[SPARK-10533][SQL] handle scientific notation in sqlParser

https://issues.apache.org/jira/browse/SPARK-10533

val df = sqlContext.createDataFrame(Seq(("a",1.0),("b",2.0),("c",3.0)))
df.filter("_2 < 2.0e1").show

Scientific notation didn't work.

Author: Daoyuan Wang <daoyuan.wang@intel.com>

Closes #9085 from adrian-wang/scinotation.

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/AbstractSparkSQLParser.scala

@@ -82,6 +82,10 @@ class SqlLexical extends StdLexical {
     override def toString: String = chars
   }
 
+  case class DecimalLit(chars: String) extends Token {
+    override def toString: String = chars
+  }
+
   /* This is a work around to support the lazy setting */
   def initialize(keywords: Seq[String]): Unit = {
     reserved.clear()
@@ -102,8 +106,12 @@ class SqlLexical extends StdLexical {
   }
 
   override lazy val token: Parser[Token] =
-    ( identChar ~ (identChar | digit).* ^^
-      { case first ~ rest => processIdent((first :: rest).mkString) }
+    ( rep1(digit) ~ ('.' ~> digit.*).? ~ (exp ~> sign.? ~ rep1(digit)) ^^ {
+        case i ~ None ~ (sig ~ rest) =>
+          DecimalLit(i.mkString + "e" + sig.mkString + rest.mkString)
+        case i ~ Some(d) ~ (sig ~ rest) =>
+          DecimalLit(i.mkString + "." + d.mkString + "e" + sig.mkString + rest.mkString)
+      }
     | digit.* ~ identChar ~ (identChar | digit).* ^^
       { case first ~ middle ~ rest => processIdent((first ++ (middle :: rest)).mkString) }
     | rep1(digit) ~ ('.' ~> digit.*).? ^^ {
@@ -125,6 +133,9 @@ class SqlLexical extends StdLexical {
 
   override def identChar: Parser[Elem] = letter | elem('_')
 
+  private lazy val sign: Parser[Elem] = elem("s", c => c == '+' || c == '-')
+  private lazy val exp: Parser[Elem] = elem("e", c => c == 'E' || c == 'e')
+
   override def whitespace: Parser[Any] =
     ( whitespaceChar
     | '/' ~ '*' ~ comment

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/SqlParser.scala

@@ -337,6 +337,9 @@ object SqlParser extends AbstractSparkSQLParser with DataTypeParser {
     | sign.? ~ unsignedFloat ^^ {
       case s ~ f => Literal(toDecimalOrDouble(s.getOrElse("") + f))
     }
+    | sign.? ~ unsignedDecimal ^^ {
+      case s ~ d => Literal(toDecimalOrDouble(s.getOrElse("") + d))
+    }
     )
 
   protected lazy val unsignedFloat: Parser[String] =
@@ -344,6 +347,14 @@ object SqlParser extends AbstractSparkSQLParser with DataTypeParser {
     | elem("decimal", _.isInstanceOf[lexical.FloatLit]) ^^ (_.chars)
     )
 
+  protected lazy val unsignedDecimal: Parser[String] =
+    ( "." ~> decimalLit ^^ { u => "0." + u }
+    | elem("scientific_notation", _.isInstanceOf[lexical.DecimalLit]) ^^ (_.chars)
+    )
+
+  def decimalLit: Parser[String] =
+    elem("scientific_notation", _.isInstanceOf[lexical.DecimalLit]) ^^ (_.chars)
+
   protected lazy val sign: Parser[String] = ("+" | "-")
 
   protected lazy val integral: Parser[String] =

sql/core/src/test/scala/org/apache/spark/sql/DataFrameSuite.scala

@@ -177,9 +177,14 @@ class DataFrameSuite extends QueryTest with SharedSQLContext {
   }
 
   test("filterExpr") {
-    checkAnswer(
-      testData.filter("key > 90"),
-      testData.collect().filter(_.getInt(0) > 90).toSeq)
+    val res = testData.collect().filter(_.getInt(0) > 90).toSeq
+    checkAnswer(testData.filter("key > 90"), res)
+    checkAnswer(testData.filter("key > 9.0e1"), res)
+    checkAnswer(testData.filter("key > .9e+2"), res)
+    checkAnswer(testData.filter("key > 0.9e+2"), res)
+    checkAnswer(testData.filter("key > 900e-1"), res)
+    checkAnswer(testData.filter("key > 900.0E-1"), res)
+    checkAnswer(testData.filter("key > 9.e+1"), res)
   }
 
   test("filterExpr using where") {