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Added sequential parser
This commit is contained in:
Felix Krause
parent
26c1c07567
commit
0544a8bba0
215
src/yaml/sequential.nim
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215
src/yaml/sequential.nim
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@ -0,0 +1,215 @@
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import streams, tables, strutils
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import private.lexer
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type
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YamlParserEventKind* = enum
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yamlStartDocument, yamlEndDocument, yamlStartMap, yamlEndMap,
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yamlStartSequence, yamlEndSequence, yamlScalar, yamlAlias,
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yamlError, yamlWarning
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YamlParserEvent* = ref object
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case kind*: YamlParserEventKind
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of yamlStartMap, yamlStartSequence:
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objAnchor* : string # may be nil, may not be empty
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objTag* : string # may not be nil or empty, is a complete URI.
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of yamlScalar:
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scalarAnchor* : string # may be nil
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scalarTag* : string # may not be nil, is a complete URI.
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scalarContent*: string # may not be nil (but empty)
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of yamlEndMap, yamlEndSequence, yamlStartDocument, yamlEndDocument:
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discard
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of yamlAlias:
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aliasName* : string # may not be nil nor empty
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of yamlError, yamlWarning:
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description* : string
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line* : int
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column* : int
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YamlParserState = enum
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ylInitial, ylSkipDirective, ylBlock, ylFlow
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OutcomeEnum = enum
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oOkay, oWarn, oContinue
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LevelKind = enum
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lUnknown, lSequence, lMap
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DocumentLevel = object
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kind: LevelKind
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indicatorColumn: int
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readKey: bool
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anchor: string
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tag: string
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template yieldWarning(d: string) {.dirty.} =
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yield YamlParserEvent(kind: yamlWarning, description: d,
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line: lex.line, column: lex.column)
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template yieldError(d: string) {.dirty.} =
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yield YamlParserEvent(kind: yamlError, description: d,
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line: lex.line, column: lex.column)
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template tag(): string {.dirty.} =
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if isNil(level.tag):
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case level.kind
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of lUnknown:
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result = "!!str"
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of lSequence:
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result = "!!seq"
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of lMap:
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result = "!!map"
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else:
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return level.tag
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template closeLevel() {.dirty.} =
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case level.kind
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of lUnknown:
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yield YamlParserEvent(kind: yamlScalar, scalarAnchor: level.anchor,
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scalarTag: tag(), scalarContent: "")
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of lSequence:
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yield YamlParserEvent(kind: yamlEndSequence)
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of lMap:
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yield YamlParserEvent(kind: yamlEndMap)
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template closeLevelsByIndicator() {.dirty.} =
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while levels.len > 0:
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let level = levels[levels.high]
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if level.indicatorColumn > lex.column:
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closeLevel()
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else:
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break
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levels.pop()
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iterator events*(input: Stream): YamlParserEvent =
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var
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state = ylInitial
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lex : YamlLexer
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foundYamlDirective = false
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tagShorthands = initTable[string, string]()
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levels = initSeq[DocumentLevel]()
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curIndentation: int
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lex.open(input)
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var nextToken = lexer.tokens
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var token = nextToken(lex)
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while not finished(nextToken):
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case state
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of ylInitial:
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case token.kind
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of yamlYamlDirective:
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if foundYamlDirective:
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yield YamlParserEvent(kind: yamlError,
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description: "Duplicate %YAML tag",
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line: lex.line,
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column: lex.column)
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state = ylSkipDirective
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else:
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var
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outcome = oOkay
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actualVersion = ""
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for version in [1, 2]:
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token = nextToken(lex)
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if finished(nextToken):
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yieldError("Missing or badly formatted YAML version")
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outcome = oContinue
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break
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if token.kind != yamlVersionPart:
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yieldError("Missing or badly formatted YAML version")
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outcome = oContinue
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break
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if parseInt(lex.content) != version:
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outcome = oWarn
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if actualVersion.len > 0: actualVersion &= "."
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actualVersion &= $version
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case outcome
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of oContinue:
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continue
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of oWarn:
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yieldWarning("Unsupported version: " & actualVersion &
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", trying to parse anyway")
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else:
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discard
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foundYamlDirective = true
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of yamlTagDirective:
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token = nextToken(lex)
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if finished(nextToken):
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yieldError("Incomplete %TAG directive")
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continue
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if token.kind != yamlTagHandle:
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yieldError("Invalid token (expected tag handle)")
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state = ylSkipDirective
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continue
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let tagHandle = lex.content
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token = nextToken(lex)
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if finished(nextToken):
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yieldError("Incomplete %TAG directive")
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continue
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if token.kind != yamlTagURI:
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yieldError("Invalid token (expected tag URI)")
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state = ylSkipDirective
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continue
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tagShorthands[tagHandle] = lex.content
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of yamlUnknownDirective:
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yieldWarning("Unknown directive: " & lex.content)
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state = ylSkipDirective
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of yamlComment:
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discard
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of yamlDirectivesEnd:
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yield YamlParserEvent(kind: yamlStartDocument)
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state = ylLineStart
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of yamlDocumentEnd:
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yield YamlParserEvent(kind: yamlStartDocument)
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yield YamlParserEvent(kind: yamlEndDocument)
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else:
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yield YamlParserEvent(kind: yamlStartDocument)
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state = ylLineStart
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continue
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of ylSkipDirective:
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if token.kind not in [yamlUnknownDirectiveParam, yamlTagHandle,
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yamlTagURI, yamlVersionPart, yamlComment]:
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state = ylInitial
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continue
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of ylBlock:
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case token.kind
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of yamlLineStart:
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discard
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of yamlDash:
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closeLevelsByIndicator()
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if levels.count > 0:
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let level = levels[levels.high]
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if level.kind == lUnknown:
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level.kind = lSequence
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level.indicatorColumn = lex.column
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levels.add(DocumentLevel(kind: lUnknown,
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indicatorColumn = -1,
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readKey: false,
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anchor: nil, tag: nil))
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elif level.indicatorColumn < lex.column:
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yieldError("Invalid indentation for '-'")
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elif level.kind == lSequence:
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levels.add(DocumentLevel(kind: lUnknown,
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indicatorColumn: -1,
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readKey: false,
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anchor: nil, tag: nil))
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else:
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yieldError("Unexpected token: '-'")
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else:
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levels.add(DocumentLevel(kind: lSequence,
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indicatorColumn: lex.column,
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readKey: false,
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anchor: nil, tag: nil))
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levels.add(DocumentLevel(kind: lUnknown,
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indicatorColmun: -1,
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readKey: false,
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anchor: nil, tag: nil))
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of yamlQuestionmark:
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of yamlColon:
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else:
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discard
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token = nextToken(lex)
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