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1 | import rdstdin, tables, sequtils, os, types, reader, printer, env, core |
2 | |
3 | proc read(str: string): MalType = str.read_str |
4 | |
5 | proc is_pair(x: MalType): bool = |
6 | x.kind in {List, Vector} and x.list.len > 0 |
7 | |
8 | proc quasiquote(ast: MalType): MalType = |
9 | if not ast.is_pair: |
10 | return list(symbol "quote", ast) |
11 | elif ast.list[0] == symbol "unquote": |
12 | return ast.list[1] |
13 | elif ast.list[0].is_pair and ast.list[0].list[0] == symbol "splice-unquote": |
14 | return list(symbol "concat", ast.list[0].list[1], |
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15 | quasiquote(list ast.list[1 .. ^1])) |
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16 | else: |
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17 | return list(symbol "cons", quasiquote(ast.list[0]), quasiquote(list(ast.list[1 .. ^1]))) |
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18 | |
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19 | proc eval(ast: MalType, env: Env): MalType |
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20 | |
21 | proc eval_ast(ast: MalType, env: var Env): MalType = |
22 | case ast.kind |
23 | of Symbol: |
24 | result = env.get(ast.str) |
25 | of List: |
26 | result = list ast.list.mapIt(MalType, it.eval(env)) |
27 | of Vector: |
28 | result = vector ast.list.mapIt(MalType, it.eval(env)) |
29 | of HashMap: |
30 | result = hash_map() |
31 | for k, v in ast.hash_map.pairs: |
32 | result.hash_map[k] = v.eval(env) |
33 | else: |
34 | result = ast |
35 | |
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36 | proc eval(ast: MalType, env: Env): MalType = |
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37 | var ast = ast |
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38 | var env = env |
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39 | |
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40 | template defaultApply = |
41 | let el = ast.eval_ast(env) |
42 | let f = el.list[0] |
43 | case f.kind |
44 | of MalFun: |
45 | ast = f.malfun.ast |
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46 | env = initEnv(f.malfun.env, f.malfun.params, list(el.list[1 .. ^1])) |
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47 | else: |
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48 | return f.fun(el.list[1 .. ^1]) |
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49 | |
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50 | while true: |
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51 | if ast.kind != List: return ast.eval_ast(env) |
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52 | if ast.list.len == 0: return ast |
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53 | |
54 | let a0 = ast.list[0] |
55 | case a0.kind |
56 | of Symbol: |
57 | case a0.str |
58 | of "def!": |
59 | let |
60 | a1 = ast.list[1] |
61 | a2 = ast.list[2] |
62 | return env.set(a1.str, a2.eval(env)) |
63 | |
64 | of "let*": |
65 | let |
66 | a1 = ast.list[1] |
67 | a2 = ast.list[2] |
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68 | var let_env = initEnv(env) |
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69 | case a1.kind |
70 | of List, Vector: |
71 | for i in countup(0, a1.list.high, 2): |
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72 | let_env.set(a1.list[i].str, a1.list[i+1].eval(let_env)) |
73 | else: raise newException(ValueError, "Illegal kind in let*") |
74 | ast = a2 |
75 | env = let_env |
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76 | # Continue loop (TCO) |
77 | |
78 | of "quote": |
79 | return ast.list[1] |
80 | |
81 | of "quasiquote": |
82 | ast = ast.list[1].quasiquote |
83 | # Continue loop (TCO) |
84 | |
85 | of "do": |
86 | let last = ast.list.high |
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87 | discard (list ast.list[1 .. <last]).eval_ast(env) |
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88 | ast = ast.list[last] |
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89 | # Continue loop (TCO) |
90 | |
91 | of "if": |
92 | let |
93 | a1 = ast.list[1] |
94 | a2 = ast.list[2] |
95 | cond = a1.eval(env) |
96 | |
97 | if cond.kind in {Nil, False}: |
98 | if ast.list.len > 3: ast = ast.list[3] |
99 | else: ast = nilObj |
100 | else: ast = a2 |
101 | |
102 | of "fn*": |
103 | let |
104 | a1 = ast.list[1] |
105 | a2 = ast.list[2] |
106 | var env2 = env |
107 | let fn = proc(a: varargs[MalType]): MalType = |
108 | var newEnv = initEnv(env2, a1, list(a)) |
109 | a2.eval(newEnv) |
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110 | return malfun(fn, a2, a1, env) |
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111 | |
112 | else: |
113 | defaultApply() |
114 | |
115 | else: |
116 | defaultApply() |
117 | |
118 | proc print(exp: MalType): string = exp.pr_str |
119 | |
120 | var repl_env = initEnv() |
121 | |
122 | for k, v in ns.items: |
123 | repl_env.set(k, v) |
124 | repl_env.set("eval", fun(proc(xs: varargs[MalType]): MalType = eval(xs[0], repl_env))) |
125 | var ps = commandLineParams() |
126 | repl_env.set("*ARGV*", list((if paramCount() > 1: ps[1..ps.high] else: @[]).map(str))) |
127 | |
128 | |
129 | # core.nim: defined using nim |
130 | proc rep(str: string): string {.discardable.} = |
131 | str.read.eval(repl_env).print |
132 | |
133 | # core.mal: defined using mal itself |
134 | rep "(def! not (fn* (a) (if a false true)))" |
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135 | rep "(def! load-file (fn* (f) (eval (read-string (str \"(do \" (slurp f) \"\nnil)\")))))" |
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136 | |
137 | if paramCount() >= 1: |
138 | rep "(load-file \"" & paramStr(1) & "\")" |
139 | quit() |
140 | |
141 | while true: |
142 | try: |
143 | let line = readLineFromStdin("user> ") |
144 | echo line.rep |
145 | except Blank: discard |
146 | except: |
147 | echo getCurrentExceptionMsg() |
148 | echo getCurrentException().getStackTrace() |