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