| 1 | #! /usr/bin/env crystal run |
| 2 | |
| 3 | require "./readline" |
| 4 | require "./reader" |
| 5 | require "./printer" |
| 6 | require "./types" |
| 7 | require "./env" |
| 8 | |
| 9 | # Note: |
| 10 | # Employed downcase names because Crystal prohibits uppercase names for methods |
| 11 | |
| 12 | def eval_error(msg) |
| 13 | raise Mal::EvalException.new msg |
| 14 | end |
| 15 | |
| 16 | def num_func(func) |
| 17 | -> (args : Array(Mal::Type)) { |
| 18 | x, y = args[0].unwrap, args[1].unwrap |
| 19 | eval_error "invalid arguments" unless x.is_a?(Int64) && y.is_a?(Int64) |
| 20 | Mal::Type.new func.call(x, y) |
| 21 | } |
| 22 | end |
| 23 | |
| 24 | $repl_env = Mal::Env.new nil |
| 25 | $repl_env.set("+", Mal::Type.new num_func(->(x : Int64, y : Int64){ x + y })) |
| 26 | $repl_env.set("-", Mal::Type.new num_func(->(x : Int64, y : Int64){ x - y })) |
| 27 | $repl_env.set("*", Mal::Type.new num_func(->(x : Int64, y : Int64){ x * y })) |
| 28 | $repl_env.set("/", Mal::Type.new num_func(->(x : Int64, y : Int64){ x / y })) |
| 29 | |
| 30 | module Mal |
| 31 | extend self |
| 32 | |
| 33 | def eval_ast(a, env) |
| 34 | return a.map{|n| eval(n, env) } if a.is_a? Array |
| 35 | |
| 36 | Mal::Type.new case ast = a.unwrap |
| 37 | when Mal::Symbol |
| 38 | if e = env.get(ast.str) |
| 39 | e |
| 40 | else |
| 41 | eval_error "'#{ast.str}' not found" |
| 42 | end |
| 43 | when Mal::List |
| 44 | ast.each_with_object(Mal::List.new){|n, l| l << eval(n, env)} |
| 45 | when Mal::Vector |
| 46 | ast.each_with_object(Mal::Vector.new){|n, l| l << eval(n, env)} |
| 47 | when Mal::HashMap |
| 48 | new_map = Mal::HashMap.new |
| 49 | ast.each{|k, v| new_map[k] = eval(v, env)} |
| 50 | new_map |
| 51 | else |
| 52 | ast |
| 53 | end |
| 54 | end |
| 55 | |
| 56 | def read(str) |
| 57 | read_str str |
| 58 | end |
| 59 | |
| 60 | def eval(t, env) |
| 61 | ast = t.unwrap |
| 62 | |
| 63 | return eval_ast(t, env) unless ast.is_a?(Mal::List) |
| 64 | return gen_type Mal::List if ast.empty? |
| 65 | |
| 66 | sym = ast.first.unwrap |
| 67 | eval_error "first element of list must be a symbol" unless sym.is_a?(Mal::Symbol) |
| 68 | |
| 69 | Mal::Type.new case sym.str |
| 70 | when "def!" |
| 71 | eval_error "wrong number of argument for 'def!'" unless ast.size == 3 |
| 72 | a1 = ast[1].unwrap |
| 73 | eval_error "1st argument of 'def!' must be symbol" unless a1.is_a?(Mal::Symbol) |
| 74 | env.set(a1.str, eval(ast[2], env) as Mal::Type) |
| 75 | when "let*" |
| 76 | eval_error "wrong number of argument for 'def!'" unless ast.size == 3 |
| 77 | |
| 78 | bindings = ast[1].unwrap |
| 79 | eval_error "1st argument of 'let*' must be list or vector" unless bindings.is_a?(Array) |
| 80 | eval_error "size of binding list must be even" unless bindings.size.even? |
| 81 | |
| 82 | new_env = Mal::Env.new env |
| 83 | bindings.each_slice(2) do |binding| |
| 84 | name, value = binding[0].unwrap, binding[1] |
| 85 | eval_error "name of binding must be specified as symbol" unless name.is_a?(Mal::Symbol) |
| 86 | new_env.set(name.str, eval(value, new_env)) |
| 87 | end |
| 88 | |
| 89 | eval(ast[2], new_env) |
| 90 | else |
| 91 | f = eval_ast(ast.first, env) |
| 92 | ast.shift(1) |
| 93 | args = eval_ast(ast, env) |
| 94 | |
| 95 | if f.is_a?(Mal::Type) && (f2 = f.unwrap).is_a?(Mal::Func) |
| 96 | f2.call(args as Array(Mal::Type)) |
| 97 | else |
| 98 | eval_error "expected function symbol as the first symbol of list" |
| 99 | end |
| 100 | end |
| 101 | end |
| 102 | |
| 103 | def print(result) |
| 104 | pr_str(result, true) |
| 105 | end |
| 106 | |
| 107 | def rep(str) |
| 108 | print(eval(read(str), $repl_env)) |
| 109 | end |
| 110 | end |
| 111 | |
| 112 | while line = my_readline("user> ") |
| 113 | begin |
| 114 | puts Mal.rep(line) |
| 115 | rescue e |
| 116 | STDERR.puts e |
| 117 | end |
| 118 | end |