nim-json-serialization/tests
Jordan Hrycaj 3509706517
Lazy JSON parser (#42)
* Proper error handling when parsed number exceeds uint64

details:
  Returns an "errNonPortableInt" error

* need legacy flag for unit tests

* lazy numeric token parser

why:
  Numeric data may have a custom format. In particular,numeric data may be
  Uint256 which is not a JSON standard and might lead to an overflow.

details:
  Numeric values are assigned a preliminary token type tkNumeric without
  being fully parsed. This can be used to insert a custom parser.
  Otherwise the value is parsed implicitly when querying/fetching the
  token type.

  + tok:     replaced by getter tok() resolving lazy stuff (if necessary)
  + tokKind: current type without auto-resolving

  This lazy scheme could be extended to other custom types as long as
  the first token letter determines the custom type.

* activate lazy parsing in reader

howto:
  + no code change if a custom reader refers to an existing reader
    type FancyInt = distinct int
    proc readValue(reader: var JsonReader, value: var FancyInt) =
      value = reader.readValue(int).FancyInt

  + bespoke reader for cusom parsing
    type FancyUint = distinct uint
    proc readValue(reader: var JsonReader, value: var FancyUint) =
      if reader.lexer.lazyTok == tkNumeric:
        var accu: FancyUint
        reader.lexer.customIntValueIt:
          accu = accu * 10 + it.u256
        value = accu
      elif reader.lexer.tok == tkString:
        value = reader.lexer.strVal.parseUint.FancyUint
        ...
      reader.lexer.next

  + full code explanation at json_serialisation/reader.readValue()

* Add lazy parsing for customised string objects

why:
  This allows parsing large or specialised strings without storing it
  in the lexer state descriptor.

details:
  Similar logic applies as for the cusomised number parser. For mostly
  all practical cases, a DSL template is available serving as wrapper
  around the character/byte item processor code.

* fix typo in unit test
2022-05-05 17:33:40 +01:00
..
cases add github action 2020-12-24 16:04:58 +07:00
nim.cfg add "--threads:on" to tests 2019-01-11 15:33:32 +02:00
test_all.nim Update the lexer test and add it to nimble test 2020-03-25 18:43:56 +02:00
test_json_flavor.nim Add support for serialization flavors 2021-03-18 13:01:06 +02:00
test_lexer.nim Enable styleCheck:usages 2021-12-15 13:17:38 +02:00
test_serialization.nim Lazy JSON parser (#42) 2022-05-05 17:33:40 +01:00
utils.nim Enable styleCheck:usages 2021-12-15 13:17:38 +02:00