require "../spec_helper"

include Parcom

# defining my own JSON alias in case of strange interactions
# with the built-in type
alias JSONValue = Nil \
                | Bool \
                | Int64 \
                | Float64 \
                | String \
                | Array(JSONValue) \
                | Hash(String, JSONValue)

def json_null
  Parser.token_sequence("null".chars).map { |_| nil.as(JSONValue) }
end
 
def json_value : Parser(Char, JSONValue)
  Parser.first_of([
    json_null,
  ])
end

describe "example: JSON parsing" do
  describe "json_null" do
    it "parses the string 'null' and returns nil when successful" do
      result = json_null.parse(Tokens.from_string("null"))
      result.value.should be_nil
      result.tokens.empty?.should be_true

      expect_raises(ParserFail) { json_null.parse(Tokens.from_string("")) }
    end
  end

  describe "json_value" do
    it "parses null" do
      result = json_value.parse(Tokens.from_string("null"))
      result.value.should be_nil
      result.tokens.empty?.should be_true
    end
  end
end