mirror of
https://github.com/kanaka/mal.git
synced 2024-11-10 12:47:45 +03:00
72 lines
1.8 KiB
Nim
72 lines
1.8 KiB
Nim
import rdstdin, tables, sequtils, types, reader, printer, env
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proc read(str: string): MalType = str.read_str
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proc eval(ast: MalType, env: var Env): MalType
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proc eval_ast(ast: MalType, env: var Env): MalType =
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case ast.kind
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of Symbol:
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result = env.get(ast.str)
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of List:
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result = list ast.list.mapIt(MalType, it.eval(env))
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of Vector:
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result = vector ast.list.mapIt(MalType, it.eval(env))
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of HashMap:
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result = hash_map()
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for k, v in ast.hash_map.pairs:
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result.hash_map[k] = v.eval(env)
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else:
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result = ast
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proc eval(ast: MalType, env: var Env): MalType =
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case ast.kind
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of List:
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if ast.list.len == 0: return ast
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let
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a0 = ast.list[0]
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a1 = ast.list[1]
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a2 = ast.list[2]
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case a0.str
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of "def!":
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result = env.set(a1.str, a2.eval(env))
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of "let*":
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var letEnv: Env
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letEnv.deepCopy(env)
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case a1.kind
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of List, Vector:
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for i in countup(0, a1.list.high, 2):
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letEnv.set(a1.list[i].str, a1.list[i+1].eval(letEnv))
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else: discard
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result = a2.eval(letEnv)
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else:
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let el = ast.eval_ast(env)
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result = el.list[0].fun(el.list[1 .. ^1])
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else:
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result = ast.eval_ast(env)
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proc print(exp: MalType): string = exp.pr_str
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template wrapNumberFun(op: expr): expr =
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fun proc(xs: varargs[MalType]): MalType = number op(xs[0].number, xs[1].number)
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var repl_env = initEnv()
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repl_env.set("+", wrapNumberFun(`+`))
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repl_env.set("-", wrapNumberFun(`-`))
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repl_env.set("*", wrapNumberFun(`*`))
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repl_env.set("/", wrapNumberFun(`div`))
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#repl_env.set("/", wrapNumberFun(proc(x,y: int): int = int(x.float / y.float)))
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proc rep(str: string): string =
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str.read.eval(repl_env).print
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while true:
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try:
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let line = readLineFromStdin("user> ")
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echo line.rep
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except:
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echo getCurrentExceptionMsg()
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echo getCurrentException().getStackTrace()
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