src/Pure/Thy/thy_load.scala

simplified Document.Node.Header -- internalized errors;

/*  Title:      Pure/Thy/thy_load.scala
    Author:     Makarius

Primitives for loading theory files.
*/

package isabelle


import java.io.{File => JFile}


object Thy_Load
{
  def thy_path(path: Path): Path = path.ext("thy")

  def is_ok(str: String): Boolean =
    try { thy_path(Path.explode(str)); true }
    catch { case ERROR(_) => false }
}


class Thy_Load(preloaded: Set[String] = Set.empty)
{
  /* loaded theories provided by prover */

  private var loaded_theories: Set[String] = preloaded

  def register_thy(thy_name: String): Unit =
    synchronized { loaded_theories += thy_name }

  def is_loaded(thy_name: String): Boolean =
    synchronized { loaded_theories.contains(thy_name) }


  /* file-system operations */

  def append(dir: String, source_path: Path): String =
    (Path.explode(dir) + source_path).implode

  def read_header(name: Document.Node.Name): Thy_Header =
  {
    val file = new JFile(name.node)
    if (!file.exists || !file.isFile) error("No such file: " + quote(file.toString))
    Thy_Header.read(file)
  }


  /* theory files */

  private def import_name(dir: String, s: String): Document.Node.Name =
  {
    val theory = Thy_Header.base_name(s)
    if (is_loaded(theory)) Document.Node.Name(theory, "", theory)
    else {
      val path = Path.explode(s)
      val node = append(dir, Thy_Load.thy_path(path))
      val dir1 = append(dir, path.dir)
      Document.Node.Name(node, dir1, theory)
    }
  }

  def check_header(name: Document.Node.Name, header: Thy_Header): Document.Node.Header =
  {
    val name1 = header.name
    val imports = header.imports.map(import_name(name.dir, _))
    // FIXME val uses = header.uses.map(p => (append(name.dir, Path.explode(p._1)), p._2))
    val uses = header.uses
    if (name.theory != name1)
      error("Bad file name " + Thy_Load.thy_path(Path.basic(name.theory)) +
        " for theory " + quote(name1))
    Document.Node.Header(imports, header.keywords, uses)
  }

  def check_thy(name: Document.Node.Name): Document.Node.Header =
    check_header(name, read_header(name))
}