status-lib/status/libstatus/edn_helpers.nim

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Nim
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2021-09-08 18:05:39 +00:00
import typetraits
import edn, chronicles
import ../types/[sticker] # FIXME: there should be no type deps
# forward declaration:
proc parseNode[T](node: EdnNode, searchName: string): T
proc parseMap[T](map: HMap, searchName: string,): T
proc getValueFromNode[T](node: EdnNode): T =
if node.kind == EdnSymbol:
when T is string:
result = node.symbol.name
elif node.kind == EdnKeyword:
when T is string:
result = node.keyword.name
elif node.kind == EdnString:
when T is string:
result = node.str
elif node.kind == EdnCharacter:
when T is string:
result = node.character
elif node.kind == EdnBool:
when T is bool:
result = node.boolVal
elif node.kind == EdnInt:
when T is int:
try:
result = cast[int](node.num)
except:
warn "Returned 0 value for node, when value should have been ", val = $node.num
result = 0
else:
raise newException(ValueError, "couldn't get '" & T.type.name & "'value from node: " & repr(node))
proc parseVector[T: seq[Sticker]](node: EdnNode, searchName: string): seq[Sticker] =
# TODO: make this generic to accept any seq[T]. Issue is that instantiating result
# like `result = T()` is not allowed when T is `seq[Sticker]`
# because seq[Sticker] isn't an object, whereas it works when T is
# an object type (like Sticker). IOW, Sticker is an object type, but seq[Sticker]
# is not
result = newSeq[Sticker]()
for i in 0..<node.vec.len:
var sticker: Sticker = Sticker()
let child = node.vec[i]
if child.kind == EdnMap:
for k, v in sticker.fieldPairs:
v = parseMap[v.type](child.map, k)
result.add(sticker)
proc parseMap[T](map: HMap, searchName: string): T =
for iBucket in 0..<map.buckets.len:
let bucket = map.buckets[iBucket]
if bucket.len > 0:
for iChild in 0..<bucket.len:
let child = bucket[iChild]
let isRoot = child.key.kind == EdnSymbol and child.key.symbol.name == "meta"
if child.key.kind != EdnKeyword and not isRoot:
continue
if isRoot or child.key.keyword.name == searchName:
if child.value.kind == EdnMap:
result = parseMap[T](child.value.map, searchName)
break
elif child.value.kind == EdnVector:
when T is seq[Sticker]:
result = parseVector[T](child.value, searchName)
break
result = getValueFromNode[T](child.value)
break
proc parseNode[T](node: EdnNode, searchName: string): T =
if node.kind == EdnMap:
result = parseMap[T](node.map, searchName)
else:
result = getValueFromNode[T](node)
proc decode*[T](node: EdnNode): T =
result = T()
for k, v in result.fieldPairs:
v = parseNode[v.type](node, k)
proc decode*[T](edn: string): T =
decode[T](read(edn))