_START:
- case TokenType.DOCUMENT_END:
- case TokenType.STREAM_END:
- _state = _states.removeLast();
- return _processEmptyScalar(token.span.start);
- default:
- return _parseNode(block: true);
- }
- }
-
- /// Parses the productions:
- ///
- /// implicit_document ::= block_node DOCUMENT-END*
- /// *************
- /// explicit_document ::=
- /// DIRECTIVE* DOCUMENT-START block_node? DOCUMENT-END*
- /// *************
- Event _parseDocumentEnd() {
- _tagDirectives.clear();
- _state = _State.DOCUMENT_START;
-
- var token = _scanner.peek();
- if (token.type == TokenType.DOCUMENT_END) {
- _scanner.scan();
- return new DocumentEndEvent(token.span, isImplicit: false);
- } else {
- return new DocumentEndEvent(
- token.span.start.pointSpan(), isImplicit: true);
- }
- }
-
- /// Parses the productions:
- ///
- /// block_node_or_indentless_sequence ::=
- /// ALIAS
- /// *****
- /// | properties (block_content | indentless_block_sequence)?
- /// ********** *
- /// | block_content | indentless_block_sequence
- /// *
- /// block_node ::= ALIAS
- /// *****
- /// | properties block_content?
- /// ********** *
- /// | block_content
- /// *
- /// flow_node ::= ALIAS
- /// *****
- /// | properties flow_content?
- /// ********** *
- /// | flow_content
- /// *
- /// properties ::= TAG ANCHOR? | ANCHOR TAG?
- /// *************************
- /// block_content ::= block_collection | flow_collection | SCALAR
- /// ******
- /// flow_content ::= flow_collection | SCALAR
- /// ******
- Event _parseNode({bool block: false, bool indentlessSequence: false}) {
- var token = _scanner.peek();
-
- if (token is AliasToken) {
- _scanner.scan();
- _state = _states.removeLast();
- return new AliasEvent(token.span, token.name);
- }
-
- var anchor;
- var tagToken;
- var span = token.span.start.pointSpan();
- parseAnchor() {
- anchor = token.name;
- span = span.expand(token.span);
- token = _scanner.advance();
- }
-
- parseTag() {
- tagToken = token;
- span = span.expand(token.span);
- token = _scanner.advance();
- }
-
- if (token is AnchorToken) {
- parseAnchor();
- if (token is TagToken) parseTag();
- } else if (token is TagToken) {
- parseTag();
- if (token is AnchorToken) parseAnchor();
- }
-
- var tag;
- if (tagToken != null) {
- if (tagToken.handle == null) {
- tag = tagToken.suffix;
- } else {
- var tagDirective = _tagDirectives[tagToken.handle];
- if (tagDirective == null) {
- throw new YamlException("Undefined tag handle.", tagToken.span);
- }
-
- tag = tagDirective.prefix + tagToken.suffix;
- }
- }
-
- if (indentlessSequence && token.type == TokenType.BLOCK_ENTRY) {
- _state = _State.INDENTLESS_SEQUENCE_ENTRY;
- return new SequenceStartEvent(
- span.expand(token.span), CollectionStyle.BLOCK,
- anchor: anchor, tag: tag);
- }
-
- if (token is ScalarToken) {
- // All non-plain scalars have the "!" tag by default.
- if (tag == null && token.style != ScalarStyle.PLAIN) tag = "!";
-
- _state = _states.removeLast();
- _scanner.scan();
- return new ScalarEvent(
- span.expand(token.span), token.value, token.style,
- anchor: anchor, tag: tag);
- }
-
- if (token.type == TokenType.FLOW_SEQUENCE_START) {
- _state = _State.FLOW_SEQUENCE_FIRST_ENTRY;
- return new SequenceStartEvent(
- span.expand(token.span), CollectionStyle.FLOW,
- anchor: anchor, tag: tag);
- }
-
- if (token.type == TokenType.FLOW_MAPPING_START) {
- _state = _State.FLOW_MAPPING_FIRST_KEY;
- return new MappingStartEvent(
- span.expand(token.span), CollectionStyle.FLOW,
- anchor: anchor, tag: tag);
- }
-
- if (block && token.type == TokenType.BLOCK_SEQUENCE_START) {
- _state = _State.BLOCK_SEQUENCE_FIRST_ENTRY;
- return new SequenceStartEvent(
- span.expand(token.span), CollectionStyle.BLOCK,
- anchor: anchor, tag: tag);
- }
-
-
- if (block && token.type == TokenType.BLOCK_MAPPING_START) {
- _state = _State.BLOCK_MAPPING_FIRST_KEY;
- return new MappingStartEvent(
- span.expand(token.span), CollectionStyle.BLOCK,
- anchor: anchor, tag: tag);
- }
-
- if (anchor != null || tag != null) {
- _state = _states.removeLast();
- return new ScalarEvent(
- span, '', ScalarStyle.PLAIN,
- anchor: anchor, tag: tag);
- }
-
- throw new YamlException("Expected node content.", span);
- }
-
- /// Parses the productions:
- ///
- /// block_sequence ::=
- /// BLOCK-SEQUENCE-START (BLOCK-ENTRY block_node?)* BLOCK-END
- /// ******************** *********** * *********
- Event _parseBlockSequenceEntry() {
- var token = _scanner.peek();
-
- if (token.type == TokenType.BLOCK_ENTRY) {
- token = _scanner.advance();
-
- if (token.type == TokenType.BLOCK_ENTRY ||
- token.type == TokenType.BLOCK_END) {
- _state = _State.BLOCK_SEQUENCE_ENTRY;
- return _processEmptyScalar(token.span.end);
- } else {
- _states.add(_State.BLOCK_SEQUENCE_ENTRY);
- return _parseNode(block: true);
- }
- }
-
- if (token.type == TokenType.BLOCK_END) {
- _scanner.scan();
- _state = _states.removeLast();
- return new Event(EventType.SEQUENCE_END, token.span);
- }
-
- throw new YamlException("While parsing a block collection, expected '-'.",
- token.span.start.pointSpan());
- }
-
- /// Parses the productions:
- ///
- /// indentless_sequence ::= (BLOCK-ENTRY block_node?)+
- /// *********** *
- Event _parseIndentlessSequenceEntry() {
- var token = _scanner.peek();
-
- if (token.type != TokenType.BLOCK_ENTRY) {
- _state = _states.removeLast();
- return new Event(EventType.SEQUENCE_END, token.span.start.pointSpan());
- }
-
- var start = token.span.start;
- token = _scanner.advance();
-
- if (token.type == TokenType.BLOCK_ENTRY ||
- token.type == TokenType.KEY ||
- token.type == TokenType.VALUE ||
- token.type == TokenType.BLOCK_END) {
- _state = _State.INDENTLESS_SEQUENCE_ENTRY;
- return _processEmptyScalar(start);
- } else {
- _states.add(_State.INDENTLESS_SEQUENCE_ENTRY);
- return _parseNode(block: true);
- }
- }
-
- /// Parses the productions:
- ///
- /// block_mapping ::= BLOCK-MAPPING_START
- /// *******************
- /// ((KEY block_node_or_indentless_sequence?)?
- /// *** *
- /// (VALUE block_node_or_indentless_sequence?)?)*
- ///
- /// BLOCK-END
- /// *********
- Event _parseBlockMappingKey() {
- var token = _scanner.peek();
- if (token.type == TokenType.KEY) {
- var start = token.span.start;
- token = _scanner.advance();
-
- if (token.type == TokenType.KEY ||
- token.type == TokenType.VALUE ||
- token.type == TokenType.BLOCK_END) {
- _state = _State.BLOCK_MAPPING_VALUE;
- return _processEmptyScalar(start);
- } else {
- _states.add(_State.BLOCK_MAPPING_VALUE);
- return _parseNode(block: true, indentlessSequence: true);
- }
- }
-
- // libyaml doesn't allow empty keys without an explicit key indicator, but
- // the spec does. See example 8.18:
- // http://yaml.org/spec/1.2/spec.html#id2798896.
- if (token.type == TokenType.VALUE) {
- _state = _State.BLOCK_MAPPING_VALUE;
- return _processEmptyScalar(token.span.start);
- }
-
- if (token.type == TokenType.BLOCK_END) {
- _scanner.scan();
- _state = _states.removeLast();
- return new Event(EventType.MAPPING_END, token.span);
- }
-
- throw new YamlException("Expected a key while parsing a block mapping.",
- token.span.start.pointSpan());
- }
-
- /// Parses the productions:
- ///
- /// block_mapping ::= BLOCK-MAPPING_START
- ///
- /// ((KEY block_node_or_indentless_sequence?)?
- ///
- /// (VALUE block_node_or_indentless_sequence?)?)*
- /// ***** *
- /// BLOCK-END
- ///
- Event _parseBlockMappingValue() {
- var token = _scanner.peek();
-
- if (token.type != TokenType.VALUE) {
- _state = _State.BLOCK_MAPPING_KEY;
- return _processEmptyScalar(token.span.start);
- }
-
- var start = token.span.start;
- token = _scanner.advance();
- if (token.type == TokenType.KEY ||
- token.type == TokenType.VALUE ||
- token.type == TokenType.BLOCK_END) {
- _state = _State.BLOCK_MAPPING_KEY;
- return _processEmptyScalar(start);
- } else {
- _states.add(_State.BLOCK_MAPPING_KEY);
- return _parseNode(block: true, indentlessSequence: true);
- }
- }
-
- /// Parses the productions:
- ///
- /// flow_sequence ::= FLOW-SEQUENCE-START
- /// *******************
- /// (flow_sequence_entry FLOW-ENTRY)*
- /// * **********
- /// flow_sequence_entry?
- /// *
- /// FLOW-SEQUENCE-END
- /// *****************
- /// flow_sequence_entry ::=
- /// flow_node | KEY flow_node? (VALUE flow_node?)?
- /// *
- Event _parseFlowSequenceEntry({bool first: false}) {
- if (first) _scanner.scan();
- var token = _scanner.peek();
-
- if (token.type != TokenType.FLOW_SEQUENCE_END) {
- if (!first) {
- if (token.type != TokenType.FLOW_ENTRY) {
- throw new YamlException(
- "While parsing a flow sequence, expected ',' or ']'.",
- token.span.start.pointSpan());
- }
-
- token = _scanner.advance();
- }
-
- if (token.type == TokenType.KEY) {
- _state = _State.FLOW_SEQUENCE_ENTRY_MAPPING_KEY;
- _scanner.scan();
- return new MappingStartEvent(
- token.span, CollectionStyle.FLOW);
- } else if (token.type != TokenType.FLOW_SEQUENCE_END) {
- _states.add(_State.FLOW_SEQUENCE_ENTRY);
- return _parseNode();
- }
- }
-
- _scanner.scan();
- _state = _states.removeLast();
- return new Event(EventType.SEQUENCE_END, token.span);
- }
-
- /// Parses the productions:
- ///
- /// flow_sequence_entry ::=
- /// flow_node | KEY flow_node? (VALUE flow_node?)?
- /// *** *
- Event _parseFlowSequenceEntryMappingKey() {
- var token = _scanner.peek();
-
- if (token.type == TokenType.VALUE ||
- token.type == TokenType.FLOW_ENTRY ||
- token.type == TokenType.FLOW_SEQUENCE_END) {
- // libyaml consumes the token here, but that seems like a bug, since it
- // always causes [_parseFlowSequenceEntryMappingValue] to emit an empty
- // scalar.
-
- var start = token.span.start;
- _state = _State.FLOW_SEQUENCE_ENTRY_MAPPING_VALUE;
- return _processEmptyScalar(start);
- } else {
- _states.add(_State.FLOW_SEQUENCE_ENTRY_MAPPING_VALUE);
- return _parseNode();
- }
- }
-
- /// Parses the productions:
- ///
- /// flow_sequence_entry ::=
- /// flow_node | KEY flow_node? (VALUE flow_node?)?
- /// ***** *
- Event _parseFlowSequenceEntryMappingValue() {
- var token = _scanner.peek();
-
- if (token.type == TokenType.VALUE) {
- token = _scanner.advance();
- if (token.type != TokenType.FLOW_ENTRY &&
- token.type != TokenType.FLOW_SEQUENCE_END) {
- _states.add(_State.FLOW_SEQUENCE_ENTRY_MAPPING_END);
- return _parseNode();
- }
- }
-
- _state = _State.FLOW_SEQUENCE_ENTRY_MAPPING_END;
- return _processEmptyScalar(token.span.start);
- }
-
- /// Parses the productions:
- ///
- /// flow_sequence_entry ::=
- /// flow_node | KEY flow_node? (VALUE flow_node?)?
- /// *
- Event _parseFlowSequenceEntryMappingEnd() {
- _state = _State.FLOW_SEQUENCE_ENTRY;
- return new Event(EventType.MAPPING_END,
- _scanner.peek().span.start.pointSpan());
- }
-
- /// Parses the productions:
- ///
- /// flow_mapping ::= FLOW-MAPPING-START
- /// ******************
- /// (flow_mapping_entry FLOW-ENTRY)*
- /// * **********
- /// flow_mapping_entry?
- /// ******************
- /// FLOW-MAPPING-END
- /// ****************
- /// flow_mapping_entry ::=
- /// flow_node | KEY flow_node? (VALUE flow_node?)?
- /// * *** *
- Event _parseFlowMappingKey({bool first: false}) {
- if (first) _scanner.scan();
- var token = _scanner.peek();
-
- if (token.type != TokenType.FLOW_MAPPING_END) {
- if (!first) {
- if (token.type != TokenType.FLOW_ENTRY) {
- throw new YamlException(
- "While parsing a flow mapping, expected ',' or '}'.",
- token.span.start.pointSpan());
- }
-
- token = _scanner.advance();
- }
-
- if (token.type == TokenType.KEY) {
- token = _scanner.advance();
- if (token.type != TokenType.VALUE &&
- token.type != TokenType.FLOW_ENTRY &&
- token.type != TokenType.FLOW_MAPPING_END) {
- _states.add(_State.FLOW_MAPPING_VALUE);
- return _parseNode();
- } else {
- _state = _State.FLOW_MAPPING_VALUE;
- return _processEmptyScalar(token.span.start);
- }
- } else if (token.type != TokenType.FLOW_MAPPING_END) {
- _states.add(_State.FLOW_MAPPING_EMPTY_VALUE);
- return _parseNode();
- }
- }
-
- _scanner.scan();
- _state = _states.removeLast();
- return new Event(EventType.MAPPING_END, token.span);
- }
-
- /// Parses the productions:
- ///
- /// flow_mapping_entry ::=
- /// flow_node | KEY flow_node? (VALUE flow_node?)?
- /// * ***** *
- Event _parseFlowMappingValue({bool empty: false}) {
- var token = _scanner.peek();
-
- if (empty) {
- _state = _State.FLOW_MAPPING_KEY;
- return _processEmptyScalar(token.span.start);
- }
-
- if (token.type == TokenType.VALUE) {
- token = _scanner.advance();
- if (token.type != TokenType.FLOW_ENTRY &&
- token.type != TokenType.FLOW_MAPPING_END) {
- _states.add(_State.FLOW_MAPPING_KEY);
- return _parseNode();
- }
- }
-
- _state = _State.FLOW_MAPPING_KEY;
- return _processEmptyScalar(token.span.start);
- }
-
- /// Generate an empty scalar event.
- Event _processEmptyScalar(SourceLocation location) =>
- new ScalarEvent(location.pointSpan(), '', ScalarStyle.PLAIN);
-
- /// Parses directives.
- Pair<VersionDirective, List<TagDirective>> _processDirectives() {
- var token = _scanner.peek();
-
- var versionDirective;
- var tagDirectives = [];
- while (token.type == TokenType.VERSION_DIRECTIVE ||
- token.type == TokenType.TAG_DIRECTIVE) {
- if (token is VersionDirectiveToken) {
- if (versionDirective != null) {
- throw new YamlException("Duplicate %YAML directive.", token.span);
- }
-
- if (token.major != 1 || token.minor == 0) {
- throw new YamlException(
- "Incompatible YAML document. This parser only supports YAML 1.1 "
- "and 1.2.",
- token.span);
- } else if (token.minor > 2) {
- // TODO(nweiz): Print to stderr when issue 6943 is fixed and dart:io
- // is available.
- warn("Warning: this parser only supports YAML 1.1 and 1.2.",
- token.span);
- }
-
- versionDirective = new VersionDirective(token.major, token.minor);
- } else if (token is TagDirectiveToken) {
- var tagDirective = new TagDirective(token.handle, token.prefix);
- _appendTagDirective(tagDirective, token.span);
- tagDirectives.add(tagDirective);
- }
-
- token = _scanner.advance();
- }
-
- _appendTagDirective(
- new TagDirective("!", "!"),
- token.span.start.pointSpan(),
- allowDuplicates: true);
- _appendTagDirective(
- new TagDirective("!!", "tag:yaml.org,2002:"),
- token.span.start.pointSpan(),
- allowDuplicates: true);
-
- return new Pair(versionDirective, tagDirectives);
- }
-
- /// Adds a tag directive to the directives stack.
- void _appendTagDirective(TagDirective newDirective, FileSpan span,
- {bool allowDuplicates: false}) {
- if (_tagDirectives.containsKey(newDirective.handle)) {
- if (allowDuplicates) return;
- throw new YamlException("Duplicate %TAG directive.", span);
- }
-
- _tagDirectives[newDirective.handle] = newDirective;
- }
-}
-
-/// The possible states for the parser.
-class _State {
- /// Expect [TokenType.STREAM_START].
- static const STREAM_START = const _State("STREAM_START");
-
- /// Expect the beginning of an implicit document.
- static const IMPLICIT_DOCUMENT_START =
- const _State("IMPLICIT_DOCUMENT_START");
-
- /// Expect [TokenType.DOCUMENT_START].
- static const DOCUMENT_START = const _State("DOCUMENT_START");
-
- /// Expect the content of a document.
- static const DOCUMENT_CONTENT = const _State("DOCUMENT_CONTENT");
-
- /// Expect [TokenType.DOCUMENT_END].
- static const DOCUMENT_END = const _State("DOCUMENT_END");
-
- /// Expect a block node.
- static const BLOCK_NODE = const _State("BLOCK_NODE");
-
- /// Expect a block node or indentless sequence.
- static const BLOCK_NODE_OR_INDENTLESS_SEQUENCE =
- const _State("BLOCK_NODE_OR_INDENTLESS_SEQUENCE");
-
- /// Expect a flow node.
- static const FLOW_NODE = const _State("FLOW_NODE");
-
- /// Expect the first entry of a block sequence.
- static const BLOCK_SEQUENCE_FIRST_ENTRY =
- const _State("BLOCK_SEQUENCE_FIRST_ENTRY");
-
- /// Expect an entry of a block sequence.
- static const BLOCK_SEQUENCE_ENTRY = const _State("BLOCK_SEQUENCE_ENTRY");
-
- /// Expect an entry of an indentless sequence.
- static const INDENTLESS_SEQUENCE_ENTRY =
- const _State("INDENTLESS_SEQUENCE_ENTRY");
-
- /// Expect the first key of a block mapping.
- static const BLOCK_MAPPING_FIRST_KEY =
- const _State("BLOCK_MAPPING_FIRST_KEY");
-
- /// Expect a block mapping key.
- static const BLOCK_MAPPING_KEY = const _State("BLOCK_MAPPING_KEY");
-
- /// Expect a block mapping value.
- static const BLOCK_MAPPING_VALUE = const _State("BLOCK_MAPPING_VALUE");
-
- /// Expect the first entry of a flow sequence.
- static const FLOW_SEQUENCE_FIRST_ENTRY =
- const _State("FLOW_SEQUENCE_FIRST_ENTRY");
-
- /// Expect an entry of a flow sequence.
- static const FLOW_SEQUENCE_ENTRY = const _State("FLOW_SEQUENCE_ENTRY");
-
- /// Expect a key of an ordered mapping.
- static const FLOW_SEQUENCE_ENTRY_MAPPING_KEY =
- const _State("FLOW_SEQUENCE_ENTRY_MAPPING_KEY");
-
- /// Expect a value of an ordered mapping.
- static const FLOW_SEQUENCE_ENTRY_MAPPING_VALUE =
- const _State("FLOW_SEQUENCE_ENTRY_MAPPING_VALUE");
-
- /// Expect the and of an ordered mapping entry.
- static const FLOW_SEQUENCE_ENTRY_MAPPING_END =
- const _State("FLOW_SEQUENCE_ENTRY_MAPPING_END");
-
- /// Expect the first key of a flow mapping.
- static const FLOW_MAPPING_FIRST_KEY = const _State("FLOW_MAPPING_FIRST_KEY");
-
- /// Expect a key of a flow mapping.
- static const FLOW_MAPPING_KEY = const _State("FLOW_MAPPING_KEY");
-
- /// Expect a value of a flow mapping.
- static const FLOW_MAPPING_VALUE = const _State("FLOW_MAPPING_VALUE");
-
- /// Expect an empty value of a flow mapping.
- static const FLOW_MAPPING_EMPTY_VALUE =
- const _State("FLOW_MAPPING_EMPTY_VALUE");
-
- /// Expect nothing.
- static const END = const _State("END");
-
- final String name;
-
- const _State(this.name);
-
- String toString() => name;
-}
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