1 #! /usr/bin/env crystal run
12 # Employed downcase names because Crystal prohibits uppercase names for methods
17 def func_of(env, binds, body)
18 ->(args : Array(Mal::Type)) {
19 new_env = Mal::Env.new(env, binds, args)
24 def eval_ast(ast, env)
25 return ast.map { |n| eval(n, env).as(Mal::Type) } if ast.is_a? Mal::List
29 Mal::Type.new case val
31 if e = env.get(val.str)
34 eval_error "'#{val.str}' not found"
37 val.each_with_object(Mal::List.new) { |n, l| l << eval(n, env) }
39 val.each_with_object(Mal::Vector.new) { |n, l| l << eval(n, env) }
41 val.map { |n| eval(n, env).as(Mal::Type) }
43 val.each { |k, v| val[k] = eval(v, env) }
55 {{list}}.is_a?(Array) && !{{list}}.empty?
63 Mal::List.new << gen_type(Mal::Symbol, "quote") << ast
67 head = list.first.unwrap
71 when head.is_a?(Mal::Symbol) && head.str == "unquote"
73 # (("splice-unquote" ...) ...)
74 when pair?(head) && (arg0 = head.first.unwrap).is_a?(Mal::Symbol) && arg0.str == "splice-unquote"
75 tail = Mal::Type.new list[1..-1].to_mal
77 Mal::List.new << gen_type(Mal::Symbol, "concat") << head[1] << quasiquote(tail)
80 tail = Mal::Type.new list[1..-1].to_mal
82 Mal::List.new << gen_type(Mal::Symbol, "cons") << quasiquote(list.first) << quasiquote(tail)
87 def macro_call?(ast, env)
89 return false unless list.is_a? Mal::List
90 return false if list.empty?
92 sym = list.first.unwrap
93 return false unless sym.is_a? Mal::Symbol
95 func = env.find(sym.str).try(&.data[sym.str])
96 return false unless func && func.macro?
101 def macroexpand(ast, env)
102 while macro_call?(ast, env)
103 # Already checked in macro_call?
104 list = ast.unwrap.as(Mal::List)
105 func_sym = list[0].unwrap.as(Mal::Symbol)
106 func = env.get(func_sym.str).unwrap
110 ast = func.call(list[1..-1])
112 ast = func.fn.call(list[1..-1])
114 eval_error "macro '#{func_sym.str}' must be function: #{ast}"
121 macro invoke_list(l, env)
122 f = eval({{l}}.first, {{env}}).unwrap
123 args = eval_ast({{l}}[1..-1].to_mal, {{env}})
127 {{env}} = Mal::Env.new(f.env, f.params, args)
132 eval_error "expected function as the first argument: #{f}"
137 # 'next' in 'do...end' has a bug in crystal 0.7.1
138 # https://github.com/manastech/crystal/issues/659
142 return eval_ast(ast, env) unless list.is_a? Mal::List
143 return ast if list.empty?
145 ast = macroexpand(ast, env)
149 return eval_ast(ast, env) unless list.is_a? Mal::List
150 return ast if list.empty?
152 head = list.first.unwrap
154 return invoke_list(list, env) unless head.is_a? Mal::Symbol
156 return Mal::Type.new case head.str
158 eval_error "wrong number of argument for 'def!'" unless list.size == 3
160 eval_error "1st argument of 'def!' must be symbol: #{a1}" unless a1.is_a? Mal::Symbol
161 env.set(a1.str, eval(list[2], env))
163 eval_error "wrong number of argument for 'def!'" unless list.size == 3
165 bindings = list[1].unwrap
166 eval_error "1st argument of 'let*' must be list or vector" unless bindings.is_a? Array
167 eval_error "size of binding list must be even" unless bindings.size.even?
169 new_env = Mal::Env.new env
170 bindings.each_slice(2) do |binding|
173 eval_error "name of binding must be specified as symbol #{name}" unless name.is_a? Mal::Symbol
174 new_env.set(name.str, eval(value, new_env))
177 ast, env = list[2], new_env
181 ast = Mal::Type.new nil
185 eval_ast(list[1..-2].to_mal, env)
189 ast = unless eval(list[1], env).unwrap
190 list.size >= 4 ? list[3] : Mal::Type.new(nil)
196 params = list[1].unwrap
197 unless params.is_a? Array
198 eval_error "'fn*' parameters must be list or vector: #{params}"
200 Mal::Closure.new(list[2], params, env, func_of(env, params, list[2]))
204 ast = quasiquote list[1]
207 eval_error "wrong number of argument for 'defmacro!'" unless list.size == 3
209 eval_error "1st argument of 'defmacro!' must be symbol: #{a1}" unless a1.is_a? Mal::Symbol
210 env.set(a1.str, eval(list[2], env).tap { |n| n.is_macro = true })
212 macroexpand(list[1], env)
214 catch_list = list.size >= 3 ? list[2].unwrap : Mal::Type.new(nil)
215 return eval(list[1], env) unless catch_list.is_a? Mal::List
217 catch_head = catch_list.first.unwrap
218 return eval(list[1], env) unless catch_head.is_a? Mal::Symbol
219 return eval(list[1], env) unless catch_head.str == "catch*"
223 rescue e : Mal::RuntimeException
224 new_env = Mal::Env.new(env, [catch_list[1]], [e.thrown])
225 eval(catch_list[2], new_env)
227 new_env = Mal::Env.new(env, [catch_list[1]], [Mal::Type.new e.message])
228 eval(catch_list[2], new_env)
231 invoke_list(list, env)
241 print(eval(read(str), REPL_ENV))
245 REPL_ENV = Mal::Env.new nil
246 Mal::NS.each { |k, v| REPL_ENV.set(k, Mal::Type.new(v)) }
247 REPL_ENV.set("eval", Mal::Type.new ->(args : Array(Mal::Type)) { Mal.eval(args[0], REPL_ENV) })
248 Mal.rep "(def! not (fn* (a) (if a false true)))"
249 Mal.rep "(def! load-file (fn* (f) (eval (read-string (str \"(do \" (slurp f) \")\")))))"
250 Mal.rep "(defmacro! cond (fn* (& xs) (if (> (count xs) 0) (list 'if (first xs) (if (> (count xs) 1) (nth xs 1) (throw \"odd number of forms to cond\")) (cons 'cond (rest (rest xs)))))))"
253 REPL_ENV.set("*ARGV*", Mal::Type.new argv)
257 ARGV[1..-1].each do |a|
258 argv << Mal::Type.new(a)
263 Mal.rep "(load-file \"#{ARGV[0]}\")"
270 while line = Readline.readline("user> ", true)
273 rescue e : Mal::RuntimeException
274 STDERR.puts "Error: #{pr_str(e.thrown, true)}"
276 STDERR.puts "Error: #{e}"