mirror of
https://github.com/kanaka/mal.git
synced 2024-09-20 18:18:51 +03:00
69 lines
1.8 KiB
Io
69 lines
1.8 KiB
Io
MalTypes
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MalReader
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READ := method(str, MalReader read_str(str))
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eval_ast := method(ast, env,
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(ast type) switch(
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"MalSymbol", env get(ast),
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"MalList", MalList with(ast map(a, EVAL(a, env))),
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"MalVector", MalVector with(ast map(a, EVAL(a, env))),
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"MalMap",
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m := MalMap clone
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ast foreach(k, v,
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keyObj := MalMap keyToObj(k)
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m atPut(MalMap objToKey(EVAL(keyObj, env)), EVAL(v, env))
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)
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m,
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ast
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)
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)
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EVAL := method(ast, env,
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if(ast type != "MalList", return(eval_ast(ast, env)))
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if(ast at(0) type == "MalSymbol",
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ast at(0) val switch(
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"def!",
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return(env set(ast at(1), EVAL(ast at(2), env))),
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"let*",
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letEnv := Env with(env)
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varName := nil
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ast at(1) foreach(i, e,
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if(i % 2 == 0,
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varName := e,
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letEnv set(varName, EVAL(e, letEnv))
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)
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)
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return(EVAL(ast at(2), letEnv))
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)
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)
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// Apply
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el := eval_ast(ast, env)
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f := el at(0)
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args := el rest
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f callWithArgList(args)
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)
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PRINT := method(exp, exp malPrint(true))
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repl_env := Env with(nil)
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repl_env set(MalSymbol with("+"), block(a, b, a + b))
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repl_env set(MalSymbol with("-"), block(a, b, a - b))
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repl_env set(MalSymbol with("*"), block(a, b, a * b))
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repl_env set(MalSymbol with("/"), block(a, b, a / b))
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RE := method(str, EVAL(READ(str), repl_env))
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REP := method(str, PRINT(RE(str)))
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loop(
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line := MalReadline readLine("user> ")
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if(line isNil, break)
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if(line isEmpty, continue)
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e := try(REP(line) println)
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e catch(Exception,
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("Error: " .. (e error)) println
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)
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)
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