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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 |
53 | |
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54 | macro 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) |
59 | list = ast.unwrap |
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60 | |
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61 | unless 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 | |
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67 | head = list.first.unwrap |
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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 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 | ) |
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79 | else |
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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 | ) |
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84 | end |
85 | end |
86 | |
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87 | def macro_call?(ast, env) |
88 | list = ast.unwrap |
89 | return false unless list.is_a? Mal::List |
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90 | |
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91 | sym = list.first.unwrap |
92 | return false unless sym.is_a? Mal::Symbol |
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93 | |
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94 | func = env.find(sym.str).try(&.data[sym.str]) |
95 | return false unless func && func.macro? |
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96 | |
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97 | true |
98 | end |
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99 | |
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100 | def macroexpand(ast, env) |
101 | while macro_call?(ast, env) |
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102 | |
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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 |
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107 | |
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108 | case func |
109 | when Mal::Func |
110 | ast = func.call(list[1..-1]) |
111 | when Mal::Closure |
112 | ast = func.fn.call(list[1..-1]) |
113 | else |
114 | eval_error "macro '#{func_sym.str}' must be function: #{ast}" |
115 | end |
116 | end |
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117 | |
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118 | ast |
119 | end |
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120 | |
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121 | macro invoke_list(l, env) |
122 | f = eval({{l}}.first, {{env}}).unwrap |
123 | args = eval_ast({{l}}[1..-1].each_with_object(Mal::List.new){|i, l| l << i}, {{env}}) |
124 | case f |
125 | when Mal::Closure |
126 | ast = f.ast |
127 | {{env}} = Mal::Env.new(f.env, f.params, args) |
128 | next # TCO |
129 | when Mal::Func |
130 | return f.call args |
131 | else |
132 | eval_error "expected function as the first argument: #{f}" |
133 | end |
134 | end |
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135 | |
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136 | def eval(ast, env) |
137 | # 'next' in 'do...end' has a bug in crystal 0.7.1 |
138 | # https://github.com/manastech/crystal/issues/659 |
139 | while true |
140 | return eval_ast(ast, env) unless ast.unwrap.is_a? Mal::List |
141 | |
142 | ast = macroexpand(ast, env) |
143 | |
144 | list = ast.unwrap |
145 | |
146 | return ast unless list.is_a? Mal::List |
147 | return ast if list.empty? |
148 | |
149 | head = list.first.unwrap |
150 | |
151 | return invoke_list(list, env) unless head.is_a? Mal::Symbol |
152 | |
153 | return Mal::Type.new case head.str |
154 | when "def!" |
155 | eval_error "wrong number of argument for 'def!'" unless list.size == 3 |
156 | a1 = list[1].unwrap |
157 | eval_error "1st argument of 'def!' must be symbol: #{a1}" unless a1.is_a? Mal::Symbol |
158 | env.set(a1.str, eval(list[2], env)) |
159 | when "let*" |
160 | eval_error "wrong number of argument for 'def!'" unless list.size == 3 |
161 | |
162 | bindings = list[1].unwrap |
163 | eval_error "1st argument of 'let*' must be list or vector" unless bindings.is_a? Array |
164 | eval_error "size of binding list must be even" unless bindings.size.even? |
165 | |
166 | new_env = Mal::Env.new env |
167 | bindings.each_slice(2) do |binding| |
168 | key, value = binding |
169 | name = key.unwrap |
170 | eval_error "name of binding must be specified as symbol #{name}" unless name.is_a? Mal::Symbol |
171 | new_env.set(name.str, eval(value, new_env)) |
172 | end |
173 | |
174 | ast, env = list[2], new_env |
175 | next # TCO |
176 | when "do" |
177 | if list.empty? |
178 | ast = Mal::Type.new nil |
179 | next |
180 | end |
181 | |
182 | eval_ast(list[1..-2].each_with_object(Mal::List.new){|i,l| l << i}, env) |
183 | ast = list.last |
184 | next # TCO |
185 | when "if" |
186 | ast = unless eval(list[1], env).unwrap |
187 | list.size >= 4 ? list[3] : Mal::Type.new(nil) |
188 | else |
189 | list[2] |
190 | end |
191 | next # TCO |
192 | when "fn*" |
193 | params = list[1].unwrap |
194 | unless params.is_a? Array |
195 | eval_error "'fn*' parameters must be list or vector: #{params}" |
196 | end |
197 | Mal::Closure.new(list[2], params, env, func_of(env, params, list[2])) |
198 | when "quote" |
199 | list[1] |
200 | when "quasiquote" |
201 | ast = quasiquote list[1] |
202 | next # TCO |
203 | when "defmacro!" |
204 | eval_error "wrong number of argument for 'defmacro!'" unless list.size == 3 |
205 | a1 = list[1].unwrap |
206 | eval_error "1st argument of 'defmacro!' must be symbol: #{a1}" unless a1.is_a? Mal::Symbol |
207 | env.set(a1.str, eval(list[2], env).tap{|n| n.is_macro = true}) |
208 | when "macroexpand" |
209 | macroexpand(list[1], env) |
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210 | else |
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211 | invoke_list(list, env) |
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212 | end |
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213 | end |
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214 | end |
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215 | |
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216 | def print(result) |
217 | pr_str(result, true) |
218 | end |
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219 | |
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220 | def rep(str) |
221 | print(eval(read(str), $repl_env)) |
222 | end |
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223 | end |
224 | |
225 | $repl_env = Mal::Env.new nil |
226 | Mal::NS.each{|k,v| $repl_env.set(k, Mal::Type.new(v))} |
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227 | $repl_env.set("eval", Mal::Type.new -> (args: Array(Mal::Type)){ Mal.eval(args[0], $repl_env) }) |
228 | Mal.rep "(def! not (fn* (a) (if a false true)))" |
229 | Mal.rep "(def! load-file (fn* (f) (eval (read-string (str \"(do \" (slurp f) \")\")))))" |
230 | 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)))))))" |
231 | Mal.rep "(defmacro! or (fn* (& xs) (if (empty? xs) nil (if (= 1 (count xs)) (first xs) `(let* (or_FIXME ~(first xs)) (if or_FIXME or_FIXME (or ~@(rest xs))))))))" |
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232 | |
233 | $argv = Mal::List.new |
234 | $repl_env.set("*ARGV*", Mal::Type.new $argv) |
235 | |
236 | unless ARGV.empty? |
237 | if ARGV.size > 1 |
238 | ARGV[1..-1].each do |a| |
239 | $argv << Mal::Type.new(a) |
240 | end |
241 | end |
242 | |
243 | begin |
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244 | Mal.rep "(load-file \"#{ARGV[0]}\")" |
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245 | rescue e |
246 | STDERR.puts e |
247 | end |
248 | exit |
249 | end |
250 | |
251 | while line = my_readline("user> ") |
252 | begin |
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253 | puts Mal.rep(line) |
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254 | rescue e |
255 | STDERR.puts e |
256 | end |
257 | end |