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1 | #! /usr/bin/env crystal run |
2 | |
3 | require "./readline" |
4 | require "./reader" |
5 | require "./printer" |
6 | require "./types" |
7 | require "./env" |
8 | require "./core" |
9 | require "./error" |
10 | |
11 | # Note: |
12 | # Employed downcase names because Crystal prohibits uppercase names for methods |
13 | |
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14 | module Mal |
15 | extend self |
16 | |
17 | def func_of(env, binds, body) |
18 | -> (args : Array(Mal::Type)) { |
19 | new_env = Mal::Env.new(env, binds, args) |
20 | eval(body, new_env) |
21 | } as Mal::Func |
22 | end |
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23 | |
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24 | def eval_ast(ast, env) |
25 | return ast.map{|n| eval(n, env) as Mal::Type} if ast.is_a? Mal::List |
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26 | |
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27 | val = ast.unwrap |
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28 | |
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29 | Mal::Type.new case val |
30 | when Mal::Symbol |
31 | if e = env.get(val.str) |
32 | e |
33 | else |
34 | eval_error "'#{val.str}' not found" |
35 | end |
36 | when Mal::List |
37 | val.each_with_object(Mal::List.new){|n, l| l << eval(n, env)} |
38 | when Mal::Vector |
39 | val.each_with_object(Mal::Vector.new){|n, l| l << eval(n, env)} |
40 | when Array(Mal::Type) |
41 | val.map{|n| eval(n, env)} |
42 | when Mal::HashMap |
43 | val.each{|k, v| val[k] = eval(v, env)} |
44 | val |
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45 | else |
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46 | val |
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47 | end |
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48 | end |
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49 | |
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50 | def read(str) |
51 | read_str str |
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52 | end |
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53 | |
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54 | macro is_pair(list) |
55 | {{list}}.is_a?(Array) && !{{list}}.empty? |
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56 | end |
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57 | |
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58 | def quasiquote(ast) |
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59 | list = ast.unwrap |
60 | |
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61 | unless is_pair(list) |
62 | return Mal::Type.new( |
63 | Mal::List.new << gen_type(Mal::Symbol, "quote") << ast |
64 | ) |
65 | end |
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66 | |
67 | head = list.first.unwrap |
68 | |
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69 | case |
70 | # ("unquote" ...) |
71 | when head.is_a?(Mal::Symbol) && head.str == "unquote" |
72 | list[1] |
73 | # (("splice-unquote" ...) ...) |
74 | when is_pair(head) && (arg0 = head.first.unwrap).is_a?(Mal::Symbol) && arg0.str == "splice-unquote" |
75 | tail = Mal::Type.new list[1..-1].each_with_object(Mal::List.new){|e,l| l << e} |
76 | Mal::Type.new( |
77 | Mal::List.new << gen_type(Mal::Symbol, "concat") << head[1] << quasiquote(tail) |
78 | ) |
79 | else |
80 | tail = Mal::Type.new list[1..-1].each_with_object(Mal::List.new){|e,l| l << e} |
81 | Mal::Type.new( |
82 | Mal::List.new << gen_type(Mal::Symbol, "cons") << quasiquote(list.first) << quasiquote(tail) |
83 | ) |
84 | end |
85 | end |
86 | |
87 | macro invoke_list(l, env) |
88 | f = eval({{l}}.first, {{env}}).unwrap |
89 | args = eval_ast({{l}}[1..-1].each_with_object(Mal::List.new){|i, l| l << i}, {{env}}) |
90 | case f |
91 | when Mal::Closure |
92 | ast = f.ast |
93 | {{env}} = Mal::Env.new(f.env, f.params, args) |
94 | next # TCO |
95 | when Mal::Func |
96 | return f.call args |
97 | else |
98 | eval_error "expected function as the first argument" |
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99 | end |
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100 | end |
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101 | |
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102 | def eval(ast, env) |
103 | # 'next' in 'do...end' has a bug in crystal 0.7.1 |
104 | # https://github.com/manastech/crystal/issues/659 |
105 | while true |
106 | list = ast.unwrap |
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107 | |
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108 | return eval_ast(ast, env) unless list.is_a? Mal::List |
109 | return gen_type Mal::List if list.empty? |
110 | |
111 | head = list.first.unwrap |
112 | |
113 | unless head.is_a? Mal::Symbol |
114 | return invoke_list(list, env) |
115 | end |
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116 | |
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117 | return Mal::Type.new case head.str |
118 | when "def!" |
119 | eval_error "wrong number of argument for 'def!'" unless list.size == 3 |
120 | a1 = list[1].unwrap |
121 | eval_error "1st argument of 'def!' must be symbol" unless a1.is_a? Mal::Symbol |
122 | env.set(a1.str, eval(list[2], env)) |
123 | when "let*" |
124 | eval_error "wrong number of argument for 'def!'" unless list.size == 3 |
125 | |
126 | bindings = list[1].unwrap |
127 | eval_error "1st argument of 'let*' must be list or vector" unless bindings.is_a? Array |
128 | eval_error "size of binding list must be even" unless bindings.size.even? |
129 | |
130 | new_env = Mal::Env.new env |
131 | bindings.each_slice(2) do |binding| |
132 | key, value = binding |
133 | name = key.unwrap |
134 | eval_error "name of binding must be specified as symbol" unless name.is_a? Mal::Symbol |
135 | new_env.set(name.str, eval(value, new_env)) |
136 | end |
137 | |
138 | ast, env = list[2], new_env |
139 | next # TCO |
140 | when "do" |
141 | if list.empty? |
142 | ast = Mal::Type.new nil |
143 | next |
144 | end |
145 | |
146 | eval_ast(list[1..-2].each_with_object(Mal::List.new){|i,l| l << i}, env) |
147 | ast = list.last |
148 | next # TCO |
149 | when "if" |
150 | ast = unless eval(list[1], env).unwrap |
151 | list.size >= 4 ? list[3] : Mal::Type.new(nil) |
152 | else |
153 | list[2] |
154 | end |
155 | next # TCO |
156 | when "fn*" |
157 | params = list[1].unwrap |
158 | unless params.is_a?(Mal::List) || params.is_a?(Mal::Vector) |
159 | eval_error "'fn*' parameters must be list" |
160 | end |
161 | Mal::Closure.new(list[2], params, env, func_of(env, params, list[2])) |
162 | when "quote" |
163 | list[1] |
164 | when "quasiquote" |
165 | ast = quasiquote list[1] |
166 | next # TCO |
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167 | else |
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168 | invoke_list(list, env) |
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169 | end |
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170 | end |
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171 | end |
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172 | |
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173 | def print(result) |
174 | pr_str(result, true) |
175 | end |
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176 | |
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177 | def rep(str) |
178 | print(eval(read(str), $repl_env)) |
179 | end |
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180 | end |
181 | |
182 | $repl_env = Mal::Env.new nil |
183 | Mal::NS.each{|k,v| $repl_env.set(k, Mal::Type.new(v))} |
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184 | $repl_env.set("eval", Mal::Type.new -> (args: Array(Mal::Type)){ Mal.eval(args[0], $repl_env) }) |
185 | Mal.rep "(def! not (fn* (a) (if a false true)))" |
186 | Mal.rep "(def! load-file (fn* (f) (eval (read-string (str \"(do \" (slurp f) \")\")))))" |
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187 | $argv = Mal::List.new |
188 | $repl_env.set("*ARGV*", Mal::Type.new $argv) |
189 | |
190 | unless ARGV.empty? |
191 | if ARGV.size > 1 |
192 | ARGV[1..-1].each do |a| |
193 | $argv << Mal::Type.new(a) |
194 | end |
195 | end |
196 | |
197 | begin |
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198 | Mal.rep "(load-file \"#{ARGV[0]}\")" |
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199 | rescue e |
200 | STDERR.puts e |
201 | end |
202 | exit |
203 | end |
204 | |
205 | while line = my_readline("user> ") |
206 | begin |
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207 | puts Mal.rep(line) |
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208 | rescue e |
209 | STDERR.puts e |
210 | end |
211 | end |