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|
-----
--- Type definitions (`type.Type` and implementations).
--
-- @module type
import opairs from require 'alv.util'
import result from require 'alv.cycle'
import Error from require 'alv.error'
shared_shape = (a, b) ->
for key in pairs a
return false unless b[key]
for key in pairs b
return false unless a[key]
true
same = (a, b) ->
return unless shared_shape a, b
for key, val in pairs a
return false unless val == b[key]
true
local Primitive
--- Magic table containing all `Primitive` types.
--
-- When indexed with a string returns a (cached) instance of that type.
--
-- @table T
T = setmetatable {}, __index: (key) =>
with type = Primitive key
rawset @, key, type
--- Base class for types.
-- @type Type
class Type
--- pretty-print a value of this type.
-- @function pp
-- @tparam any value
-- @treturn string
--- check two values of this type for equality.
-- @function eq
-- @tparam any a
-- @tparam any b
-- @treturn bool
--- index into this type or throw a error.
-- @function get
-- @tparam any key
-- @treturn Type
--- create a `SigStream` of this type.
-- @tparam ?any init initial value
-- @treturn SigStream
mk_sig: (init) =>
result.SigStream @, init
--- create a `EvtStream` of this type.
-- @treturn EvtStream
mk_evt: =>
result.EvtStream @
--- create a `Constant` of this type.
-- @tparam any val value
-- @treturn Constant
mk_const: (val) =>
result.Constant @, val
--- Primitive type.
--
-- Extends `Type`.
--
-- @type Primitive
class Primitive extends Type
pp: (value) =>
switch @name
when 'str'
string.format '%q', value
else
tostring value
eq: (a, b) => a == b
get: (key) => error "cannot index into Primitive type '#{@}'"
__eq: (other) => @name == other.name
__tostring: => @name
--- instantiate a Primitive type.
-- @classmethod
-- @tparam string name the typename
new: (@name) =>
assert (type @name) == 'string', "Typename has to be a string: '#{@name}'"
--- the type's unique name.
-- @tfield string name
--- Struct/Hashmap type.
--
-- Extends `Type`.
--
-- @type Struct
class Struct extends Type
pp: (value) =>
inner = table.concat ["#{k}: #{@types[k]\pp v}" for k, v in opairs value], ' '
"{#{inner}}"
eq: (a, b) =>
return false unless (type a) == (type b)
return true if a == b
for key, type in pairs @types
if not type\eq a[key], b[key]
return false
true
get: (key) =>
assert @types[key], Error 'index', "#{@} has no '#{key}' key"
--- iterate over contained keys and types
-- each iteration, returns a key and associated type
-- @treturn string key
-- @treturn Type associated type
iter_keys: => next, @types, nil
--- create a new struct type with a subset of keys.
project: (keys) =>
types = {}
for key in *keys
types[key] = @types[key]
@@ types
__eq: (other) => other.__class == Struct and same @types, other.types
__tostring: =>
inner = table.concat ["#{k}: #{v}" for k, v in opairs @types], ' '
"{#{inner}}"
--- instantiate a Primitive type.
-- @classmethod
-- @tparam {string=Type} types
new: (@types) =>
--- the shape and field types of the struct.
-- @tfield {string=Type} types
--- Array type.
--
-- Extends `Type`.
--
-- @type Array
class Array extends Type
pp: (value) =>
inner = table.concat [@type\pp v for v in *value], ' '
"[#{inner}]"
eq: (a, b) =>
return false unless (type a) == (type b)
for i=1, @size
if not @type\eq a[i], b[i]
return false
true
get: (key) =>
assert (type key) == 'number'
assert key >= 0 and key < @size, Error 'index', "index '#{key}' out of range!"
@type
array_next = (i) => if i < @size then i + 1, @type
--- iterate over contained types
-- each iteration, returns a key and associated type
-- @treturn number key
-- @treturn Type associated type
iter_keys: => array_next, @, 0
__eq: (other) => other.__class == Array and @size == other.size and @type == other.type
__tostring: => "#{@type}[#{@size}]"
--- instantiate an Array type.
-- @classmethod
-- @tparam number size
-- @tparam Type type
new: (@size, @type) =>
--- the number of elements in this array.
-- @tfield number size
--- the element type of this array.
-- @tfield Type type
{
:Type
:T
:Primitive
:Array
:Struct
}
|
