f5cf5237 |
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 is_macro_call(ast: MalType, env: Env): bool = |
20 | ast.kind == List and ast.list[0].kind == Symbol and |
21 | env.find(ast.list[0].str) != nil and env.get(ast.list[0].str).macro_q |
22 | |
23 | proc macroexpand(ast: MalType, env: Env): MalType = |
24 | result = ast |
25 | while result.is_macro_call(env): |
26 | let mac = env.get(result.list[0].str) |
27 | result = mac.malfun.fn(result.list[1 .. -1]).macroexpand(env) |
28 | |
29 | proc eval(ast: MalType, env: var Env): MalType |
30 | |
31 | proc eval_ast(ast: MalType, env: var Env): MalType = |
32 | case ast.kind |
33 | of Symbol: |
34 | result = env.get(ast.str) |
35 | of List: |
36 | result = list ast.list.mapIt(MalType, it.eval(env)) |
37 | of Vector: |
38 | result = vector ast.list.mapIt(MalType, it.eval(env)) |
39 | of HashMap: |
40 | result = hash_map() |
41 | for k, v in ast.hash_map.pairs: |
42 | result.hash_map[k] = v.eval(env) |
43 | else: |
44 | result = ast |
45 | |
46 | proc eval(ast: MalType, env: var Env): MalType = |
47 | template defaultApply = |
48 | let el = ast.eval_ast(env) |
49 | let f = el.list[0] |
50 | case f.kind |
51 | of MalFun: |
52 | ast = f.malfun.ast |
53 | env = initEnv(env, f.malfun.params, list(el.list[1 .. -1])) |
54 | else: |
55 | return f.fun(el.list[1 .. -1]) |
56 | |
57 | var ast = ast |
58 | while true: |
59 | if ast.kind != List: return ast.eval_ast(env) |
60 | |
61 | ast = ast.macroexpand(env) |
62 | if ast.kind != List: return ast |
63 | if ast.list.len == 0: return ast |
64 | |
65 | let a0 = ast.list[0] |
66 | case a0.kind |
67 | of Symbol: |
68 | case a0.str |
69 | of "def!": |
70 | let |
71 | a1 = ast.list[1] |
72 | a2 = ast.list[2] |
73 | return env.set(a1.str, a2.eval(env)) |
74 | |
75 | of "let*": |
76 | let |
77 | a1 = ast.list[1] |
78 | a2 = ast.list[2] |
79 | var let_env = Env(env) |
80 | case a1.kind |
81 | of List, Vector: |
82 | for i in countup(0, a1.list.high, 2): |
83 | let_env.set(a1.list[i].str, a1.list[i+1].eval(let_env)) |
84 | else: raise newException(ValueError, "Illegal kind in let*") |
85 | ast = a2 |
86 | env = let_env |
87 | # Continue loop (TCO) |
88 | |
89 | of "quote": |
90 | return ast.list[1] |
91 | |
92 | of "quasiquote": |
93 | ast = ast.list[1].quasiquote |
94 | # Continue loop (TCO) |
95 | |
96 | of "defmacro!": |
97 | var fun = ast.list[2].eval(env) |
98 | fun.malfun.is_macro = true |
99 | return env.set(ast.list[1].str, fun) |
100 | |
101 | of "macroexpand": |
102 | return ast.list[1].macroexpand(env) |
103 | |
104 | of "do": |
105 | let last = ast.list.high |
106 | let el = (list ast.list[1 .. <last]).eval_ast(env) |
107 | ast = ast.list[last].eval(env) |
108 | # Continue loop (TCO) |
109 | |
110 | of "if": |
111 | let |
112 | a1 = ast.list[1] |
113 | a2 = ast.list[2] |
114 | cond = a1.eval(env) |
115 | |
116 | if cond.kind in {Nil, False}: |
117 | if ast.list.len > 3: ast = ast.list[3] |
118 | else: ast = nilObj |
119 | else: ast = a2 |
120 | |
121 | of "fn*": |
122 | let |
123 | a1 = ast.list[1] |
124 | a2 = ast.list[2] |
125 | var env2 = env |
126 | let fn = proc(a: varargs[MalType]): MalType = |
127 | var newEnv = initEnv(env2, a1, list(a)) |
128 | a2.eval(newEnv) |
129 | return malfun(fn, a2, a1, env2) |
130 | |
131 | else: |
132 | defaultApply() |
133 | |
134 | else: |
135 | defaultApply() |
136 | |
137 | proc print(exp: MalType): string = exp.pr_str |
138 | |
139 | var repl_env = initEnv() |
140 | |
141 | for k, v in ns.items: |
142 | repl_env.set(k, v) |
143 | repl_env.set("eval", fun(proc(xs: varargs[MalType]): MalType = eval(xs[0], repl_env))) |
144 | var ps = commandLineParams() |
145 | repl_env.set("*ARGV*", list((if paramCount() > 1: ps[1..ps.high] else: @[]).map(str))) |
146 | |
147 | |
148 | # core.nim: defined using nim |
149 | proc rep(str: string): string {.discardable.} = |
150 | str.read.eval(repl_env).print |
151 | |
152 | # core.mal: defined using mal itself |
153 | rep "(def! not (fn* (a) (if a false true)))" |
154 | rep "(def! load-file (fn* (f) (eval (read-string (str \"(do \" (slurp f) \")\")))))" |
155 | 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)))))))" |
156 | 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))))))))" |
157 | |
158 | if paramCount() >= 1: |
159 | rep "(load-file \"" & paramStr(1) & "\")" |
160 | quit() |
161 | |
162 | while true: |
163 | try: |
164 | let line = readLineFromStdin("user> ") |
165 | echo line.rep |
166 | except Blank: discard |
167 | except: |
168 | echo getCurrentExceptionMsg() |
169 | echo getCurrentException().getStackTrace() |