[ruby-core:98195] [Ruby master Feature#16746] Endless method definition

Issue #16746 has been updated by Eregon (Benoit Daloze).


Is it intended to allow multi-line definitions in this style?
I think we should not, and only single-line expressions should be allowed.

I think that's not the original purpose of this ticket and rather an incorrect usage of this new syntax,
e.g., https://twitter.com/devoncestes/status/1256222228431228933

----------------------------------------
Feature #16746: Endless method definition
https://bugs.ruby-lang.org/issues/16746#change-85433

* Author: mame (Yusuke Endoh)
* Status: Closed
* Priority: Normal
* Assignee: nobu (Nobuyoshi Nakada)
----------------------------------------
Ruby syntax is full of "end"s.  I'm paranoid that the ends end Ruby.  I hope Ruby is endless.

So, I'd like to propose a new method definition syntax.

```ruby
def: value(args) = expression
```

As you see, there is no "end".

Examples.

```ruby
def: hello(name) =
  puts("Hello, #{ name }")

hello("endless Ruby") #=> Hello, endless Ruby
```

```ruby
def: inc(x) = x + 1

p inc(42) #=> 43
```

```ruby
x = Object.new

def: x.foo = "FOO"

p x.foo #=> "FOO"
```

```ruby
def: fib(x) =
  x < 2 ? x : fib(x-1) + fib(x-2)

p fib(10) #=> 55
```

Limitations.

* `def: foo x = x` is invalid; the parentheses for formal arguments are mandatory.
* `private def: foo = x` is invalid; this method definition cannot be an method argument.

A patch is attached.  No conflicts.

---Files--------------------------------
endless-method-definition.patch (2.47 KB)


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