diff --git a/lib/language/ic/checker.effekt b/lib/language/ic/checker.effekt
index eb12d8f..59da999 100644
--- a/lib/language/ic/checker.effekt
+++ b/lib/language/ic/checker.effekt
@@ -2,28 +2,28 @@ import map
 
 import lib/language/ic/term
 
-def checkPolarities(): Unit / { Exception[WrongFormat], read[Constructor], emit[Constructor] } = {
+def checkPolarities(): Unit / { Exception[WrongFormat], next[Constructor], emit[Constructor] } = {
   var map: Map[String, Polarity] = emptyGeneric()
 
   def check(port: Port) = {
     map.get(port.name) match {
       case Some(Pos()) and port.pol is Neg() => map = map.delete(port.name)
       case Some(Neg()) and port.pol is Pos() => map = map.delete(port.name)
-      case Some(_) => wrongFormat("invalid '${port.pol.show}'-polarity of ${port.name}")
+      case Some(_) => wrongFormat(s"invalid '${port.pol.show}'-polarity of ${port.name}")
       case None() => map = map.put(port.name, port.pol)
     }
   }
 
   loop {
-    val ctor = do read()
+    val ctor = do next()
     println(ctor.show)
     ctor.pp.check()
     ctor.aux.foreach { p => p.check() }
     do emit(ctor)
   }
 
-  if (map.size > 1) wrongFormat("only 1 wire is allowed to be free, but ${map.size.show} are")
+  if (map.size > 1) wrongFormat(s"only 1 wire is allowed to be free, but ${map.size.show} are")
 }
 
-def check!(): Unit / { Exception[WrongFormat], read[Constructor], emit[Constructor] } =
+def check!(): Unit / { Exception[WrongFormat], next[Constructor], emit[Constructor] } =
   checkPolarities()
\ No newline at end of file
diff --git a/lib/language/ic/compiler.effekt b/lib/language/ic/compiler.effekt
index 2c5de4e..82c90cb 100644
--- a/lib/language/ic/compiler.effekt
+++ b/lib/language/ic/compiler.effekt
@@ -7,7 +7,7 @@ import lib/language/ic/parser
 import lib/language/ic/checker
 import lib/language/ic/uniquifier
 
-def compile!(): Unit / { Exception[WrongFormat], read[Char], emit[Constructor] } =
+def compile!(): Unit / { Exception[WrongFormat], next[Char], emit[Constructor] } =
   with source[Constructor] { parse!() }
   with source[Constructor] { check!() }
   uniquify!()
\ No newline at end of file
diff --git a/lib/language/ic/parser.effekt b/lib/language/ic/parser.effekt
index a3e9568..30889a9 100644
--- a/lib/language/ic/parser.effekt
+++ b/lib/language/ic/parser.effekt
@@ -47,12 +47,12 @@ def parseS(input: String): List[Constructor] / Exception[WrongFormat] =
     }
     def fail(msg) = Error(WrongFormat(), msg)
   }
-  with LexerError { (msg, pos) => Error(WrongFormat(), "${pos.show}: ${msg}") }
+  with LexerError { (msg, pos) => Error(WrongFormat(), s"${pos.show}: ${msg}") }
   .value
 
 // TODO: also support parsing rules (emit[Rule])
 //   "! f-(a-, k+) <> f+(x+, b-) ~> [a-/x-][k-/b-]"
 // TODO: we sometimes swallow parsing errors because everything is streamed, is there an easy fix?
-def parse!(): Unit / { Exception[WrongFormat], read[Char], emit[Constructor] } = {
-  parseS(collect { loop { do emit(do read[Char]()) } }).each
+def parse!(): Unit / { Exception[WrongFormat], next[Char], emit[Constructor] } = {
+  parseS(collect { loop { do emit(do next[Char]()) } }).each
 }
\ No newline at end of file
diff --git a/lib/language/ic/ruler.effekt b/lib/language/ic/ruler.effekt
index 09efe6a..0542cd5 100644
--- a/lib/language/ic/ruler.effekt
+++ b/lib/language/ic/ruler.effekt
@@ -89,16 +89,16 @@ val icRules = [
       })),
     ] else [
       ManyFinally(LeftBiased(box { (i, ai) =>
-        val ais = m.list::build { i => Port("${ai.name}_${i.show}", Pos()) }.reverse
+        val ais = m.list::build { i => Port(s"${ai.name}_${i.show}", Pos()) }.reverse
         do constructor(ai, ais, DarkTriangle()) // DUP
       }), Symmetric(box { (i, k, f) =>
-        val ks = m.list::build { i => Port("${k.name}_${i.show}", Neg()) }.reverse
+        val ks = m.list::build { i => Port(s"${k.name}_${i.show}", Neg()) }.reverse
         do constructor(k, ks, DarkTriangle()) // SUP
       })),
       Many(RightBiased(box { (i, fj) => if (i <= m) {
         val k = do left(n - 1)
-        val ki = Port("${k.name}_${i.show}", Pos())
-        val ais = (n - 1).list::build { j => Port("${do left(j).name}_${i.show}", Neg()) }
+        val ki = Port(s"${k.name}_${i.show}", Pos())
+        val ais = (n - 1).list::build { j => Port(s"${do left(j).name}_${i.show}", Neg()) }
         do constructor(fj, ais.append(singleton(ki)), LightTriangle()) // APP
       }}))
     ]
@@ -107,7 +107,7 @@ val icRules = [
   // k-(k1+, ..., km+) <> k+(x1+, ..., xn+, b-) ~> b-(b1+, ..., bm+), x1+(x11-, ..., x1m-), ..., xn+(xn1-, ..., xnm-), // DUP, SUPs
   //                                               k1+(x11+, ..., xn1+, b1-), ..., km+(x1m+, ..., xnm+, bm-)           // LAMs
   // lambda commutation duplicator in LC: DUP-LAM
-  Rule(DarkTriangle(), LightTriangle(), box { (m, n) => 
+  Rule(DarkTriangle(), LightTriangle(), box { (m, n) =>
     if (m == 0) [
       Many(RightBiased(box { (i, xbi) =>
         do constructor(xbi, [], DarkTriangle())
@@ -119,16 +119,16 @@ val icRules = [
       })),
     ] else [
       ManyFinally(RightBiased(box { (i, xi) =>
-        val xis = m.list::build { i => Port("${xi.name}_${i.show}", Neg()) }.reverse
+        val xis = m.list::build { i => Port(s"${xi.name}_${i.show}", Neg()) }.reverse
         do constructor(xi, xis, DarkTriangle()) // DUP
       }), Symmetric(box { (i, k, b) =>
-        val bs = m.list::build { i => Port("${b.name}_${i.show}", Pos()) }.reverse
+        val bs = m.list::build { i => Port(s"${b.name}_${i.show}", Pos()) }.reverse
         do constructor(b, bs, DarkTriangle()) // SUP
       })),
       Many(LeftBiased(box { (i, ki) => if (i <= m) {
         val b = do right(n - 1)
-        val bi = Port("${b.name}_${i.show}", Neg())
-        val xis = (n - 1).list::build { j => Port("${do right(j).name}_${i.show}", Pos()) }
+        val bi = Port(s"${b.name}_${i.show}", Neg())
+        val xis = (n - 1).list::build { j => Port(s"${do right(j).name}_${i.show}", Pos()) }
         do constructor(ki, xis.append(singleton(bi)), LightTriangle())
       }}))
     ]
diff --git a/lib/language/ic/uniquifier.effekt b/lib/language/ic/uniquifier.effekt
index 2a6b9fd..4e455ed 100644
--- a/lib/language/ic/uniquifier.effekt
+++ b/lib/language/ic/uniquifier.effekt
@@ -1,8 +1,8 @@
 import lib/language/ic/term
 
 // TODO: actually uniquify (not really required though if the user is nice)
-def uniquify!(): Unit / { read[Constructor], emit[Constructor] } = {
+def uniquify!(): Unit / { next[Constructor], emit[Constructor] } = {
   loop {
-    do emit(do read())
+    do emit(do next())
   }
 }
\ No newline at end of file
diff --git a/lib/language/lc/compiler.effekt b/lib/language/lc/compiler.effekt
index 2db4506..a99bbd7 100644
--- a/lib/language/lc/compiler.effekt
+++ b/lib/language/lc/compiler.effekt
@@ -6,6 +6,6 @@ import lib/language/lc/parser
 import lib/language/lc/netter
 import lib/language/ic/term
 
-def compile!(): Unit / { Exception[WrongFormat], read[Char], emit[Constructor] } =
+def compile!(): Unit / { Exception[WrongFormat], next[Char], emit[Constructor] } =
   with source[Term] { parse!() }
   net!()
\ No newline at end of file
diff --git a/lib/language/lc/netter.effekt b/lib/language/lc/netter.effekt
index 4e4b41c..2c30916 100644
--- a/lib/language/lc/netter.effekt
+++ b/lib/language/lc/netter.effekt
@@ -20,11 +20,11 @@ def plumbing { prog: => Unit / port } = {
   }
 }
 
-def net!(): Unit / { Exception[WrongFormat], read[Term], emit[Constructor] } = {
+def net!(): Unit / { Exception[WrongFormat], next[Term], emit[Constructor] } = {
   with plumbing
   with loop
 
-  val term = do read[Term]()
+  val term = do next[Term]()
   // println("term: '${term.show}'")
 
   def bind(bindings: Map[String, List[Port]], x: String): Label = {
@@ -33,7 +33,7 @@ def net!(): Unit / { Exception[WrongFormat], read[Term], emit[Constructor] } = {
 
     val duplicity = bound.size
     duplicity match {
-      case 0 => 
+      case 0 =>
         val pk = do port(x ++ "Era")
         do emit(Constructor(Port(pk, Neg()), [], DarkTriangle()))
         pk
diff --git a/lib/language/lc/parser.effekt b/lib/language/lc/parser.effekt
index 49a1dc2..dcdbd40 100644
--- a/lib/language/lc/parser.effekt
+++ b/lib/language/lc/parser.effekt
@@ -42,8 +42,8 @@ def parseS(input: String): List[Term] / Exception[WrongFormat] =
     }
     def fail(msg) = Error(WrongFormat(), msg)
   }
-  with LexerError { (msg, pos) => Error(WrongFormat(), "${pos.show}: ${msg}") }
+  with LexerError { (msg, pos) => Error(WrongFormat(), s"${pos.show}: ${msg}") }
   .value
 
-def parse!(): Unit / { Exception[WrongFormat], read[Char], emit[Term] } =
-  parseS(collect { loop { do emit(do read[Char]()) } }).each
\ No newline at end of file
+def parse!(): Unit / { Exception[WrongFormat], next[Char], emit[Term] } =
+  parseS(collect { loop { do emit(do next[Char]()) } }).each
\ No newline at end of file
diff --git a/lib/language/parser.effekt b/lib/language/parser.effekt
index 2d363ac..44dbd34 100644
--- a/lib/language/parser.effekt
+++ b/lib/language/parser.effekt
@@ -12,7 +12,7 @@ effect Parser = { Nondet, Lexer }
 def accept { p: Token => Bool } : Token / Parser = {
   val got = do next();
   if (p(got)) got
-  else do fail("Unexpected ${got.show} token")
+  else do fail(s"Unexpected ${got.show} token")
 }
 
 def any() = accept { t => true }
diff --git a/lib/net/layout.effekt b/lib/net/layout.effekt
index f1f2a5c..75741e1 100644
--- a/lib/net/layout.effekt
+++ b/lib/net/layout.effekt
@@ -12,7 +12,7 @@ def coulombForce(agent: Agent) { agents: => Unit / AgentStream }: Vector / Force
   with forceSum
   with source[Vector] { agentPositions {agents} }
   with loop
-  do emit(repulsion(do read[Vector], agent.pos))
+  do emit(repulsion(do next[Vector], agent.pos))
 
 def geometry(wire: Wire) { agents: => Unit / AgentStream }: (Vector, Vector) = {
   val (from, to) = wire.fromTo {agents}
diff --git a/lib/net/netter.effekt b/lib/net/netter.effekt
index bd2c92e..4fdfb30 100644
--- a/lib/net/netter.effekt
+++ b/lib/net/netter.effekt
@@ -10,7 +10,7 @@ def circularLayout(k: Int): Vector = {
   Vector((k.mod(3) + 1).toDouble * scale, (k.mod(3) + 1).toDouble * scale).rotate(k.toDouble)
 }
 
-def net!(): Unit / { read[Constructor], NetStream } = {
+def net!(): Unit / { next[Constructor], NetStream } = {
   var ids: Label = 0
   var map: Map[String, Label] = emptyGeneric()
 
@@ -31,7 +31,7 @@ def net!(): Unit / { read[Constructor], NetStream } = {
   var k = 0
 
   with loop
-  val ctor = do read()
+  val ctor = do next()
   val pp_ = ctor.pp.uniqueMatch()
   val aux_ = ctor.aux.map { p => p.uniqueMatch() }
   do emit(Agent(ctor.pp.name, pp_, aux_, ctor.kind, circularLayout(k)))
diff --git a/lib/ui/vector.effekt b/lib/ui/vector.effekt
index 7738786..e2f2447 100644
--- a/lib/ui/vector.effekt
+++ b/lib/ui/vector.effekt
@@ -2,11 +2,11 @@
 
 record Vector(x: Double, y: Double)
 
-def infixAdd(v1: Vector, v2: Vector) = Vector(v1.x + v2.x, v1.y + v2.y)
-def infixSub(v1: Vector, v2: Vector) = Vector(v1.x - v2.x, v1.y - v2.y)
-def infixAdd(v: Vector, s: Double) = Vector(v.x + s, v.y + s)
-def infixMul(v: Vector, s: Double) = Vector(v.x * s, v.y * s)
-def infixDiv(v: Vector, s: Double) = Vector(v.x / s, v.y / s)
+def infixPlus(v1: Vector, v2: Vector) = Vector(v1.x + v2.x, v1.y + v2.y)
+def infixMinus(v1: Vector, v2: Vector) = Vector(v1.x - v2.x, v1.y - v2.y)
+def infixPlus(v: Vector, s: Double) = Vector(v.x + s, v.y + s)
+def infixStar(v: Vector, s: Double) = Vector(v.x * s, v.y * s)
+def infixSlash(v: Vector, s: Double) = Vector(v.x / s, v.y / s)
 
 def dot(v1: Vector, v2: Vector) = (v1.x * v2.x) + (v1.y * v2.y)
 def magnitude(v: Vector) = sqrt(v.dot(v))
diff --git a/lib/ui/view.effekt b/lib/ui/view.effekt
index 2364f47..688fc11 100644
--- a/lib/ui/view.effekt
+++ b/lib/ui/view.effekt
@@ -156,8 +156,8 @@ def run[St, Ev](root: Node, init: St, app: View[St, Ev]) = {
       def merge(current: Node, fresh: Node) = {
         with on[MissingValue].ignore // can happen on race conditions
         dirtyTags.get.toList.sort.reverse.foreach { tag =>
-          current.querySelector("[data-tag='${tag.show}']").value.replaceWith(
-            fresh.querySelector("[data-tag='${tag.show}']").value
+          current.querySelector(s"[data-tag='${tag.show}']").value.replaceWith(
+            fresh.querySelector(s"[data-tag='${tag.show}']").value
           )
         }
       }
diff --git a/lib/utils.effekt b/lib/utils.effekt
index 65c2179..57231b7 100644
--- a/lib/utils.effekt
+++ b/lib/utils.effekt
@@ -2,12 +2,6 @@
 
 import test
 
-// println without the ln: only for jsNode, of course
-extern def print(s: String) at io: Unit =
-  jsNode "process.stdout.write(${s})"
-  jsWeb "console.log(${s})"
-  default { println(s) }
-
 def size[A] { s: => Unit / emit[A] }: Int = {
   var size = 0
   try s()
@@ -25,12 +19,6 @@ def choose[A] { stream: () => Unit / emit[A] }: A / fail =
     else resume(())
   }
 
-def init[A](l: List[A]): List[A] / Exception[MissingValue] = l match {
-  case Nil() => do raise(MissingValue(), "Trying to get the beginning of an empty list")
-  case Cons(a, Nil()) => Nil()
-  case Cons(a, as) => Cons(a, as.init)
-}
-
 def exhaustively[R](init: R) { program: () => R / fail }: R =
   var res: R = init
   try {
@@ -42,15 +30,3 @@ def exhaustively[R](init: R) { program: () => R / fail }: R =
   } with fail {
     res
   }
-
-def assertNotThrown[E](ex: on[E]) { body: => Unit / Exception[E] }: Unit / Assertion =
-  ex.default { do assert(false, "Unexpected Exception") } {body}
-
-def assertNoThrow[E] { body: => Unit / Exception[E] }: Unit / Assertion =
-  on[E].default{ do assert(false, "Unexpected Exception") } {body}
-
-def assertThrown[E](ex: on[E]) { body: => Unit / Exception[E] }: Unit / Assertion =
-  do assert(ex.default { true } { body(); false }, "Expected Exception, but exited normally")
-
-def assertThrows[E] { body: => Unit / Exception[E] }: Unit / Assertion =
-  do assert(on[E].default { true } { body(); false }, "Expected Exception, but exited normally")