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