095b73ea |
1 | #! /usr/bin/env crystal run |
2 | |
3 | require "./readline" |
4 | require "./reader" |
5 | require "./printer" |
6 | require "./types" |
7 | require "./env" |
b31653d5 |
8 | require "./core" |
2c76c2ff |
9 | require "./error" |
095b73ea |
10 | |
11 | # Note: |
12 | # Employed downcase names because Crystal prohibits uppercase names for methods |
13 | |
7fe6282e |
14 | def func_of(env, binds, body) |
095b73ea |
15 | -> (args : Array(Mal::Type)) { |
16 | new_env = Mal::Env.new(env, binds, args) |
7fe6282e |
17 | eval(body, new_env) |
095b73ea |
18 | } as Mal::Func |
19 | end |
20 | |
095b73ea |
21 | def eval_ast(ast, env) |
2c76c2ff |
22 | return ast.map{|n| eval(n, env) as Mal::Type} if ast.is_a? Mal::List |
7fe6282e |
23 | |
2c76c2ff |
24 | val = ast.unwrap |
7fe6282e |
25 | |
26 | Mal::Type.new case val |
095b73ea |
27 | when Mal::Symbol |
2c76c2ff |
28 | if e = env.get(val.str) |
095b73ea |
29 | e |
30 | else |
2c76c2ff |
31 | eval_error "'#{val.str}' not found" |
095b73ea |
32 | end |
33 | when Mal::List |
7fe6282e |
34 | val.each_with_object(Mal::List.new){|n, l| l << eval(n, env)} |
095b73ea |
35 | when Mal::Vector |
7fe6282e |
36 | val.each_with_object(Mal::Vector.new){|n, l| l << eval(n, env)} |
095b73ea |
37 | when Mal::HashMap |
7fe6282e |
38 | val.each{|k, v| val[k] = eval(v, env)} |
39 | val |
095b73ea |
40 | else |
7fe6282e |
41 | val |
095b73ea |
42 | end |
43 | end |
44 | |
45 | def read(str) |
46 | read_str str |
47 | end |
48 | |
49 | def eval(ast, env) |
2c76c2ff |
50 | list = ast.unwrap |
7fe6282e |
51 | |
2c76c2ff |
52 | return eval_ast(ast, env) unless list.is_a? Mal::List |
53 | return Mal::Type.new Mal::List.new if list.empty? |
095b73ea |
54 | |
2c76c2ff |
55 | head = list.first.unwrap |
095b73ea |
56 | |
7fe6282e |
57 | Mal::Type.new case head |
bed63064 |
58 | when Mal::Symbol |
9b8a3da9 |
59 | case head.str |
bed63064 |
60 | when "def!" |
7fe6282e |
61 | eval_error "wrong number of argument for 'def!'" unless list.size == 3 |
2c76c2ff |
62 | a1 = list[1].unwrap |
63 | eval_error "1st argument of 'def!' must be symbol" unless a1.is_a? Mal::Symbol |
64 | env.set(a1.str, eval(list[2], env)) |
bed63064 |
65 | when "let*" |
7fe6282e |
66 | eval_error "wrong number of argument for 'def!'" unless list.size == 3 |
bed63064 |
67 | |
9b8a3da9 |
68 | bindings = list[1].unwrap |
2c76c2ff |
69 | eval_error "1st argument of 'let*' must be list or vector" unless bindings.is_a? Array |
bed63064 |
70 | eval_error "size of binding list must be even" unless bindings.size.even? |
71 | |
72 | new_env = Mal::Env.new env |
73 | bindings.each_slice(2) do |binding| |
9b8a3da9 |
74 | key, value = binding |
75 | name = key.unwrap |
2c76c2ff |
76 | eval_error "name of binding must be specified as symbol" unless name.is_a? Mal::Symbol |
77 | new_env.set(name.str, eval(value, new_env)) |
bed63064 |
78 | end |
79 | |
7fe6282e |
80 | eval(list[2], new_env) |
bed63064 |
81 | when "do" |
7fe6282e |
82 | list.shift(1) |
83 | eval_ast(list, env).last |
bed63064 |
84 | when "if" |
7fe6282e |
85 | cond = eval(list[1], env) |
bed63064 |
86 | case cond |
87 | when Nil |
7fe6282e |
88 | list.size >= 4 ? eval(list[3], env) : nil |
bed63064 |
89 | when false |
7fe6282e |
90 | list.size >= 4 ? eval(list[3], env) : nil |
bed63064 |
91 | else |
7fe6282e |
92 | eval(list[2], env) |
bed63064 |
93 | end |
94 | when "fn*" |
95 | # Note: |
7fe6282e |
96 | # If writing lambda expression here directly, compiler will fail to infer type of 'list'. (Error 'Nil for empty?') |
9b8a3da9 |
97 | func_of(env, list[1].unwrap, list[2]) |
095b73ea |
98 | else |
2c76c2ff |
99 | f = eval_ast(list.first, env).unwrap |
100 | eval_error "expected function symbol as the first symbol of list" unless f.is_a? Mal::Func |
7fe6282e |
101 | list.shift(1) |
102 | f.call eval_ast(list, env) |
095b73ea |
103 | end |
095b73ea |
104 | else |
2c76c2ff |
105 | f = eval(list.first, env).unwrap |
106 | eval_error "expected function symbol as the first symbol of list" unless f.is_a? Mal::Func |
7fe6282e |
107 | list.shift(1) |
108 | f.call eval_ast(list, env) |
095b73ea |
109 | end |
110 | end |
111 | |
112 | def print(result) |
113 | pr_str(result, true) |
114 | end |
115 | |
116 | def rep(str) |
117 | print(eval(read(str), $repl_env)) |
118 | end |
119 | |
b31653d5 |
120 | $repl_env = Mal::Env.new nil |
7fe6282e |
121 | Mal::NS.each{|k,v| $repl_env.set(k, Mal::Type.new(v))} |
b31653d5 |
122 | |
095b73ea |
123 | while line = my_readline("user> ") |
124 | begin |
125 | puts rep(line) |
126 | rescue e |
127 | STDERR.puts e |
128 | end |
129 | end |