▞ InterType
A JavaScript type checker with helpers to implement own types and do object shape validation.
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▞ InterType
Motivation
- structural typing
- inspired by Clojure spec[https://www.youtube.com/watch?v=B_Farscj0hY]
- most of the time used to perform a 'lower bounds' check of Plain Old Dictionaries (objects), i.e. objects
must satisfy all key/constraint checks of a given type declaration, but object may have additional
key/value pairs
Contracts of Type Tests and the Verbs isa
, validate
Type Tests
-
A type test (TT) is a function that accepts a single argument and returns a boolean.
-
TTs should not normally throw errors; however, that can sometimes be inconvenient to implement. For this
reason, InterType implements 'exception-guarding' which entails that should a type tester inadvertently
cause an exception, that exception will be silently caught and stored in the state.error
property of the
Intertype
instance; the return value of the call will be set false
. The following types nevah
and
oops
are almost equivalent in that they return false
for any input; however, immediately after using
oops
, the suppressed error may be accessed through types.state.error
property:
{ Intertype
Intertype_user_error } = require 'intertype'
types = new Intertype { errors: false, }
types.declare.nevah ( x ) -> false
types.declare.oops ( x ) -> throw new Error 'oops'
types.declare.oops_anyway ( x ) -> throw new Intertype_user_error 'oops'
types.isa.oops 42 # `false`
types.state.error? # `true` (i.e. `types.state.error` contains error)
types.isa.nevah 42 # `false`
types.state.error? # `false` (i.e. no error, all OK)
types.isa.oops_anyway 42 # !!! throws an error
Because silently suppressed errors can be tricky to debug and checking for state.error
is easily
forgotten (and should not normally be necessary), exception-guarding is an opt-in (as shown above, use
errors: false
)
-
Users may always construct type testers whose intentional errors will not be silently caught by deriving
their errors from Intertype_user_error
-
A type test must be idempotent and is therefore only allowed to look at, but not to touch (modify)
values; IOW, it must be a pure method in the sense of functional programming. Yes, in theory one could
write an isa
method that 'fixes' a list by transforming, adding or deleting some elements (conveniently
so, while one has to iterate over list elements anyway), but that would most certainly violate most user's
basic assumptions—a type check is not supposed to return with a triumphant 'does the value have the proper
shape? Well yes, now it does!'. A type check is not a repair order. InterType does not check for isa
method being pure because that is deemed (far) too computationally expensive.
isa
- However, when called in the context of a hedgerow as in
isa.collection.of.type x
, an exception may be
thrown, e.g. when a type name is undeclared or of
is preceded by a non-iterable type name (cf the
non-sensical isa.integer.of.integer 42
). This is not the type test, this is the verb isa
complaining
about a malformed chain of type tests. - It is not allowed to use a name in an
isa
(or validate
or create
) hedgerow without that name being
declare
d prior to that.
validate
validate
is a verb that performs an isa
test; should that return false
, an exception is thrown; if
it returns true
, the tested value will be returned.- convenient for writing postconditions, as in
f = ( a, b ) -> validate.integer a * b
.
Hedgerows
-
simplest form: test for a value; preferred form is to use property accessor syntax (a.k.a. 'dot
notation'), e.g. isa.integer x
(equivalent to isa[ 'integer' ] x
)
-
these accessors are called 'hedges'
-
hedges can be combined in so-called 'hedgerows', e.g. isa.positive0.integer x
tests whether x >= 0
-
hedgerows can be arbitrarily long, e.g. isa.optional.nonempty.list_of.optional.negative1.integer x
-
whether one wants lomng hedgerows or not is a matter of taste, but it will very probably be more
systematic and more readable to define meaningful intermediate types instead of using log hedgerows:
declare.xy_count { test: ( ( x ) -> @isa.optional.set_of.negative1.integer x ), }
declare.maybe_xy_counts { test: ( ( x ) -> @isa.optional.nonempty.list_of.xy_count x ), }
...
validate.maybe_xy_counts some_value
-
in order to satisfy a hedgerow constraint, the value given must satisfy all individual terms, in the order
given. In other words, a hedgerow is a notation for a series of terms connected by logical conjunctions,
a.b.c x ⇔ ( a x ) ∧ ( b x ) ∧ ( c x )
(in detail, list_of
and set_of
introduce a complication).
To re-use the slightly convoluted example from above, one can understand what
isa.optional.nonempty.list_of.optional.negative1.integer x
means by rewriting it in pseudo-code along
the following lines:
test: ( x ) ->
return false unless isa.optional x # `optional x` is satisfied if `x` is `undefined` or `null`, otherwise go on
return false unless isa.nonempty x # `nonempty x` is true if `x` contains at least one element
return false unless isa.list x # `list_of...` tests whether `x` is a list, ...
for each e in x: # ... and then applies the rest of the hedgerow to each of its elements:
return false unless isa.optional e # this `optional` clause is run against each element, so list may have `null` elements
return false unless isa.negative1 e # `negative1 x` tests for `x < 0`
return false unless isa.integer e # `true` for whole numbers; uses `Number.isInteger()`
return true
-
hedgerows will be evaluated in a 'short-circuited' manner like JavaScript logical operators; this means
that tests will only be performed up to the point where the result is definitely known. For example, if in
z = ( a or b )
the left sub-expression has been found to be true
, we already know that the outcome can
only be true
as well, so we don't have to compute b
. In isa.optional.text x
we find that x
is
undefined
or null
we are already done and can (and must) skip the test for text
. Conversely, if we'd
find that a
is false
the second part of the disjunction could still be true
, so we cannot
short-circuit but must evaluate the second part as well, and the same goes for isa.optional.text x
if
x?
(i.e. x != null
or, even more explicitly, (JS) ( x !== null ) and ( x !== undefined )
).
-
a hedgerow may contain one or more or
hedges that signify logical disjunction, e.g.
isa.integer.or.nonempty.text.or.boolean x
. In this case, we partition the hedgerow into its constituent
terms: ( integer x ) ∨ ( nonempty.text ) ∨ ( boolean x )
and evaluate by walking through each
sub-hedgerow until it is either satisfied (which is when we can break the loop) or dissatisfied; in that
case, we jump forward to the next sub-hedgerow to repeat the same; when there are no more sub-hedgerows
left, the very last test then determines the result for the entire row.
Diagram
isa.text
text is text isnt text
return true ATOERF¹
⊙ return true return false
¹ATOERF: Advance To OR, Else Return False
isa.text.or.optional.list_of.positive1.integer
text is text isnt text
return true ATOERF¹
or ————————————————————————
integer is integer isnt integer
next ATOERF¹
⊙ return true return false
¹ATOERF: Advance To OR, Else Return False
isa.text.or.optional.list_of.positive1.integer
text is text isnt text
return true ATOERF¹
or ————————————————————————
optional not x? x?
return true next
list_of: list is list isnt list
switch to EM² ATOERF¹
positive1 e > 0 not ( e > 0 )
next ATOERF¹
integer is integer isnt integer
next ATOERF¹
⊙ return true return false
¹ATOERF: Advance To OR, Else Return False
²EM: Elements Mode
Schema for isa.negative1.integer.or.optional.empty.text -42
(true
): Both isa.negative1 -42
and
isa.integer -42
evaluate to true
; since these terms are implicitly connected with and
, we must
evaluate them all to ensure no false
term occurs; this is what the single triangle ▼ signifies, 'continue
with next'. When we reach the or
clause, though, we can short-circuit (▼▼▼) the evaluation and return true
:
FALSE | isa | TRUE |
---|
| negative1 | ▼ |
| integer | ▼ |
───────── | OR | ▼▼▼────── |
| optional | |
| empty | |
| text | |
═════════ | ═════════ | ═════════ |
| -42 | TRUE |
Schema for isa.negative1.integer.or.optional.empty.text 'meep'
(false
): 'meep'
cannot satisfy
negative1
since it is not numeric, so the entire clause fails. We can again short-circuit, but only up to
the next or-clause, symbolized by ▼▼. The next term is optional
; since all values (including null
and
undefined
) satisfy this constraint, we go to the next term, empty
; since 'meep'.length
is 4
, this
term fails, so we have to ▼▼ advance to the end of the current clause which coincides with the end of the
hedgerow, meaning we can return false
:
FALSE | isa | TRUE |
---|
▼▼ | negative1 | |
| integer | |
────────▼ | OR | ───────── |
| optional | ▼ |
▼▼ | empty | |
| text | |
═════════ | ═════════ | ═════════ |
FALSE | 'meep' | |
Schema for isa.negative1.integer.or.optional.empty.text -42
(true
): null
is not negative (and, of
course, not positive either) so we can ▼▼ advance to the next 'gate'; there, null
does fulfill optional
(like any value) but with a 'special effect': isa.optional null
and isa.optional undefined
cause a
global short-circuit, meaning we can return true
right away and ignore any number of other constraints:
FALSE | isa | TRUE |
---|
▼▼ | negative1 | |
| integer | |
────────▼ | OR | ───────── |
| optional | ▼▼▼ |
| empty | |
| text | |
═════════ | ═════════ | ═════════ |
| null | TRUE |
This short-circuiting behavior of optional
when seeing a nullish value is peculiar to optional
; it is
similar to there only being a single empty exemplar of collections (strings, lists, sets) except applying to
all types: ( isa.empty.text a ) == ( isa.empty.text b )
entails a == b == ''
; likewise, ( isa.optional.$TYPE_A a ) == ( isa.optional.$TYPE_B b )
in conjunction with ( a == null )
implies a == b
, so as soon as we learn that a == null
and a value has an optional
allowance, no other constraint has
to be considered.
Note on optional
: The types optional.integer
and optional.text
have { null, undefined }
as
intersection of their domains, meaning that in the case of their disjunction—isa.optional.integer.or.text
,
isa.integer.or.optional.text
and so on—are indistinguishable: all variations will, among (infinitely many)
other values accept all of null
, undefined
, 1
, 42
, 'x'
, 'foobar'
and so on. Because of this one
may want to restrict oneself to only allow optional
as the first hedge, avoiding constructs like
isa.integer.or.optional.text
as a matter of style.
Schema for isa.nonempty.text.or.list_of.nonempty.text [ 'helo', 'world', ]
(true
): nonempty
gives
true
for [ 'helo', 'world', ]
, but since this is a list
rather than a text
, the first clause fails
nonetheless. Next up is list_of
, which first calls isa.list [ 'helo', 'world', ]
; that being true, it
then switches to element mode, meaning that rather than applaying the remaining tests against the argument
passed in (the list), they will be applied to each element of the collection; this is here symbolized by
∈ nonempty
and ∈ text
; in total, four tests will be performed: isa.nonempty 'helo'
, isa.text 'helo'
,
isa.nonempty 'world'
, and isa.text 'world'
, all of which return true
, which leads to the entire
compound type being satisfied:
FALSE | isa | TRUE |
---|
| nonempty | ▼ |
▼▼ | text | |
────────▼ | OR | ───────── |
| list_of | ▼ |
| ∈ nonempty | ▼ |
| ∈ text | ▼ |
═════════ | ═════════ | ═════════ |
| [ 'helo', 'world', ] | TRUE |
Observe that in a compound type, once the mode has been switched to element testing mode ∈
, there's no
going back, so isa.list_of.text.or.integer
is fundamentally different from isa.integer.or.list_of.text
:
the first will be true for all lists that contain nothing but strings and integer numbers, the second will
be true for all values that are either an integer or a list of zero or more strings. This is a shortcoming
of the current algorithm and may be fixed in the future; currently, there's no way to write ( isa.set_of.text x ) or ( isa.list_of.text x )
in a single go. Should you need such a type, it will probably
be best to give the type a name, as in
declare.set_or_list test: ( x ) -> ( isa.set_of.text x ) or ( isa.list_of.text x )
...
isa.nonempty.set_or_list [ 'a', 'b', ] # true
isa.set_or_list.or.integer 123 # true
xxx
types.isa.integer 42
types.isa.even.integer -42
types.isa.odd.integer 41
types.isa.negative1.integer -42
types.isa.negative0.integer 0
types.isa.positive1.integer 42
types.isa.positive0.integer 0
types.isa.list_of.integer [ 42, ]
types.isa.nonempty.list_of.negative1.integer [ -42, ]
types.isa.nonempty.list_of.negative0.integer [ 0, ]
types.isa.nonempty.list_of.positive1.integer [ 42, ]
types.isa.nonempty.list_of.positive0.integer [ 0, ]
types.isa.empty.list_of.integer []
types.isa.nonempty.list_of.integer [ 42, ]
types.isa.optional.integer 42
types.isa.optional.list_of.integer [ 42, ]
types.isa.optional.empty.list_of.integer []
types.isa.optional.nonempty.list_of.integer [ 42, ]
types.isa.optional.negative1.integer -42
types.isa.optional.negative0.integer 0
types.isa.optional.positive1.integer 42
types.isa.optional.positive0.integer 0
types.isa.optional.nonempty.list_of.negative1.integer [ -42, ]
types.isa.optional.nonempty.list_of.negative0.integer [ 0, ]
types.isa.optional.nonempty.list_of.positive1.integer [ 42, ]
types.isa.optional.nonempty.list_of.positive0.integer [ 0, ]
types.isa.optional.empty.list_of.negative1.integer -42
types.isa.optional.empty.list_of.negative0.integer 0
types.isa.optional.empty.list_of.positive1.integer 42
types.isa.optional.empty.list_of.positive0.integer 0
[all] [all] [isa_collection] [isa_collection] [isa_numeric] [isa_numeric] [mandatory]
————————————————————————————————————————————————————————————————————————————————————————————————————
isa optional empty list_of even negative0 <type>
validate nonempty odd negative1
positive0
positive1
Intertype state
Property
-
Intertype
instances have a state
property
-
the shape and initial value of types.state
is:
types.state = {
method: null
hedges: []
extra_keys: null
error: null
data: null }
-
The initial value of types.state
is resumed right before a top-level isa
or validate
test is
performed.
-
The fields of types.state
are used as follows:
-
When chained methods on isa
and validate
are called (as in isa.integer x
, validate.integer x
),
method
will be set to the name of method to be invoked (here '_isa'
or '_validate'
).
-
As each hedge in a hedgerow is encountered, its name is pushed into the types.state.hedges
list and
its associated test is performed.
-
type testing methods are allowed to set or manipulate the types.state.data
value; this can be used as a
side channel e.g. to cache intermediate and ancillary results from an expensive testing method
-
should an isa
method cause an error with an Intertype
instance with an errors: false
setting,
state.error
will contain that error to enable applications to query for types.state.error?
when an
isa
test has failed. Errors that are thrown instead of being silenced are not recorded in
state.error
.
-
state.data
is a place for the user's type-checking methods to store intermediate data in. It is never
touched by InterType methods except for being reset each time a top-level isa
or validate
is
performed. It can be used to store expensive computational results that are necessitated by
type-checking procedures; for example, one might have a type that is a potentially long list of either
functions or names identifying functions. When checking that the list validates, one has to iterate over
the list and check for all elements being either a function or a name. Knowing that names will have to
be replaced by functions later on, on could have the isa
method cache all those to-be-postprocessed
items:
( x ) ->
@state.data ?= {}
@state.data.name_indexes ?= []
for idx, element in x
switch @type_of element
when 'function'
continue
when 'text'
@state.data.name_indexes.push { idx, element, }
else
return false
...
...
Intertype create
- returns deep copy (structural clone) of
default
member of type declaration - in the case of objects, uses
Object.assign()
to apply optional cfg
- all types can (and maybe should) have a
default
value:
types.create.text()
returns ''
types.create.integer()
and types.create.float()
return 0
types.create.object()
returns {}
types.create.list()
returns []
- and so on
- no implicit type coercion
types.create.quantity()
(for which see below) has default { value: 0, unit: null, }
which does
not satisfy the constraint isa.nonempty.text x.unit
, so causes an error- but
types.create.quantity { unit: 'km', }
works because Object.assign { value: 0, unit: null, }, { unit: 'km', }
gives { value: 0, unit: 'km', }
which does satisfy all constraints of quantity
types.declare.quantity
test: [
( x ) -> @isa.object x
( x ) -> @isa.float x.value
( x ) -> @isa.nonempty.text x.unit
]
default:
value: 0
unit: null
-
create()
is of great help when writing functions with a configuration object (here always called cfg
).
Where in earlier versions of this library one had to write:
f = ( cfg ) ->
types.validate.foobar ( cfg = { defaults.foobar..., cfg..., } )
...
now one can write more succinctly:
f = ( cfg ) ->
cfg = types.create.foobar cfg
...
and have reference to defaults, assignment from structured value and validation all wrapped up inside
one call to a single method.
Intertype equals()
To Do
-
[–] allow to filter out builtin types
-
[–] implement sum types (a.k.a. tagged union, variant, variant record, choice type, discriminated
union, disjoint union, or coproduct :-O) as in isa.integer.or.optional.nonempty.text
-
[–] implement hedges odd
, even
; valid for float
s but do imply those numbers will be integer
-
[–] implement diagnostic API, primarily to check for existence of hedged types; allow to distinguish
between standard types and user-defined types
-
[–] special types:
groups- hedges
- existential / quantified:
anything
: ( x ) -> true
something
: ( x ) -> x?
nothing
: ( x ) -> not x?
-
[–] allow to derive types, including derivation of defaults
-
[–] numeric types:
- [–] rename
number
to real
? to avoid conflict with JS Number
and to clarify that this does not
cover imaginary, complex numbers. Observe we now have BigInt
s pre-generating literally hundreds of
hedgpath chains - [–] consider
float
(includes infinity
) vs ffloat
('finite' float, excludes infinity
)
(longer name, more restricted)
-
[–] salvage
-
[–] implement or
as in types.isa.integer.or.text 'x'
-
[–] consider to turn all hedges into strict owners
-
[–] can we generate random data based on a type declaration (like [Clojure spec
]
does)[https://youtu.be/B_Farscj0hY?t=1562]
-
[–] use sets not arrays when testing for extraneous keys in Type_cfg.constructor()
-
[–] offer a way to collect all errors in validation ('slow fail') instead of bailing out on first
error ('fast fail') (see HN post)
-
[–] make it so that type declarations can be queried / viewed / checked by user, especially
defaults
must be retrievable so they can be referenced from new type declarations offer API
to retrieve, review, print, document type declarations
-
[–] try to find a way to treat hedges, types equally—there shouldn't be any (apparent at least)
difference since in a hedgerow like isa.nonempty.text.or.optional.integer x
the types and hedges proper
both appear all over the place
- [–] in principle then, any combination of hedges proper and types becomes allowable; one could also
say: hedges become types and types are chainable, as in
validate.empty.text x
isnt categorically
different from validate.text.integer x
, even if the latter reads non-sensically and can only ever fail
(because there's no overlap between text values and integer values). Could/should then rule out
non-sensical hedgerows by other means (i.e. a grammar that states what can go where)
-
[–] make the name of the disjunction—by default, 'or'
—configurable
-
[–] allow to configure that optional
shall only applay to null
; additionaly or alternatively,
offer nullable
as a hedge for the same purpose
-
[–] consider to change list_of
, set_of
into list.of
, set.of
, allow for all collections
(text.of
, object.of
, map.of
)
-
[–] implement last_of()
, first_of()
-
[–] try to centralize hedgerow validation; happens in several places now
-
[–] implement aliases
-
[–] implement isa
, validate
, create
as functions that accept hedgerow, value (i.e. can say both
isa.list.of.integer []
and isa 'list', 'of', 'integer', []
, maybe isa.list.of' 'integer', []
, too)
-
[–] currently isa
&c call instance method _isa
&c; make it so that isa
calls super()
and
define effective isa()
in base class Intertype_xxxxx extends Intertype_abc
, Intertype extends Intertype_xxxxx
.
-
[–] re-consider seal
-
[–] implement type dependencies (both explicit and implicit), e.g. codepoint
depends on text
while
codepointid
depends on integer
-
[–] clarify distinction between container
and collection
or remove one of them
-
[–] helpers.dep_copy()
should allow circular objects where necessary
-
[–] structuredClone()
throws an exception when encountering a function (and other things)
-
[–] fix (probably) related bug metteur#1867d3a6535c4d1f12ccc55d359fc6ff681a16e6
Validation Failure
F create mtr_new_template.rpr:optional.function { template: 'the answers are ❰...answer❱.', open: '❰', close: '❱', rpr: null }
F create mtr_new_template Symbol(misfit)
Error: ^intertype/validate@1567^ not a valid boolean (violates 'x is true or false'): Symbol(return_true)
Validation Failure
-
[–] in addition to single-$
-prefixed keys, allow double-$
-prefixed keys to allow arbitrary names
for arbitrary conditions; these should probably always use functions as values:
declare.foobar
$: 'object'
$number: 'optional.float'
$string: 'optional.nonempty.text'
$$either_number_or_string: ( x ) ->
( x.number? or x.string? ) and not ( x.number? and x.string? )
-
[–] implement 'checks', i.e. helpers to test for conditions like 'object has keys that conform to this
pattern' &c (?)
-
[–] turn Type_cfg
instances into functions
-
[–] document that isa.optional.t x
is just a convenient way to write isa.null.or.undefined.or.t x
,
which explains why a hedgerow can be short-circuited as soon as not x?
has been found to be true
-
[–] implement examine
, a non-throwing equivalent to validate
, which returns the test clauses up to
the point of failure or null
. Variant: call it fails
, returns false
where isa
had returned true
,
non-empty list of tests otherwise:
if tests = fails.foobar x # lists are truthy in JS
log tests.at -1 # print info about failed test
-
[–] based on the above, provide nicely formatted error reports so users don't have to
-
[–] implement create
with hedges such that one can write things like
create.nonempty.list.of.integer size: 5
; in this case, the create
method of type integer
should be
called with argument { hedges: [ 'nonempty', 'integer', ], size: 5, }
-
[–] wrap all hedges and type testers to check for arity 1
; mabe this can be done in
_get_hedge_base_proxy_cfg
once for all
-
[–] rule out use of names with cfg.sep
(.
) (generally, check for name being a valid JS identifier;
likewise, sep
should be restricted to non-identifier characters)
-
[–] consider to offer faster mode where all hegerows must get pre-declared instead of being
auto-vivified on-the-fly
-
[–] rename extras
in type descriptions to open
? Or indeed create type noxtra
similar to empty
,
nonempty
: isa.noxtra.foo x
(or isa.foo.noxtra x
?) is true
when isa.foo x
is true
, the
declaration of type foo
enumerates fieldnames, and no fields except these are found in Object.keys x
.
-
[–] allow validate
to take an extra parameter: either string (with placeholders for data?) or
function to be called in case of validation failure; this to make throwing more meaningful errors than
standard validation errors easier probably not possible due to existence of rest parameter in
_validate: ( hedges..., type, x ) ->
; instead, recommend these patterns:
### provide custom value in case of postcondition failure: ###
plus_1 = ( a, b ) ->
R = a + b
return try validate.float.or.bigint R catch error
0
### throw custom error in case of postcondition failure: ###
plus_2 = ( a, b ) ->
R = a + b
return try validate.float.or.bigint R catch error
throw new Error "these values can not be added: a: #{rpr a}, b: #{rpr b}"
-
[–] implement configuration to specifiy whether validation errors should output tracing message and
whether to include tracing in stderr
or print to console or both
-
[–] must use deep copies when deriving values from defaults in create()
-
[–] get_state_report()
may report single line even with format: 'failing'
when test has succeeded,
should return null
-
[–] change default
to defaults
(as in, 'field defaults') to avoid clash with JS reserved word.
Alternative: paragon
template
-
[–] do not use $
-prefixed fieldnames, define fields in fields
sub-object
-
[–] allow list as enumeration of allowed values as in color: [ 'red', 'green', 'blue', ]
-
[–] Implement a demo type quantity
that allows inputs like ms: 42
, km: 3, m: 800
with
normalization
-
[–] make sure key properties of Intertype
instances are hidden to avoid terminal flooding on output
-
[–] implement a way for type tests to communicate a reason for rejection of a value; this should be
picked up by validate
when throwing error
Is Done
-
[+] use
Reflect.has()
to check for property availability in size_of()
reject because Reflect.has()
balks on
primitive values like numbers, too, which further complicates the code instead of making it simpler.
⁂sigh⁂
-
[+] in keeping with APIs for isa[ typename ]
(i.e. isa.integer &c
) and validate[ typename ]
,
implement the same for declare
as in declare.my_type cfg
-
[+] use 'auto-vivification' for hedgepaths as outlined in
hengist/dev/intertype
[–] how to finalize hedges?
[–] demand to declare types with hedgepaths? types.declare.empty.list
? types.declare 'empty', 'list'
?[–] possible to 'auto-vivify' hedgepaths?[–] scrap hedgepaths, replace by isa.$TYPE x, cfg
API? or isa.$TYPE P..., x
where P may be any
number of modifiers as in isa.list 'optional', 'empty', x
-
[+] fix naming of type test functions (always test
, should be name of type)
-
[+] add default
parameter to declare
-
[+] implement create()
-
[+] provide methods for the ubiquitous validate.$TYPE ( cfg = { defaults.$TYPE..., cfg..., } )
as
cfg = types.get_defaults.$TYPE cfg
-
[+] implement
- [+] declarative freezing
[–] declarative sealing- [+] declarative validation of absence of extraneous (enumerable) properties
- [+] declarative object creation with class declaration property
create
(must be function)
-
[+] make hedgepaths configurable—hedges need an opt-in
using depth (length) of hedgepath; default depth is 0using wildcard hedgepath pattern (provided by picomatch
https://github.com/micromatch/picomatch)both at instantiation time for all builtins and declaration time for the type being declared
-
[+] eliminate hedgepaths that end in a hedge instead of in a type (or group). So we don't allow to
test for empty x
, only for empty.collection x
, empty.any x
&c
-
[+] flatten type entries in registry to be simple Type_cfg
instances
-
[+] "a group is a set of types. A group's groups
property is itself, so group collection
is
groupmember of group collection
, meaning there are tests for isa.collection
, isa.empty.collection
and so on."
-
[+] reconsider role of groups in type declarations removed groups altogether, keeping
boolean property collection
-
[+] change collection
to iterable
, b/c their distinguishing mark is that they can be iterated
over by virtue of x[ Symbol.iterator ]
returning a function make collection
a boolean
property of type configuration, implement type iterable
-
[+] implement 'exception-guarding' where we catch exceptions thrown by type testers when so configured
(with errors: false
) and return false
instead, recording the error in state
. When errors: 'throw'
is set, errors will be thrown as normally
-
[+] allow users to access Intertype_user_error
class so they can throw errors that are exempt from
exception-guarding
-
[+] implement using the cfg directly for tests against object (struct) properties. Keys can be
anything but if they start with a $
dollar sign the refer to the keys of the struct being described;
$
refers to the struct itself; string values name an existing type. These additions make
declarations highly declarative and aid in providing automatic features (e.g. implicit type dependency):
declare.quantity
$: 'object' # this could be implicit, judging by the use of any `$`-prefixed key
$value: 'float'
$unit: 'nonempty.text'
default:
value: 0
unit: null