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SQLParser.scala
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SQLParser.scala
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package com.log4p.sqldsl
import scala.util.parsing.combinator._
import scala.util.parsing.combinator.syntactical._
class SQLParser extends JavaTokenParsers {
def query:Parser[Query] = operation ~ from ~ opt(where) ~ opt(order) ^^ {
case operation ~ from ~ where ~ order => Query(operation, from, where, order)
}
def operation:Parser[Operation] = {
("select" | "update" | "delete") ~ repsep(ident, ",") ^^ {
case "select" ~ f => Select(f:_*)
case _ => throw new IllegalArgumentException("Operation not implemented")
}
}
def from:Parser[From] = "from" ~> ident ^^ (From(_))
def where:Parser[Where] = "where" ~> rep(clause) ^^ (Where(_:_*))
def clause:Parser[Clause] = (predicate|parens) * (
"and" ^^^ { (a:Clause, b:Clause) => And(a,b) } |
"or" ^^^ { (a:Clause, b:Clause) => Or(a,b) }
)
def parens:Parser[Clause] = "(" ~> clause <~ ")"
def predicate = (
ident ~ "=" ~ boolean ^^ { case f ~ "=" ~ b => BooleanEquals(f,b)}
| ident ~ "=" ~ stringLiteral ^^ { case f ~ "=" ~ v => StringEquals(f,stripQuotes(v))}
| ident ~ "=" ~ wholeNumber ^^ { case f ~ "=" ~ i => NumberEquals(f,i.toInt)}
)
def boolean = ("true" ^^^ (true) | "false" ^^^ (false))
def order:Parser[Direction] = {
"order" ~> "by" ~> ident ~ ("asc" | "desc") ^^ {
case f ~ "asc" => Asc(f)
case f ~ "desc" => Desc(f)
}
}
def stripQuotes(s:String) = s.substring(1, s.length-1)
def parse(sql:String):Option[Query] = {
parseAll(query, sql) match {
case Success(r, q) => Option(r)
case x => println(x); None
}
}
}