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discard """
output: '''{"foo":{"test":"123"}}'''
"""
import json, options
type
Foo = ref object
test: string
Test = object
foo: Option[Foo]
let js = """{"foo": {"test": "123"}}"""
let parsed = parseJson(js)
let a = parsed.to(Test)
echo $(%*a)
# RefPerson is used to test that overloaded `==` operator is not called by
# options. It is defined here in the global scope, because otherwise the test
# will not even consider the `==` operator. Different bug?
type RefPerson = ref object
name: string
proc `==`(a, b: RefPerson): bool =
assert(not a.isNil and not b.isNil)
a.name == b.name
block options:
# work around a bug in unittest
let intNone = none(int)
let stringNone = none(string)
block example:
proc find(haystack: string, needle: char): Option[int] =
for i, c in haystack:
if c == needle:
return some i
doAssert("abc".find('c').get() == 2)
let result = "team".find('i')
doAssert result == intNone
doAssert result.isNone
block some:
doAssert some(6).get() == 6
doAssert some("a").unsafeGet() == "a"
doAssert some(6).isSome
doAssert some("a").isSome
block none:
doAssertRaises UnpackDefect:
discard none(int).get()
doAssert(none(int).isNone)
doAssert(not none(string).isSome)
block equality:
doAssert some("a") == some("a")
doAssert some(7) != some(6)
doAssert some("a") != stringNone
doAssert intNone == intNone
when compiles(some("a") == some(5)):
doAssert false
when compiles(none(string) == none(int)):
doAssert false
block get_with_a_default_value:
doAssert(some("Correct").get("Wrong") == "Correct")
doAssert(stringNone.get("Correct") == "Correct")
block stringify:
doAssert($(some("Correct")) == "Some(\"Correct\")")
doAssert($(stringNone) == "None[string]")
block map_with_a_void_result:
var procRan = 0
some(123).map(proc (v: int) = procRan = v)
doAssert procRan == 123
intNone.map(proc (v: int) = doAssert false)
block map:
doAssert(some(123).map(proc (v: int): int = v * 2) == some(246))
doAssert(intNone.map(proc (v: int): int = v * 2).isNone)
block filter:
doAssert(some(123).filter(proc (v: int): bool = v == 123) == some(123))
doAssert(some(456).filter(proc (v: int): bool = v == 123).isNone)
doAssert(intNone.filter(proc (v: int): bool = doAssert false).isNone)
block flatMap:
proc addOneIfNotZero(v: int): Option[int] =
if v != 0:
result = some(v + 1)
else:
result = none(int)
doAssert(some(1).flatMap(addOneIfNotZero) == some(2))
doAssert(some(0).flatMap(addOneIfNotZero) == none(int))
doAssert(some(1).flatMap(addOneIfNotZero).flatMap(addOneIfNotZero) == some(3))
proc maybeToString(v: int): Option[string] =
if v != 0:
result = some($v)
else:
result = none(string)
doAssert(some(1).flatMap(maybeToString) == some("1"))
proc maybeExclaim(v: string): Option[string] =
if v != "":
result = some v & "!"
else:
result = none(string)
doAssert(some(1).flatMap(maybeToString).flatMap(maybeExclaim) == some("1!"))
doAssert(some(0).flatMap(maybeToString).flatMap(maybeExclaim) == none(string))
block SomePointer:
var intref: ref int
doAssert(option(intref).isNone)
intref.new
doAssert(option(intref).isSome)
let tmp = option(intref)
doAssert(sizeof(tmp) == sizeof(ptr int))
var prc = proc (x: int): int = x + 1
doAssert(option(prc).isSome)
prc = nil
doAssert(option(prc).isNone)
block:
doAssert(none[int]().isNone)
doAssert(none(int) == none[int]())
# "$ on typed with .name"
block:
type Named = object
name: string
let nobody = none(Named)
doAssert($nobody == "None[Named]")
# "$ on type with name()"
block:
type Person = object
myname: string
let noperson = none(Person)
doAssert($noperson == "None[Person]")
# "Ref type with overloaded `==`"
block:
let p = some(RefPerson.new())
doAssert p.isSome
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