Rename literal effect to write (#1294)

Co-authored-by: Tim Süberkrüb <dev@timsueberkrueb.io>

Author: phischu

effekt/jvm/src/test/scala/effekt/LSPTests.scala

@@ -811,7 +811,7 @@ class LSPTests extends FunSuite {
         raw"""effect raise(): Unit
              |
              |↑
-             |def foo() = { do raise(); 5 }
+             |def boo() = { do raise(); 5 }
              |         ↑
              |
              |↑

effekt/shared/src/main/scala/effekt/Parser.scala

@@ -1350,7 +1350,7 @@ class Parser(tokens: Seq[Token], source: Source) {
       backtrack(idRef()) ~ template() match {
         // We do not need to apply any transformation if there are no splices _and_ no custom handler id is given
         case Maybe(None, _) ~ SpannedTemplate(str :: Nil, Nil) => StringLit(str.unspan, str.span)
-        // s"a${x}b${y}" ~> s { do literal("a"); do splice(x); do literal("b"); do splice(y); return () }
+        // s"a${x}b${y}" ~> s { do write("a"); do splice(x); do write("b"); do splice(y); return () }
         case Maybe(id, range) ~ SpannedTemplate(strs, args) =>
           val target = id match {
             case Some(id) => id
@@ -1362,7 +1362,7 @@ class Parser(tokens: Seq[Token], source: Source) {
           }
           val doLits = strs.map { s =>
             Do(
-              IdRef(Nil, "literal", s.span.synthesized),
+              IdRef(Nil, "write", s.span.synthesized),
               Nil,
               List(ValueArg.Unnamed(StringLit(s.unspan, s.span))),
               Nil,

examples/benchmarks/other/nbe.effekt

@@ -94,19 +94,14 @@ def parse(): Term / { read[Bool], stop } = {
 }
 
 /// helper function for pretty string interpolation of terms
-def pretty { s: () => Unit / { literal, splice[Term] } }: String = {
+def pretty { stream: () => Unit / { write, splice[Term] } }: String = {
   with stringBuffer
-
-  try { s(); do flush() }
-  with literal { l => resume(do write(l)) }
-  with splice[Term] { t =>
-    t match {
-      case Abs(n, t) => do write("λ" ++ n.show ++ pretty".${t}")
-      case App(a, b) => do write(pretty"(${a} ${b})")
-      case Var(v)    => do write(v.show)
-    }
-    resume(())
+  with splicing[Term] {
+    case Abs(n, t) => do write("λ" ++ n.show ++ pretty".${t}")
+    case App(a, b) => do write(pretty"(${a} ${b})")
+    case Var(v)    => do write(v.show)
   }
+  stream()
 }
 
 /// convert char stream to bit stream, skipping non-bit chars

examples/pos/string_interpolation.effekt

@@ -4,33 +4,26 @@ type Expr {
   App(fn: Expr, arg: Expr)
 }
 
-def pretty { prog: () => Unit / {literal, splice[Expr]} }: String = {
+def pretty { prog: () => Unit / {write, splice[Expr]} }: String = {
   with stringBuffer
-  try {
-    prog()
-    do flush()
-  } with literal { s =>
-    resume(do write(s))
-  } with splice[Expr] { expr =>
-    expr match {
-      case Var(id) =>
-        do write(id)
-      case App(Abs(param, body), arg) =>
-        do write(pretty"(${Abs(param, body)}) ${arg}")
-      case App(fn, arg) =>
-        do write(pretty"${fn} ${arg}")
-      case Abs(param, body) =>
-        do write(s"\\ ${param} -> " ++ pretty"${body}")
-    }
-    resume(())
+  with splicing[Expr] {
+    case Var(id) =>
+      do write(id)
+    case App(Abs(param, body), arg) =>
+      do write(pretty"(${Abs(param, body)}) ${arg}")
+    case App(fn, arg) =>
+      do write(pretty"${fn} ${arg}")
+    case Abs(param, body) =>
+      do write(s"\\ ${param} -> " ++ pretty"${body}")
   }
+  prog()
 }
 
-def len { prog: () => Unit / {literal} }: Int = {
+def len { prog: () => Unit / write }: Int = {
   try {
     prog()
     0
-  } with literal { s =>
+  } with write { s =>
     s.length
   }
 }

examples/pos/string_interpolation_literal.effekt

@@ -1,13 +1,13 @@
 effect log(msg: String): Unit
 
-def error { body: => Unit / literal }: Unit / log =
-  try body() with literal { x => do log("[ERROR] " ++ x); resume(()) }
+def error { body: => Unit / write }: Unit / log =
+  try body() with write { x => do log("[ERROR] " ++ x); resume(()) }
 
-def warn { body: => Unit / literal }: Unit / log =
-  try body() with literal { x => do log("[WARNING] " ++ x); resume(()) }
+def warn { body: => Unit / write }: Unit / log =
+  try body() with write { x => do log("[WARNING] " ++ x); resume(()) }
 
-def doc { body: => Unit / {literal} }: Unit =
-  try body() with literal { _ => resume(()) }
+def doc { body: => Unit / write }: Unit =
+  try body() with write { _ => resume(()) }
 
 def main() = try {
   doc"This is the doc string for my main function!"

libraries/common/effekt.effekt

@@ -790,17 +790,18 @@ def locally[R] { p: => R } : R = p()
 //
 //     "foo ${42} bar ${43}"
 //
-// to the following stream of `literal`s and `splice[Int]`s:
+// to the following stream of `write`s and `splice[Int]`s:
 //
-//     do literal("foo "); do splice(42); do literal(" bar "); do splice(43)
+//     do write("foo "); do splice(42); do write(" bar "); do splice(43)
 //
 // The stream is wrapped into a handler function, which defaults to `stringbuffer::s`
 //
 //    s { ... }
 //
 // but can be specified by prefixing the string interpolation `custom"..."`.
 
-effect literal(s: String): Unit
+effect write(s: String): Unit
+
 effect splice[A](x: A): Unit
 
 

libraries/common/stringbuffer.effekt

@@ -3,60 +3,58 @@ module stringbuffer
 import effekt
 import bytearray
 
-interface StringBuffer {
-  def write(str: String): Unit
-  def flush(): String
-}
+effect flush(): String
+
+def stringBuffer { program: () => Unit / write }: String =
+  flushableStringBuffer { program(); do flush() }
 
-def stringBuffer[A] { prog: => A / StringBuffer }: A = {
+def flushableStringBuffer[A] { program: () => A / { write, flush } }: A = {
   val initialCapacity = 128
   var buffer = bytearray::allocate(initialCapacity)
   // next free index to write to
-  var pos = 0
+  var position = 0
 
-  def ensureCapacity(sizeToAdd: Int): Unit = {
-    val cap = buffer.size - pos
-    if (sizeToAdd <= cap) ()
+  def ensureCapacity(required: Int): Unit = {
+    val capacity = buffer.size - position
+    if (required <= capacity) ()
     else {
       // Double the capacity while ensuring the required capacity
-      val newSize = max(buffer.size * 2, buffer.size + sizeToAdd)
+      val newSize = max(buffer.size * 2, buffer.size + required)
       buffer = buffer.resize(newSize)
     }
   }
 
-  try { prog() }
-  with StringBuffer {
-    def write(str) = {
-      val bytes = fromString(str)
-      ensureCapacity(bytes.size)
-      bytes.foreach { b =>
-        buffer.set(pos, b)
-        pos = pos + 1
-      }
-      resume(())
-    }
-    def flush() = {
-      // resize (& copy) buffer to strip trailing zeros that otherwise would be converted into 0x00 characters
-      val str = bytearray::resize(buffer, pos).toString()
-      // NOTE: Keep the `buffer` as-is (no wipe, no realloc),
-      //       just reset the `pos` in case we want to use it again.
-      pos = 0
-      resume(str)
+  try {
+    program()
+  } with write { string =>
+    val bytes = fromString(string)
+    ensureCapacity(bytes.size)
+    bytes.foreach { b =>
+      buffer.set(position, b)
+      position = position + 1
     }
+    resume(())
+  } with flush {
+    val string = buffer.resize(position).toString()
+    position = 0
+    resume(string)
   }
 }
 
+def splicing[T] { writer: T => Unit } { program: () => Unit / splice[T] }: Unit =
+  try { program() } with splice[T] { t => resume(writer(t)) }
+
+
 /// Handler for string interpolation using a string buffer
-def s { prog: () => Unit / { literal, splice[String] } }: String =
+def s { program: () => Unit / { write, splice[String] } }: String =
   stringBuffer {
-    try { prog(); do flush() }
+    try { program() }
     with splice[String] { x => resume(do write(x)) }
-    with literal { s => resume(do write(s)) }
   }
 
 namespace examples {
   def main() = {
-    with stringBuffer
+    with flushableStringBuffer
 
     do write("hello")
     do write(", world")