NimYAML/private/streams.nim

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# 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 IteratorYamlStream = ref object of YamlStream
backend: iterator(): YamlStreamEvent
proc initYamlStream*(backend: iterator(): YamlStreamEvent): YamlStream =
result = new(IteratorYamlStream)
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result.peeked = false
result.isFinished = false
IteratorYamlStream(result).backend = backend
result.nextImpl = proc(s: YamlStream, e: var YamlStreamEvent): bool =
e = IteratorYamlStream(s).backend()
if finished(IteratorYamlStream(s).backend):
s.isFinished = true
result = false
else: result = true
proc next*(s: YamlStream): YamlStreamEvent =
yAssert(not s.isFinished)
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if s.peeked:
s.peeked = false
shallowCopy(result, s.cached)
else:
try:
while true:
if s.nextImpl(s, result): break
yAssert(not s.isFinished)
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except YamlStreamError:
let cur = getCurrentException()
var e = newException(YamlStreamError, cur.msg)
e.parent = cur.parent
raise e
except Exception:
let cur = getCurrentException()
var e = newException(YamlStreamError, cur.msg)
e.parent = cur
raise e
proc peek*(s: YamlStream): YamlStreamEvent =
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if not s.peeked:
s.cached = s.next()
s.peeked = true
shallowCopy(result, s.cached)
proc `peek=`*(s: YamlStream, value: YamlStreamEvent) =
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s.cached = value
s.peeked = true
proc finished*(s: YamlStream): bool =
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if s.peeked: result = false
else:
try:
while true:
if s.isFinished: return true
if s.nextImpl(s, s.cached):
s.peeked = true
return false
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except YamlStreamError:
let cur = getCurrentException()
var e = newException(YamlStreamError, cur.msg)
e.parent = cur.parent
raise e
except Exception:
let cur = getCurrentException()
echo cur.getStackTrace()
var e = newException(YamlStreamError, cur.msg)
e.parent = cur
raise e