You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
115 lines
2.9 KiB
115 lines
2.9 KiB
#! /usr/bin/env crystal run
|
|
|
|
require "./readline"
|
|
require "./reader"
|
|
require "./printer"
|
|
require "./types"
|
|
require "./env"
|
|
|
|
# Note:
|
|
# Employed downcase names because Crystal prohibits uppercase names for methods
|
|
|
|
def eval_error(msg)
|
|
raise Mal::EvalException.new msg
|
|
end
|
|
|
|
def num_func(func)
|
|
-> (args : Array(Mal::Type)) {
|
|
x, y = args[0].unwrap, args[1].unwrap
|
|
eval_error "invalid arguments" unless x.is_a?(Int32) && y.is_a?(Int32)
|
|
Mal::Type.new func.call(x, y)
|
|
}
|
|
end
|
|
|
|
$repl_env = Mal::Env.new nil
|
|
$repl_env.set("+", Mal::Type.new num_func(->(x : Int32, y : Int32){ x + y }))
|
|
$repl_env.set("-", Mal::Type.new num_func(->(x : Int32, y : Int32){ x - y }))
|
|
$repl_env.set("*", Mal::Type.new num_func(->(x : Int32, y : Int32){ x * y }))
|
|
$repl_env.set("/", Mal::Type.new num_func(->(x : Int32, y : Int32){ x / y }))
|
|
|
|
def eval_ast(a, env)
|
|
return a.map{|n| eval(n, env) } if a.is_a? Array
|
|
|
|
Mal::Type.new case ast = a.unwrap
|
|
when Mal::Symbol
|
|
if e = env.get(ast.str)
|
|
e
|
|
else
|
|
eval_error "'#{ast.str}' not found"
|
|
end
|
|
when Mal::List
|
|
ast.each_with_object(Mal::List.new){|n, l| l << eval(n, env)}
|
|
when Mal::Vector
|
|
ast.each_with_object(Mal::Vector.new){|n, l| l << eval(n, env)}
|
|
when Mal::HashMap
|
|
new_map = Mal::HashMap.new
|
|
ast.each{|k, v| new_map[k] = eval(v, env)}
|
|
new_map
|
|
else
|
|
ast
|
|
end
|
|
end
|
|
|
|
def read(str)
|
|
read_str str
|
|
end
|
|
|
|
def eval(t, env)
|
|
ast = t.unwrap
|
|
|
|
return eval_ast(t, env) unless ast.is_a?(Mal::List)
|
|
|
|
eval_error "empty list" if ast.empty?
|
|
|
|
sym = ast.first.unwrap
|
|
eval_error "first element of list must be a symbol" unless sym.is_a?(Mal::Symbol)
|
|
|
|
Mal::Type.new case sym.str
|
|
when "def!"
|
|
eval_error "wrong number of argument for 'def!'" unless ast.size == 3
|
|
a1 = ast[1].unwrap
|
|
eval_error "1st argument of 'def!' must be symbol" unless a1.is_a?(Mal::Symbol)
|
|
env.set(a1.str, eval(ast[2], env) as Mal::Type)
|
|
when "let*"
|
|
eval_error "wrong number of argument for 'def!'" unless ast.size == 3
|
|
|
|
bindings = ast[1].unwrap
|
|
eval_error "1st argument of 'let*' must be list or vector" unless bindings.is_a?(Array)
|
|
eval_error "size of binding list must be even" unless bindings.size.even?
|
|
|
|
new_env = Mal::Env.new env
|
|
bindings.each_slice(2) do |binding|
|
|
name, value = binding[0].unwrap, binding[1]
|
|
eval_error "name of binding must be specified as symbol" unless name.is_a?(Mal::Symbol)
|
|
new_env.set(name.str, eval(value, new_env))
|
|
end
|
|
|
|
eval(ast[2], new_env)
|
|
else
|
|
f = eval_ast(ast.first, env)
|
|
ast.shift(1)
|
|
args = eval_ast(ast, env)
|
|
|
|
if f.is_a?(Mal::Type) && (f2 = f.unwrap).is_a?(Mal::Func)
|
|
f2.call(args as Array(Mal::Type))
|
|
else
|
|
eval_error "expected function symbol as the first symbol of list"
|
|
end
|
|
end
|
|
end
|
|
|
|
def print(result)
|
|
pr_str(result, true)
|
|
end
|
|
|
|
def rep(str)
|
|
print(eval(read(str), $repl_env))
|
|
end
|
|
|
|
while line = my_readline("user> ")
|
|
begin
|
|
puts rep(line)
|
|
rescue e
|
|
STDERR.puts e
|
|
end
|
|
end
|