# NimYAML - YAML implementation in Nim # (c) Copyright 2015 Felix Krause # # See the file "copying.txt", included in this # distribution, for details about the copyright. type DumperState = enum dBlockExplicitMapKey, dBlockExplicitMapValue, dBlockImplicitMapKey, dBlockImplicitMapValue, dBlockSequenceItem, dFlowImplicitMapKey, dFlowImplicitMapValue, dFlowExplicitMapKey, dFlowExplicitMapValue, dFlowSequenceItem, dFlowImplicitMapStart, dFlowExplicitMapStart, dFlowSequenceStart proc needsEscaping(scalar: string): bool {.raises: [].} = scalar.len == 0 or scalar.find({'{', '}', '[', ']', ',', '#', '-', ':', '?', '%', '\x0A', '\c'}) != -1 proc writeDoubleQuoted(scalar: string, s: Stream) {.raises: [YamlPresenterOutputError].} = try: s.write('"') for c in scalar: if c == '"': s.write('\\') s.write(c) s.write('"') except: var e = newException(YamlPresenterOutputError, "") e.cause = getCurrentException() raise e template safeWrite(s: string or char) {.dirty.} = try: target.write(s) except: var e = newException(YamlPresenterOutputError, "") e.cause = getCurrentException() raise e proc startItem(target: Stream, style: YamlPresentationStyle, indentation: int, state: var DumperState) {.raises: [YamlPresenterOutputError].} = try: case state of dBlockExplicitMapValue: target.write('\x0A') target.write(repeat(' ', indentation)) target.write("? ") state = dBlockExplicitMapKey of dBlockExplicitMapKey: target.write('\x0A') target.write(repeat(' ', indentation)) target.write(": ") state = dBlockExplicitMapValue of dBlockImplicitMapValue: target.write('\x0A') target.write(repeat(' ', indentation)) state = dBlockImplicitMapKey of dBlockImplicitMapKey: target.write(": ") state = dBlockImplicitMapValue of dFlowExplicitMapKey: target.write('\x0A') target.write(repeat(' ', indentation)) target.write(": ") state = dFlowExplicitMapValue of dFlowExplicitMapValue: target.write(",\x0A") target.write(repeat(' ', indentation)) target.write("? ") state = dFlowExplicitMapKey of dFlowImplicitMapStart: if style == ypsJson: target.write("\x0A") target.write(repeat(' ', indentation)) state = dFlowImplicitMapKey of dFlowExplicitMapStart: target.write('\x0A') target.write(repeat(' ', indentation)) target.write("? ") state = dFlowExplicitMapKey of dFlowImplicitMapKey: target.write(": ") state = dFlowImplicitMapValue of dFlowImplicitMapValue: if style == ypsJson: target.write(",\x0A") target.write(repeat(' ', indentation)) else: target.write(", ") state = dFlowImplicitMapKey of dBlockSequenceItem: target.write('\x0A') target.write(repeat(' ', indentation)) target.write("- ") of dFlowSequenceStart: case style of ypsMinimal, ypsDefault: discard of ypsCanonical, ypsJson: target.write('\x0A') target.write(repeat(' ', indentation)) of ypsBlockOnly: discard # can never happen state = dFlowSequenceItem of dFlowSequenceItem: case style of ypsMinimal, ypsDefault: target.write(", ") of ypsCanonical, ypsJson: target.write(",\x0A") target.write(repeat(' ', indentation)) of ypsBlockOnly: discard # can never happen except: var e = newException(YamlPresenterOutputError, "") e.cause = getCurrentException() raise e proc writeTagAndAnchor(target: Stream, tag: TagId, tagLib: YamlTagLibrary, anchor: AnchorId) {.raises:[YamlPresenterOutputError].} = try: if tag notin [yTagQuestionMark, yTagExclamationMark]: let tagUri = tagLib.uri(tag) if tagUri.startsWith(tagLib.secondaryPrefix): target.write("!!") target.write(tagUri[18..^1]) target.write(' ') elif tagUri.startsWith("!"): target.write(tagUri) target.write(' ') else: target.write("!<") target.write(tagUri) target.write("> ") if anchor != yAnchorNone: target.write("&") # TODO: properly select an anchor target.write(cast[byte]('a') + cast[byte](anchor)) target.write(' ') except: var e = newException(YamlPresenterOutputError, "") e.cause = getCurrentException() raise e proc present*(s: YamlStream, target: Stream, tagLib: YamlTagLibrary, style: YamlPresentationStyle = ypsDefault, indentationStep: int = 2) = var cached = initQueue[YamlStreamEvent]() cacheIterator = iterator(): YamlStreamEvent = while true: while cached.len > 0: yield cached.dequeue() try: let item = s() if finished(s): break cached.enqueue(item) except: var e = newException(YamlPresenterStreamError, "") e.cause = getCurrentException() raise e indentation = 0 levels = newSeq[DumperState]() for item in cacheIterator(): case item.kind of yamlStartDocument: if style != ypsJson: # TODO: tag directives try: target.write("%YAML 1.2\x0A") if tagLib.secondaryPrefix != yamlTagRepositoryPrefix: target.write("%TAG !! " & tagLib.secondaryPrefix & '\x0A') target.write("--- ") except: var e = newException(YamlPresenterOutputError, "") e.cause = getCurrentException() raise e of yamlScalar: if levels.len == 0: if style != ypsJson: safeWrite('\x0A') else: startItem(target, style, indentation, levels[levels.high]) if style != ypsJson: writeTagAndAnchor(target, item.scalarTag, tagLib, item.scalarAnchor) if style == ypsJson: if item.scalarTag in [yTagQuestionMark, yTagBoolean] and item.scalarType in [yTypeBoolTrue, yTypeBoolFalse]: if item.scalarType == yTypeBoolTrue: safeWrite("true") else: safeWrite("false") elif item.scalarTag in [yTagQuestionMark, yTagNull] and item.scalarType == yTypeNull: safeWrite("null") elif item.scalarTag in [yTagQuestionMark, yTagFloat] and item.scalarType in [yTypeFloatInf, yTypeFloatNaN]: raise newException(YamlPresenterJsonError, "Infinity and not-a-number values cannot be presented as JSON!") else: safeWrite(item.scalarContent) elif style == ypsCanonical or item.scalarContent.needsEscaping or (style == ypsJson and (item.scalarTag notin [yTagQuestionMark, yTagInteger, yTagFloat, yTagBoolean, yTagNull] or (item.scalarTag == yTagQuestionMark and item.scalarType notin [yTypeBoolFalse, yTypeBoolTrue, yTypeInteger, yTypeFloat, yTypeNull]))): writeDoubleQuoted(item.scalarContent, target) else: safeWrite(item.scalarContent) of yamlAlias: assert levels.len > 0 startItem(target, style, indentation, levels[levels.high]) try: target.write('*') target.write(cast[byte]('a') + cast[byte](item.aliasTarget)) except: var e = newException(YamlPresenterOutputError, "") e.cause = getCurrentException() raise e of yamlStartSequence: var nextState: DumperState case style of ypsDefault: var length = 0 while true: try: let next = s() assert (not finished(s)) cached.enqueue(next) case next.kind of yamlScalar: length += 2 + next.scalarContent.len of yamlAlias: length += 6 of yamlEndSequence: break else: length = int.high break except: var e = newException(YamlPresenterStreamError, "") e.cause = getCurrentException() raise e nextState = if length <= 60: dFlowSequenceStart else: dBlockSequenceItem of ypsJson: if levels[levels.high] in [dFlowImplicitMapStart, dFlowImplicitMapValue]: raise newException(YamlPresenterJsonError, "Cannot have sequence as map key in JSON output!") nextState = dFlowSequenceStart of ypsMinimal, ypsCanonical: nextState = dFlowSequenceStart of ypsBlockOnly: nextState = dBlockSequenceItem if levels.len == 0: if nextState == dBlockSequenceItem: if style != ypsJson: writeTagAndAnchor(target, item.seqTag, tagLib, item.seqAnchor) else: if style != ypsJson: writeTagAndAnchor(target, item.seqTag, tagLib, item.seqAnchor) safeWrite('\x0A') indentation += indentationStep else: startItem(target, style, indentation, levels[levels.high]) if style != ypsJson: writeTagAndAnchor(target, item.seqTag, tagLib, item.seqAnchor) indentation += indentationStep if nextState == dFlowSequenceStart: safeWrite('[') if levels.len > 0 and style in [ypsJson, ypsCanonical] and levels[levels.high] in [dBlockExplicitMapKey, dBlockExplicitMapValue, dBlockImplicitMapKey, dBlockImplicitMapValue, dBlockSequenceItem]: indentation += indentationStep levels.add(nextState) of yamlStartMap: var nextState: DumperState case style of ypsDefault: var length = 0 while true: try: let next = s() assert (not finished(s)) cached.enqueue(next) case next.kind of yamlScalar: length += 2 + next.scalarContent.len of yamlAlias: length += 6 of yamlEndMap: break else: length = int.high break except: var e = newException(YamlPresenterStreamError, "") e.cause = getCurrentException() raise e nextState = if length <= 60: dFlowImplicitMapStart else: if item.mapMayHaveKeyObjects: dBlockExplicitMapValue else: dBlockImplicitMapValue of ypsMinimal: nextState = if item.mapMayHaveKeyObjects: dFlowExplicitMapStart else: dFlowImplicitMapStart of ypsCanonical: nextState = dFlowExplicitMapStart of ypsJson: if levels.len > 0 and levels[levels.high] in [dFlowImplicitMapStart, dFlowImplicitMapValue]: raise newException(YamlPresenterJsonError, "Cannot have map as map key in JSON output!") nextState = dFlowImplicitMapStart of ypsBlockOnly: nextState = if item.mapMayHaveKeyObjects: dBlockExplicitMapValue else: dBlockImplicitMapValue if levels.len == 0: if nextState in [dBlockExplicitMapValue, dBlockImplicitMapValue]: if style != ypsJson: writeTagAndAnchor(target, item.mapTag, tagLib, item.mapAnchor) else: if style != ypsJson: safeWrite('\x0A') writeTagAndAnchor(target, item.mapTag, tagLib, item.mapAnchor) indentation += indentationStep else: if nextState in [dBlockExplicitMapValue, dBlockImplicitMapValue, dBlockImplicitMapKey]: if style != ypsJson: writeTagAndAnchor(target, item.mapTag, tagLib, item.mapAnchor) startItem(target, style, indentation, levels[levels.high]) else: startItem(target, style, indentation, levels[levels.high]) if style != ypsJson: writeTagAndAnchor(target, item.mapTag, tagLib, item.mapAnchor) indentation += indentationStep if nextState in [dFlowImplicitMapStart, dFlowExplicitMapStart]: safeWrite('{') if levels.len > 0 and style in [ypsJson, ypsCanonical] and levels[levels.high] in [dBlockExplicitMapKey, dBlockExplicitMapValue, dBlockImplicitMapKey, dBlockImplicitMapValue, dBlockSequenceItem]: indentation += indentationStep levels.add(nextState) of yamlEndSequence: assert levels.len > 0 case levels.pop() of dFlowSequenceItem: case style of ypsDefault, ypsMinimal, ypsBlockOnly: safeWrite(']') of ypsJson, ypsCanonical: indentation -= indentationStep try: target.write('\x0A') target.write(repeat(' ', indentation)) target.write(']') except: var e = newException(YamlPresenterOutputError, "") e.cause = getCurrentException() raise e if levels.len == 0 or levels[levels.high] notin [dBlockExplicitMapKey, dBlockExplicitMapValue, dBlockImplicitMapKey, dBlockImplicitMapValue, dBlockSequenceItem]: continue of dFlowSequenceStart: if levels.len > 0 and style in [ypsJson, ypsCanonical] and levels[levels.high] in [dBlockExplicitMapKey, dBlockExplicitMapValue, dBlockImplicitMapKey, dBlockImplicitMapValue, dBlockSequenceItem]: indentation -= indentationStep safeWrite(']') of dBlockSequenceItem: discard else: assert false indentation -= indentationStep of yamlEndMap: assert levels.len > 0 case levels.pop() of dFlowImplicitMapValue, dFlowExplicitMapValue: case style of ypsDefault, ypsMinimal, ypsBlockOnly: safeWrite('}') of ypsJson, ypsCanonical: indentation -= indentationStep try: target.write('\x0A') target.write(repeat(' ', indentation)) target.write('}') except: var e = newException(YamlPresenterOutputError, "") e.cause = getCurrentException() raise e if levels.len == 0 or levels[levels.high] notin [dBlockExplicitMapKey, dBlockExplicitMapValue, dBlockImplicitMapKey, dBlockImplicitMapValue, dBlockSequenceItem]: continue of dFlowImplicitMapStart, dFlowExplicitMapStart: if levels.len > 0 and style in [ypsJson, ypsCanonical] and levels[levels.high] in [dBlockExplicitMapKey, dBlockExplicitMapValue, dBlockImplicitMapKey, dBlockImplicitMapValue, dBlockSequenceItem]: indentation -= indentationStep safeWrite('}') of dBlockImplicitMapValue, dBlockExplicitMapValue: discard else: assert false indentation -= indentationStep of yamlEndDocument: try: let next = s() if finished(s): break cached.enqueue(next) except: var e = newException(YamlPresenterStreamError, "") e.cause = getCurrentException() raise e safeWrite("...\x0A") proc transform*(input: Stream, output: Stream, style: YamlPresentationStyle, indentationStep: int = 2) = var tagLib = extendedTagLibrary() parser = newParser(tagLib) present(parser.parse(input), output, tagLib, style, indentationStep)