simplified syntax and provide a proper parser

1 files changed, 50 insertions, 0 deletions

diff --git a/src/main/scala/cc/spray/boilerplate/TemplateParser.scala b/src/main/scala/cc/spray/boilerplate/TemplateParser.scala
new file mode 100644
index 0000000..4e280a4
--- /dev/null
+++ b/src/main/scala/cc/spray/boilerplate/TemplateParser.scala
@@ -0,0 +1,50 @@
+package cc.spray.boilerplate
+
+import util.parsing.combinator.RegexParsers
+import java.lang.RuntimeException
+
+sealed trait TemplateElement
+case class Sequence(elements: Seq[TemplateElement]) extends TemplateElement
+case class LiteralString(literal: String) extends TemplateElement
+case class FixedString(literal: String) extends TemplateElement
+case class Expand(inner: TemplateElement, separator: String) extends TemplateElement
+
+object TemplateParser extends RegexParsers {
+  override type Elem = Char
+  type Tokens = TemplateElement
+  override val skipWhitespace = false
+
+  def elements: Parser[TemplateElement] = rep1(element) ^^ {
+    case one :: Nil => one
+    case several => Sequence(several)
+  }
+
+  def element: Parser[TemplateElement] = literal | fixed | expand
+
+  def literalChar: Parser[String] = """(?s:(?!\[#)(?!#[^\]]*\]).)""".r
+  def literalChars: Parser[String] = rep1(literalChar) ^^ { _.reduceLeft(_ + _) }
+
+  def literal: Parser[LiteralString] = literalChars ^^ LiteralString
+
+  def fixed: Parser[FixedString] = "##" ~> ".".r ^^ (new String(_)) ^^ FixedString
+
+  def expand: Parser[Expand] = "[#" ~> elements ~ "#" ~ separatorChars <~ "]" ^^ {
+    case els ~ x ~ sep => Expand(els, sep.getOrElse(", "))
+  }
+
+  def separatorChars: Parser[Option[String]] = rep("""[^\]]""".r) ^^ (_.reduceLeftOption(_ + _))
+
+  def parse(input:String): TemplateElement =
+    phrase(elements)(new scala.util.parsing.input.CharArrayReader(input.toCharArray)) match {
+      case Success(res,_) => res
+      case x:NoSuccess => throw new RuntimeException(x.msg)
+    }
+}
+
+object TestParser extends App {
+  def check(format: String) {
+    println(TemplateParser.parse(format))
+  }
+
+  check("[#abc ##1 # ++ ]")
+}
\ No newline at end of file