Binary file hws/hw01.pdf has changed

--- a/hws/hw01.tex	Mon Sep 30 12:27:15 2019 +0100
+++ b/hws/hw01.tex	Tue Oct 01 00:29:48 2019 +0100
@@ -21,14 +21,14 @@
       If you want to follow the code I present during the
       lectures, read the handout about Scala.
 
-\item {\bf (Optional)} Have a look at the crawler programs.
-      Can you find a usage for them in your daily programming
-      life? Can you improve them? For example in cases there
-      are links that appear on different recursion levels, the
-      crawlers visit such web-pages several times. Can this be
-      avoided? Also, the crawlers flag as problematic any page
-      that gives an error, but probably only 404 Not Found
-      errors should be flagged. Can you change that?)
+%\item {\bf (Optional)} Have a look at the crawler programs.
+%      Can you find a usage for them in your daily programming
+%      life? Can you improve them? For example in cases there
+%      are links that appear on different recursion levels, the
+%      crawlers visit such web-pages several times. Can this be
+%      avoided? Also, the crawlers flag as problematic any page
+%      that gives an error, but probably only 404 Not Found
+%      errors should be flagged. Can you change that?)
 
 \item Read the handout of the first lecture and the handout
       about notation. Make sure you understand the concepts of

--- a/progs/fun-bare.scala	Mon Sep 30 12:27:15 2019 +0100
+++ b/progs/fun-bare.scala	Tue Oct 01 00:29:48 2019 +0100
@@ -1,12 +1,12 @@
 // A Small Compiler for a Simple Functional Language
 // (it does not include a parser and lexer)
 
-// Abstract syntax trees
+// abstract syntax trees
 abstract class Exp
 abstract class BExp 
 abstract class Decl
 
-// function declarations
+// functions and declarations
 case class Def(name: String, args: List[String], body: Exp) extends Decl
 case class Main(e: Exp) extends Decl
 
@@ -75,10 +75,11 @@
 import scala.language.implicitConversions
 import scala.language.reflectiveCalls
 
+// convenience for code-generation (string interpolations)
 implicit def sring_inters(sc: StringContext) = new {
-  def i(args: Any*): String = "   " ++ sc.s(args:_*) ++ "\n"
-  def l(args: Any*): String = sc.s(args:_*) ++ ":\n"
-  def m(args: Any*): String = sc.s(args:_*) ++ "\n"
+  def i(args: Any*): String = "   " ++ sc.s(args:_*) ++ "\n"  // instructions
+  def l(args: Any*): String = sc.s(args:_*) ++ ":\n"          // labels
+  def m(args: Any*): String = sc.s(args:_*) ++ "\n"           // methods
 }
 
 // variable / index environments
@@ -130,7 +131,7 @@
     compile_exp(a1, env) ++ compile_exp(a2, env) ++ i"if_icmpgt $jmp"
 }
 
-// compile function for declarations and main
+// compile functions and declarations
 def compile_decl(d: Decl) : String = d match {
   case Def(name, args, a) => { 
     val env = args.zipWithIndex.toMap
@@ -164,6 +165,13 @@
 
 
 // An example program (factorials)
+//
+// def fact(n) = if n == 0 then 1 else n * fact(n - 1);
+// def facT(n, acc) = if n == 0 then acc else facT(n - 1, n * acc);
+// 
+// fact(10) ; facT(15, 1)
+// 
+
 
 val test_prog = 
   List(Def("fact", List("n"),