simenge

# Ruby, no bueno
a = 1
def f()
  a=2
end
puts a # => 1

# Ruby, works
a = 1
__sym123 = binding

simenge

Input: 

(begin
    (def (inc-by x) (+ x 1))
    (inc-by 1)
    ('a' | gsub 'a' 'b' | gsub 'b' ('a' | upcase))
    (if (eq? 1 1 (+ 0 (- 2 1))) (puts (+ 1 2 3)))
    (-> (a 1 *b **c d: e: 1 &d) a)
    (-> () (set! inc-by 1))
  )

simenge

module Lisp
  enum Tag
    Str
    Symbol
    Int
    Builtin
    Lambda
    List
    True
    False

simenge

module Test where

data Lisp = Integer Int
          | Str String
          | FloatT Float
          
toString :: Lisp -> String
toString x = case x of
  Integer i -> show i
  | Str s -> s

simenge

module Lisp

  class List
    property list : Array(Lisp::Object)
    def initialize(@list = [] of Lisp::Object)
    end
    def to_s
      "(" + @list.map(&.to_s).join(" ") + ")"
    end
    forward_missing_to list

simenge

simen@DESKTOP-G75FGNT:~$ curl -sSL https://dist.crystal-lang.org/apt/setup.sh | sudo bash
[sudo] password for simen:
Executing: /tmp/apt-key-gpghome.BpBCL6D3uk/gpg.1.sh --keyserver keys.gnupg.net --recv-keys 09617FD37CC06B54
gpg: connecting dirmngr at '/tmp/apt-key-gpghome.BpBCL6D3uk/S.dirmngr' failed: IPC connect call failed
gpg: keyserver receive failed: No dirmngr
Get:1 http://archive.ubuntu.com/ubuntu bionic InRelease [242 kB]
Get:2 http://security.ubuntu.com/ubuntu bionic-security InRelease [83.2 kB]
Get:3 http://archive.ubuntu.com/ubuntu bionic-updates InRelease [88.7 kB]
Get:4 http://archive.ubuntu.com/ubuntu bionic-backports InRelease [74.6 kB]
Get:5 https://dist.crystal-lang.org/apt crystal InRelease [2478 B]

simenge

module Pat
  macro match(&block)
    case {{block.body.cond}}
    {% for whens in block.body.whens %}
      {% if whens.conds.first.is_a?(Cast) %}
        when {{whens.conds.first.to}}
          {{whens.conds.first.obj}} = {{block.body.cond}}
          {{whens.body}}
      {% elsif whens.conds.first.is_a?(ArrayLiteral) %}
        when {{block.body.cond}}.is_a?(Array) && {{block.body.cond}}.as(Array).size == {{whens.conds.first.size}}

simenge

match {
  case sexpr
  when [sym("def"), params.as(Array(LispSymbol), rest(body.as(Array(LispObject))))]
    # params is now bound to an Array(LispSymbol) and body to an array of LispObject
    # consisting of sexpr[2..-1]
  end
}

simenge

def annotate_tc(s : LispObject)
  # Automatically annotating tail calls can be tricky, because we need to
  # properly recurse while terminating at the right points. In particular:
  #   * The last expr in a function body is in tail position (TP)
  #   * If a function call is in TP, we need to annotate it
  #   * If an if expr is in TP, we need to annotate each branch
  #   * If a fn literal is in TP, we need to recursively call annotate_tc.
  #     However, we will not do this from within annotate_tc; rather,
  #     Interpreter#eval_fn, which evaluates a function literal and
  #     returns a Lisp::Lambda object, will call