mirror of https://github.com/status-im/NimYAML.git
513 lines
21 KiB
Nim
513 lines
21 KiB
Nim
# NimYAML - YAML implementation in Nim
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# (c) Copyright 2015 Felix Krause
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#
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# See the file "copying.txt", included in this
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# distribution, for details about the copyright.
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import typetraits
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type
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DumperState = enum
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dBlockExplicitMapKey, dBlockImplicitMapKey, dBlockMapValue,
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dBlockInlineMap, dBlockSequenceItem, dFlowImplicitMapKey, dFlowMapValue,
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dFlowExplicitMapKey, dFlowSequenceItem, dFlowMapStart,
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dFlowSequenceStart
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proc needsEscaping(scalar: string): bool {.raises: [].} =
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scalar.len == 0 or scalar[0] in ['@', '`'] or
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scalar.find({'{', '}', '[', ']', ',', '#', '-', ':', '?', '%', '"',
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'\'', '\x0A', '\c'}) != -1
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proc writeDoubleQuoted(scalar: string, s: Stream)
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{.raises: [YamlPresenterOutputError].} =
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try:
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s.write('"')
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for c in scalar:
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if c == '"':
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s.write('\\')
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s.write(c)
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s.write('"')
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except:
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var e = newException(YamlPresenterOutputError, "")
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e.parent = getCurrentException()
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raise e
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template safeWrite(s: string or char) {.dirty.} =
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try:
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target.write(s)
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except:
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var e = newException(YamlPresenterOutputError, "")
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e.parent = getCurrentException()
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raise e
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proc startItem(target: Stream, style: PresentationStyle, indentation: int,
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state: var DumperState, isObject: bool)
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{.raises: [YamlPresenterOutputError].} =
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try:
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case state
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of dBlockMapValue:
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target.write('\x0A')
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target.write(repeat(' ', indentation))
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if isObject or style == psCanonical:
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target.write("? ")
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state = dBlockExplicitMapKey
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else:
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state = dBlockImplicitMapKey
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of dBlockInlineMap:
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state = dBlockImplicitMapKey
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of dBlockExplicitMapKey:
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target.write('\x0A')
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target.write(repeat(' ', indentation))
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target.write(": ")
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state = dBlockMapValue
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of dBlockImplicitMapKey:
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target.write(": ")
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state = dBlockMapValue
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of dFlowExplicitMapKey:
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if style != psMinimal:
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target.write('\x0A')
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target.write(repeat(' ', indentation))
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target.write(": ")
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state = dFlowMapValue
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of dFlowMapValue:
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if (isObject and style != psMinimal) or
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style in [psJson, psCanonical]:
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target.write(",\x0A" & repeat(' ', indentation))
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if style == psJson:
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state = dFlowImplicitMapKey
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else:
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target.write("? ")
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state = dFlowExplicitMapKey
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elif isObject and style == psMinimal:
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target.write(", ? ")
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state = dFlowExplicitMapKey
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else:
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target.write(", ")
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state = dFlowImplicitMapKey
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of dFlowMapStart:
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if (isObject and style != psMinimal) or
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style in [psJson, psCanonical]:
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target.write("\x0A" & repeat(' ', indentation))
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if style == psJson:
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state = dFlowImplicitMapKey
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else:
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target.write("? ")
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state = dFlowExplicitMapKey
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else:
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state = dFlowImplicitMapKey
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of dFlowImplicitMapKey:
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target.write(": ")
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state = dFlowMapValue
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of dBlockSequenceItem:
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target.write('\x0A')
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target.write(repeat(' ', indentation))
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target.write("- ")
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of dFlowSequenceStart:
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case style
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of psMinimal, psDefault:
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discard
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of psCanonical, psJson:
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target.write('\x0A')
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target.write(repeat(' ', indentation))
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of psBlockOnly:
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discard # can never happen
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state = dFlowSequenceItem
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of dFlowSequenceItem:
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case style
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of psMinimal, psDefault:
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target.write(", ")
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of psCanonical, psJson:
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target.write(",\x0A")
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target.write(repeat(' ', indentation))
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of psBlockOnly:
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discard # can never happen
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except:
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var e = newException(YamlPresenterOutputError, "")
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e.parent = getCurrentException()
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raise e
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proc writeTagAndAnchor(target: Stream, tag: TagId, tagLib: TagLibrary,
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anchor: AnchorId) {.raises:[YamlPresenterOutputError].} =
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try:
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if tag notin [yTagQuestionMark, yTagExclamationMark]:
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let tagUri = tagLib.uri(tag)
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if tagUri.startsWith(tagLib.secondaryPrefix):
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target.write("!!")
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target.write(tagUri[18..tagUri.high])
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target.write(' ')
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elif tagUri.startsWith("!"):
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target.write(tagUri)
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target.write(' ')
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else:
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target.write("!<")
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target.write(tagUri)
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target.write("> ")
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if anchor != yAnchorNone:
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target.write("&")
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# TODO: properly select an anchor
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target.write(cast[byte]('a') + cast[byte](anchor))
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target.write(' ')
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except:
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var e = newException(YamlPresenterOutputError, "")
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e.parent = getCurrentException()
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raise e
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proc present*(s: YamlStream, target: Stream, tagLib: TagLibrary,
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style: PresentationStyle = psDefault,
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indentationStep: int = 2) =
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var
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cached = initQueue[YamlStreamEvent]()
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cacheIterator = iterator(): YamlStreamEvent =
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while true:
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while cached.len > 0:
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yield cached.dequeue()
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try:
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let item = s()
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if finished(s):
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break
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cached.enqueue(item)
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except Exception:
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var e = newException(YamlPresenterStreamError, "")
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e.parent = getCurrentException()
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raise e
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indentation = 0
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levels = newSeq[DumperState]()
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for item in cacheIterator():
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case item.kind
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of yamlStartDocument:
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if style != psJson:
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# TODO: tag directives
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try:
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target.write("%YAML 1.2\x0A")
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if tagLib.secondaryPrefix != yamlTagRepositoryPrefix:
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target.write("%TAG !! " &
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tagLib.secondaryPrefix & '\x0A')
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target.write("--- ")
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except:
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var e = newException(YamlPresenterOutputError, "")
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e.parent = getCurrentException()
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raise e
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of yamlScalar:
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if levels.len == 0:
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if style != psJson:
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safeWrite('\x0A')
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else:
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startItem(target, style, indentation, levels[levels.high],
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false)
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if style != psJson:
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writeTagAndAnchor(target,
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item.scalarTag, tagLib, item.scalarAnchor)
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if style == psJson:
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let hint = guessType(item.scalarContent)
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if item.scalarTag in [yTagQuestionMark, yTagBoolean] and
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hint in [yTypeBoolTrue, yTypeBoolFalse]:
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if hint == yTypeBoolTrue:
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safeWrite("true")
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else:
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safeWrite("false")
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elif item.scalarTag in [yTagQuestionMark, yTagNull] and
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hint == yTypeNull:
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safeWrite("null")
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elif item.scalarTag in [yTagQuestionMark, yTagInteger] and
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hint == yTypeInteger:
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safeWrite(item.scalarContent)
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elif item.scalarTag in [yTagQuestionMark, yTagFloat] and
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hint in [yTypeFloatInf, yTypeFloatNaN]:
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raise newException(YamlPresenterJsonError,
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"Infinity and not-a-number values cannot be presented as JSON!")
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elif item.scalarTag in [yTagQuestionMark, yTagFloat] and
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hint == yTypeFloat:
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safeWrite(item.scalarContent)
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else:
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writeDoubleQuoted(item.scalarContent, target)
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elif style == psCanonical or item.scalarContent.needsEscaping:
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writeDoubleQuoted(item.scalarContent, target)
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else:
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safeWrite(item.scalarContent)
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of yamlAlias:
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if style == psJson:
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raise newException(YamlPresenterJsonError,
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"Alias not allowed in JSON output")
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assert levels.len > 0
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startItem(target, style, indentation, levels[levels.high], false)
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try:
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target.write('*')
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target.write(cast[byte]('a') + cast[byte](item.aliasTarget))
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except:
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var e = newException(YamlPresenterOutputError, "")
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e.parent = getCurrentException()
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raise e
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of yamlStartSequence:
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var nextState: DumperState
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case style
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of psDefault:
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var length = 0
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while true:
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try:
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let next = s()
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assert (not finished(s))
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cached.enqueue(next)
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case next.kind
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of yamlScalar:
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length += 2 + next.scalarContent.len
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of yamlAlias:
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length += 6
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of yamlEndSequence:
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break
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else:
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length = high(int)
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break
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except Exception:
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var e = newException(YamlPresenterStreamError, "")
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e.parent = getCurrentException()
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raise e
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nextState = if length <= 60: dFlowSequenceStart else:
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dBlockSequenceItem
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of psJson:
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if levels.len > 0 and levels[levels.high] in
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[dFlowMapStart, dFlowMapValue]:
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raise newException(YamlPresenterJsonError,
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"Cannot have sequence as map key in JSON output!")
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nextState = dFlowSequenceStart
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of psMinimal, psCanonical:
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nextState = dFlowSequenceStart
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of psBlockOnly:
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nextState = dBlockSequenceItem
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if levels.len == 0:
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if nextState == dBlockSequenceItem:
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if style != psJson:
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writeTagAndAnchor(target,
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item.seqTag, tagLib, item.seqAnchor)
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else:
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if style != psJson:
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writeTagAndAnchor(target,
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item.seqTag, tagLib, item.seqAnchor)
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safeWrite('\x0A')
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indentation += indentationStep
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else:
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startItem(target, style, indentation, levels[levels.high], true)
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if style != psJson:
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writeTagAndAnchor(target,
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item.seqTag, tagLib, item.seqAnchor)
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indentation += indentationStep
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if nextState == dFlowSequenceStart:
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safeWrite('[')
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if levels.len > 0 and style in [psJson, psCanonical] and
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levels[levels.high] in
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[dBlockExplicitMapKey, dBlockMapValue,
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dBlockImplicitMapKey, dBlockSequenceItem]:
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indentation += indentationStep
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levels.add(nextState)
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of yamlStartMap:
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var nextState: DumperState
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case style
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of psDefault:
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type mapParseState = enum
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mpInitial, mpKey, mpValue, mpNeedBlock
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var mps = mpInitial
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while mps != mpNeedBlock:
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try:
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let next = s()
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assert (not finished(s))
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cached.enqueue(next)
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case next.kind
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of yamlScalar, yamlAlias:
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case mps
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of mpInitial: mps = mpKey
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of mpKey: mps = mpValue
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else: mps = mpNeedBlock
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of yamlEndMap:
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break
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else:
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mps = mpNeedBlock
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except Exception:
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var e = newException(YamlPresenterStreamError, "")
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e.parent = getCurrentException()
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raise e
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nextState = if mps == mpNeedBlock: dBlockMapValue else:
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dBlockInlineMap
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of psMinimal:
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nextState = dFlowMapStart
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of psCanonical:
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nextState = dFlowMapStart
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of psJson:
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if levels.len > 0 and levels[levels.high] in
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[dFlowMapStart, dFlowMapValue]:
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raise newException(YamlPresenterJsonError,
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"Cannot have map as map key in JSON output!")
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nextState = dFlowMapStart
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of psBlockOnly:
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nextState = dBlockMapValue
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if levels.len == 0:
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if nextState == dBlockMapValue:
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if style != psJson:
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writeTagAndAnchor(target,
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item.mapTag, tagLib, item.mapAnchor)
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else:
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if style != psJson:
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safeWrite('\x0A')
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writeTagAndAnchor(target,
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item.mapTag, tagLib, item.mapAnchor)
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indentation += indentationStep
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else:
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if nextState in [dBlockMapValue, dBlockImplicitMapKey]:
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if style != psJson:
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writeTagAndAnchor(target,
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item.mapTag, tagLib, item.mapAnchor)
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startItem(target, style, indentation, levels[levels.high],
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true)
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else:
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startItem(target, style, indentation, levels[levels.high],
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true)
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if style != psJson:
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writeTagAndAnchor(target,
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item.mapTag, tagLib, item.mapAnchor)
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indentation += indentationStep
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if nextState == dFlowMapStart:
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safeWrite('{')
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if levels.len > 0 and style in [psJson, psCanonical] and
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levels[levels.high] in
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[dBlockExplicitMapKey, dBlockMapValue,
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dBlockImplicitMapKey, dBlockSequenceItem]:
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indentation += indentationStep
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levels.add(nextState)
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of yamlEndSequence:
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assert levels.len > 0
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case levels.pop()
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of dFlowSequenceItem:
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case style
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of psDefault, psMinimal, psBlockOnly:
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safeWrite(']')
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of psJson, psCanonical:
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indentation -= indentationStep
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try:
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target.write('\x0A')
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target.write(repeat(' ', indentation))
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target.write(']')
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except:
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var e = newException(YamlPresenterOutputError, "")
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e.parent = getCurrentException()
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raise e
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if levels.len == 0 or levels[levels.high] notin
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[dBlockExplicitMapKey, dBlockMapValue,
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dBlockImplicitMapKey, dBlockSequenceItem]:
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continue
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of dFlowSequenceStart:
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if levels.len > 0 and style in [psJson, psCanonical] and
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levels[levels.high] in
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[dBlockExplicitMapKey, dBlockMapValue,
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dBlockImplicitMapKey, dBlockSequenceItem]:
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indentation -= indentationStep
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safeWrite(']')
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of dBlockSequenceItem:
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discard
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else:
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assert false
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indentation -= indentationStep
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of yamlEndMap:
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assert levels.len > 0
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let level = levels.pop()
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case level
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of dFlowMapValue:
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case style
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of psDefault, psMinimal, psBlockOnly:
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safeWrite('}')
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of psJson, psCanonical:
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indentation -= indentationStep
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try:
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target.write('\x0A')
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target.write(repeat(' ', indentation))
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target.write('}')
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except:
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var e = newException(YamlPresenterOutputError, "")
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e.parent = getCurrentException()
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raise e
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if levels.len == 0 or levels[levels.high] notin
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[dBlockExplicitMapKey, dBlockMapValue,
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dBlockImplicitMapKey, dBlockSequenceItem]:
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continue
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of dFlowMapStart:
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if levels.len > 0 and style in [psJson, psCanonical] and
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levels[levels.high] in
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[dBlockExplicitMapKey, dBlockMapValue,
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dBlockImplicitMapKey, dBlockSequenceItem]:
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indentation -= indentationStep
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safeWrite('}')
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of dBlockMapValue, dBlockInlineMap:
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discard
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else:
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assert false
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indentation -= indentationStep
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of yamlEndDocument:
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try:
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let next = s()
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if finished(s):
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break
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cached.enqueue(next)
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except Exception:
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var e = newException(YamlPresenterStreamError, "")
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e.parent = getCurrentException()
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raise e
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safeWrite("...\x0A")
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proc transform*(input: Stream, output: Stream, style: PresentationStyle,
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indentationStep: int = 2) =
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var
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taglib = initExtendedTagLibrary()
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parser = newYamlParser(tagLib)
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events = parser.parse(input)
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try:
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if style == psCanonical:
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var specificTagEvents = iterator(): YamlStreamEvent =
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for e in events():
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var event = e
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case event.kind
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of yamlStartDocument, yamlEndDocument, yamlEndMap,
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yamlAlias, yamlEndSequence:
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discard
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of yamlStartMap:
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if event.mapTag in [yTagQuestionMark,
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yTagExclamationMark]:
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event.mapTag = yTagMap
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of yamlStartSequence:
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if event.seqTag in [yTagQuestionMark,
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yTagExclamationMark]:
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event.seqTag = yTagSequence
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of yamlScalar:
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if event.scalarTag == yTagQuestionMark:
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case guessType(event.scalarContent)
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of yTypeInteger:
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event.scalarTag = yTagInteger
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of yTypeFloat, yTypeFloatInf, yTypeFloatNaN:
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event.scalarTag = yTagFloat
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of yTypeBoolTrue, yTypeBoolFalse:
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event.scalarTag = yTagBoolean
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of yTypeNull:
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event.scalarTag = yTagNull
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of yTypeUnknown:
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event.scalarTag = yTagString
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elif event.scalarTag == yTagExclamationMark:
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event.scalarTag = yTagString
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yield event
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present(specificTagEvents, output, tagLib, style,
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indentationStep)
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else:
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present(events, output, tagLib, style, indentationStep)
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except YamlPresenterStreamError:
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let e = getCurrentException()
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if e.parent of IOError:
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raise cast[ref IOError](e.parent)
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elif e.parent of YamlParserError:
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raise cast[ref YamlParserError](e.parent)
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else:
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# never happens
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assert(false)
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except Exception:
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# compiler bug: https://github.com/nim-lang/Nim/issues/3772
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assert(false) |