Eminim — JSON deserialization macro for Nim
About
This package provides a to macro which deserializes the specified type from a Stream. It
generates code, in compile time, to use directly the JsonParser, without creating intermediate JsonNode(s).
For example:
type Foo = ref object
value: int
let s = newStringStream("{\"value\": 1}")
let a = s.to(Foo)Produces this code:
proc pack(s: Stream): Foo =
var p: JsonParser
open(p, s, "unknown file")
discard getTok(p)
new(result)
eat(p, tkCurlyLe)
while p.tok != tkCurlyRi:
if p.tok != tkString:
raiseParseErr(p, "string literal as key")
let key = move(p.a)
discard getTok(p)
eat(p, tkColon)
case key
of "value":
if p.tok == tkInt:
result.value = int(parseInt(p.a))
discard getTok(p)
else:
raiseParseErr(p, "int")
else:
raiseParseErr(p, "object field")
if p.tok != tkComma:
break
discard getTok(p)
eat(p, tkCurlyRi)
eat(p, tkEof)
close(p)
pack(s)
