some support for LaTeX;

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/Pure/Thy/latex.scala	Fri Dec 08 23:43:58 2017 +0100
@@ -0,0 +1,60 @@
+/*  Title:      Pure/Thy/latex.scala
+    Author:     Makarius
+
+Support for LaTeX.
+*/
+
+package isabelle
+
+
+import scala.annotation.tailrec
+
+
+object Latex
+{
+  sealed case class Error(file: Option[Path], line: Int, message: String)
+
+  def filter_errors(dir: Path, text: String): List[Error] =
+  {
+    object File_Line_Error
+    {
+      val Pattern = """^(.*):(\d+): (.*)$""".r
+      def unapply(line: String): Option[Error] =
+        line match {
+          case Pattern(file, Value.Int(line), message) =>
+            val path = File.standard_path(file)
+            if (Path.is_wellformed(path)) {
+              val file = Path.explode(path)
+              if ((dir + file).is_file) Some(Error(Some(file), line, message)) else None
+            }
+            else None
+          case _ => None
+        }
+    }
+
+    object Line_Error
+    {
+      val Pattern = """^l\.(\d+) (.*)$""".r
+      def unapply(line: String): Option[Error] =
+        line match {
+          case Pattern(Value.Int(line), message) => Some(Error(None, line, message))
+          case _ => None
+        }
+    }
+
+    @tailrec def filter(lines: List[String], result: List[Error]): List[Error] =
+      lines match {
+        case File_Line_Error(err1) :: rest1 =>
+          rest1 match {
+            case Line_Error(err2) :: rest2 if err1.line == err2.line =>
+              val err = err1.copy(message = Exn.cat_message(err1.message, err2.message))
+              filter(rest2, err :: result)
+            case _ => filter(rest1, err1 :: result)
+          }
+        case _ :: rest => filter(rest, result)
+        case Nil => result.reverse
+      }
+
+    filter(split_lines(text), Nil)
+  }
+}

--- a/src/Pure/build-jars	Fri Dec 08 17:57:29 2017 +0100
+++ b/src/Pure/build-jars	Fri Dec 08 23:43:58 2017 +0100
@@ -126,6 +126,7 @@
   System/progress.scala
   System/system_channel.scala
   Thy/html.scala
+  Thy/latex.scala
   Thy/present.scala
   Thy/sessions.scala
   Thy/thy_header.scala