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94 lines
3.0 KiB
Plaintext
94 lines
3.0 KiB
Plaintext
--- step7_quote ---------------------------------
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import types, reader, printer, env, core
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READ(str): return reader.read_str(str)
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pair?(ast): return ... // true if non-empty sequence
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quasiquote(ast): return ... // quasiquote
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eval_ast(ast,env):
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switch type(ast):
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symbol: return env.get(ast)
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list,vector: return ast.map((x) -> EVAL(x,env))
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hash: return ast.map((k,v) -> list(k, EVAL(v,env)))
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_default_: return ast
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EVAL(ast,env):
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while true:
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if not list?(ast): return eval_ast(ast, env)
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if empty?(ast): return ast
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switch ast[0]:
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'def!: return env.set(ast[1], EVAL(ast[2], env))
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'let*: env = ...; ast = ast[2] // TCO
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'quote: return ast[1]
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'quasiquote: ast = quasiquote(ast[1]) // TCO
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'do: ast = eval_ast(ast[1..-1], env)[-1] // TCO
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'if: EVAL(ast[1], env) ? ast = ast[2] : ast = ast[3] // TCO
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'fn*: return new MalFunc(...)
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_default_: f, args = eval_ast(ast, env)
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if malfunc?(f): ast = f.fn; env = ... // TCO
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else: return apply(f, args)
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PRINT(exp): return printer.pr_str(exp)
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repl_env = new Env()
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rep(str): return PRINT(EVAL(READ(str),repl_env))
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;; core.EXT: defined using Racket
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core.ns.map((k,v) -> (repl_env.set(k, v)))
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repl_env.set('eval, (ast) -> EVAL(ast, repl-env))
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repl_env.set('*ARGV*, cmdline_args[1..])
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;; core.mal: defined using the language itself
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rep("(def! not (fn* (a) (if a false true)))")
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rep("(def! load-file (fn* (f) (eval (read-string (str \"(do \" (slurp f) \")\")))))")
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if cmdline_args: rep("(load-file \"" + args[0] + "\")"); exit 0
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main loop:
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try: println(rep(readline("user> ")))
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catch e: println("Error: ", e)
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--- env module ----------------------------------
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class Env (outer=null,binds=[],exprs=[])
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data = hash_map()
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foreach b, i in binds:
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if binds[i] == '&: data[binds[i+1]] = exprs.drop(i); break
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else: data[binds[i]] = exprs[i]
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set(k,v): return data.set(k,v)
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find(k): return data.has(k) ? this : (if outer ? find(outer) : null)
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get(k): return data.find(k).get(k) OR raise "'" + k + "' not found"
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--- core module ---------------------------------
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ns = {'=: equal?,
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'pr-str: (a) -> a.map(|s| pr_str(e,true)).join(" ")),
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'str: (a) -> a.map(|s| pr_str(e,false)).join("")),
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'prn: (a) -> println(a.map(|s| pr_str(e,true)).join(" ")),
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'println: (a) -> println(a.map(|s| pr_str(e,false)).join(" ")),
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'read-string: read_str,
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'slurp read-file,
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'<: lt,
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'<=: lte,
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'>: gt,
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'>=: gte,
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'+: add,
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'-: sub,
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'*: mult,
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'/: div,
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'list: list,
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'list?: list?,
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'cons: (a) -> concat([a[0]], a[1]),
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'concat: (a) -> reduce(concat, [], a),
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'empty?: empty?,
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'count: count,
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'atom: (a) -> new Atom(a[0]),
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'atom?: (a) -> type(a[0]) == "atom",
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'deref: (a) -> a[0].val,
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'reset!: (a) -> a[0].val = a[1],
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'swap!: swap!}
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