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import streams
import strutils
import tables
type
Field* = ref object
label*: string
value*: string
Record* = ref object
fields: OrderedTableRef[string, seq[string]]
ParseState {.pure.} = enum
Initial
Comment
Label
Value
ValueSkipSpace
FieldReady
RecParser* = ref object
state: ParseState
field: Field
record: Record
RecParseError* = object of Exception
const
LabelFirstChar = {'a'..'z', 'A'..'Z', '%'}
LabelChar = {'a'..'z', 'A'..'Z', '0'..'9', '_'}
EofMarker = '\0'
proc newRecParser*(): RecParser =
new(result)
result.state = ParseState.Initial
proc newField(): Field =
new(result)
result.label = ""
result.value = ""
proc newField(label, value: string): Field =
new(result)
result.label = label
result.value = value
proc newRecord(): Record =
new(result)
result.fields = newOrderedTable[string, seq[string]]()
proc feed*(parser: RecParser, ch: char, record: var Record): bool =
while true:
case parser.state
of ParseState.Initial:
case ch
of '#':
parser.state = ParseState.Comment
of '\l', EofMarker:
if parser.record != nil:
result = true
record = parser.record
parser.record = nil
of LabelFirstChar:
parser.state = ParseState.Label
parser.field = newField()
parser.field.label &= ch
else:
raise newException(RecParseError, "parse error: expected a comment, a label or an empty line")
of ParseState.Comment:
case ch
of '\l':
parser.state = ParseState.Initial
else: discard
of ParseState.Label:
case ch
of ':':
parser.state = ParseState.ValueSkipSpace
of LabelChar:
parser.field.label &= ch
else:
raise newException(RecParseError,
"parse error: invalid label char: " & ch)
of ParseState.Value:
case ch
of '\l':
let valueLen = len(parser.field.value)
if valueLen > 0 and parser.field.value[valueLen-1] == '\\':
setLen(parser.field.value, valueLen - 1)
else:
parser.state = ParseState.FieldReady
of EofMarker:
raise newException(RecParseError,
"parse error: value must be terminated by a newline")
else:
parser.field.value &= ch
of ParseState.ValueSkipSpace:
case ch
of (WhiteSpace - NewLines):
discard
else:
parser.field.value &= ch
parser.state = ParseState.Value
of ParseState.FieldReady:
case ch
of '+':
parser.state = ParseState.ValueSkipSpace
parser.field.value &= '\l'
else:
if parser.record == nil:
parser.record = newRecord()
if hasKey(parser.record.fields, parser.field.label):
add(parser.record.fields[parser.field.label], parser.field.value)
else:
add(parser.record.fields, parser.field.label,
@[parser.field.value])
parser.field = nil
parser.state = ParseState.Initial
continue
break
proc `[]`*(record: Record, label: string): string =
result = record.fields[label][0]
proc len*(record: Record): int =
result = len(record.fields)
iterator records*(stream: Stream): Record =
let parser = newRecParser()
var record: Record
while true:
var ch = readChar(stream)
if feed(parser, ch, record):
yield record
if ch == EofMarker:
break
iterator pairs*(record: Record): (string, string) =
for label, values in record.fields:
for value in values:
yield (label, value)
iterator items*(record: Record): Field =
for label, value in record:
yield newField(label, value)
proc hasField*(record: Record, label: string): bool =
for field in record:
if field.label == label:
return true
proc contains*(record: Record, label: string): bool =
result = hasField(record, label)
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