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import scala.util.matching.Regex
import types.{MalList, _list, MalVector, _vector, MalHashMap, _hash_map}
object reader {
class Reader (tokens: Array[String]) {
var data = tokens
var position: Int = 0
def peek(): String = {
if (position >= data.length) return(null)
data(position)
}
def next(): String = {
if (position >= data.length) return(null)
position = position + 1
data(position-1)
}
}
def tokenize(str: String): Array[String] = {
val re = """[\s,]*(~@|[\[\]{}()'`~^@]|"(?:\\.|[^\\"])*"|;.*|[^\s\[\]{}('"`,;)]*)""".r
re.findAllMatchIn(str).map{ _.group(1) }
.filter{ s => s != "" && s(0) != ';' }
.toArray
}
def parse_str(s: String): String = {
s.replace("\\\"", "\"").replace("\\n", "\n")
}
def read_atom(rdr: Reader): Any = {
val token = rdr.next()
val re_int = """^(-?[0-9]+)$""".r
val re_flt = """^(-?[0-9][0-9.]*)$""".r
val re_str = """^"(.*)"$""".r
val re_key = """^:(.*)$""".r
return token match {
case re_int(i) => i.toLong // integer
case re_flt(f) => f.toDouble // float
case re_str(s) => parse_str(s) // string
case re_key(k) => "\u029e" + k // keyword
case "nil" => null
case "true" => true
case "false" => false
case _ => Symbol(token) // symbol
}
}
def read_list(rdr: Reader,
start: String = "(", end: String = ")"): MalList = {
var ast: MalList = _list()
var token = rdr.next()
if (token != start) throw new Exception("expected '" + start + "', got EOF")
while ({token = rdr.peek(); token != end}) {
if (token == null) throw new Exception("expected '" + end + "', got EOF")
ast = ast :+ read_form(rdr)
}
rdr.next()
ast
}
def read_form(rdr: Reader): Any = {
return rdr.peek() match {
case "'" => { rdr.next; _list(Symbol("quote"), read_form(rdr)) }
case "`" => { rdr.next; _list(Symbol("quasiquote"), read_form(rdr)) }
case "~" => { rdr.next; _list(Symbol("unquote"), read_form(rdr)) }
case "~@" => { rdr.next; _list(Symbol("splice-unquote"), read_form(rdr)) }
case "^" => { rdr.next; val meta = read_form(rdr);
_list(Symbol("with-meta"), read_form(rdr), meta) }
case "@" => { rdr.next; _list(Symbol("deref"), read_form(rdr)) }
case "(" => read_list(rdr)
case ")" => throw new Exception("unexpected ')')")
case "[" => _vector(read_list(rdr, "[", "]").value:_*)
case "]" => throw new Exception("unexpected ']')")
case "{" => _hash_map(read_list(rdr, "{", "}").value:_*)
case "}" => throw new Exception("unexpected '}')")
case _ => read_atom(rdr)
}
}
def read_str(str: String): Any = {
val tokens = tokenize(str)
if (tokens.length == 0) return null
return read_form(new Reader(tokens))
}
}
// vim: ts=2:sw=2
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