basedOn.nim
A library for cleanly creating an object or tuple based on another object or tuple.
It has simple syntax and compiles directly to a block wherein a variable is mutated
according to the body of the statement.
This project is licensed under the MIT License.
Installation
Install with nimble.
$ nimble install basedOnUsage
basedOn(base):
member1 = expression
# ...
memberN = expressionUsage Example
Let us say we have a class...
type Foo = object
bar: int
foobar: string...and a base object.
const myFoo = Foo(bar: 1, foobar: "Hello")We can make a new object based on MyFoo:
import basedOn
const myNewFoo = basedOn(myFoo):
bar = myFoo.bar * 10 + 20
foobar = myFoo.foobar & " world!"
# is the essentially the same as:
#
# const myNewFoo = Foo(
# bar: myFoo.bar * 10 + 20,
# foobar: myFoo.foobar & " world!"
# )
assert myNewFoo.bar == 1 * 10 + 20
assert myNewFoo.foobar == "Hello" & " world!"const myNewFoo2 = basedOn(myFoo):
bar = 30
# We don't even have to change all of the object's members!
# is the essentially the same as:
#
# const myNewFoo2 = Foo(
# bar: 30,
# foobar: myFoo.foobar
# )
assert myNewFoo2.bar == 30
assert myNewFoo2.foobar == "Hello"Compilation Example
The previous code...
const myNewFoo = basedOn(myFoo):
bar = myFoo.bar * 10 + 20
foobar = myFoo.foobar & " world!"is exactly the same as:
const myNewFoo = block:
var result = myFoo
result.bar = myFoo.bar * 10 + 20
result.foobar = myFoo.foobar & " world!"
result
