fixes some errors

README.md

@@ -5,18 +5,18 @@
 > A small programming language made with [Scala](https://scala-lang.org) and [ANTLR](https://antlr.org).
 
 This is a simple programming language that has only one loop instruction (while) and a single type (integer).
-We want to show that you can make a programming language with a only few lines of code.
+We want to show how to implement a programming language with a few lines of code.
 
 The language is implemented in two ways:
  - as an [interpreter](interpreter.md)
- - as a [transpiler](transpiler.md) (compiler) for Scala.
+ - as a [transpiler](transpiler.md) (compiler) to Scala.
 
 <table>
   <thead>
     <tr>
       <th> </th>
       <th align="center">Interpreter</th>
-      <th align="center">Compiler (Transpiler)</th>
+      <th align="center">Transpiler (Compiler)</th>
     </tr>
     </thead>
     <tbody>
@@ -40,7 +40,7 @@ The language is implemented in two ways:
     <tr>
       <th>Parser Rules</th>
       <td colspan="2" align="center">
-        <a href="interpreter.md#parser-rules">Listener</a> (58 lines)
+        <a href="interpreter.md#parser-rules">Listener</a> (55 lines)
       </td>
     </tr>
     <tr>
@@ -51,15 +51,15 @@ The language is implemented in two ways:
     <tr>
       <th>Utility Classes</th>
       <td colspan="2" align="center">
-      <a href="interpreter.md#walker">Walker</a> (21 lines)<br>
+      <a href="interpreter.md#walker">Walker</a> (22 lines)<br>
       <a href="interpreter.md#runner">Runner</a> (12 lines)<br>
-      <a href="interpreter.md#contextvalue">Runner</a> (9 lines)
+      <a href="interpreter.md#contextvalue">ContextValue</a> (12 lines)
       </td>
     </tr>
     <tr>
       <th>Total</th>
-      <td align="center">191 lines</td>
-      <td align="center">189 lines</td>
+      <td align="center">192 lines</td>
+      <td align="center">190 lines</td>
     </tr>
   </tbody>
 </table>

src/main/scala/whilelang/compiler/Main.scala

@@ -2,5 +2,6 @@ package whilelang.compiler
 
 import whilelang.util.Runner
 
-@main def main = Runner:
-  program => println(program.meaning)
+val action = Runner(program => println(program.meaning))
+
+@main def main(file: String) = action(file)

src/main/scala/whilelang/interpreter/Main.scala

@@ -2,5 +2,6 @@ package whilelang.interpreter
 
 import whilelang.util.Runner
 
-@main def main = Runner:
-  program => program.execute()
+val action = Runner(program => program.execute())
+
+@main def main(file: String) = action(file)

src/main/scala/whilelang/parser/MyListener.scala

@@ -15,7 +15,7 @@ class MyListener extends BaseListener with ContextValue:
     ctx.seqStatement.value
 
   override def exitSeqStatement(ctx: SeqStatementContext): Unit = ctx.value_= :
-    SeqStatement(ctx.statement.map(_.value[Statement]))
+    SeqStatement(ctx.statement.map(_.value))
 
   override def exitAttrib(ctx: AttribContext): Unit = ctx.value_= :
     Attrib(ctx.ID.text, ctx.expression.value)
@@ -51,8 +51,7 @@ class MyListener extends BaseListener with ContextValue:
     Integer(ctx.text.toInt)
 
   override def exitBinOp(ctx: BinOpContext): Unit = ctx.value_= :
-    val lhs: Expression = ctx.expression(0).value
-    val rhs: Expression = ctx.expression(1).value
+    val Seq(lhs, rhs): Seq[Expression] = ctx.expression.map(_.value)
     ctx(1).text match
       case "*" => ExpMult(lhs, rhs)
       case "-" => ExpSub(lhs, rhs)
@@ -71,8 +70,7 @@ class MyListener extends BaseListener with ContextValue:
     ctx.bool.value
 
   override def exitRelOp(ctx: RelOpContext): Unit = ctx.value_= :
-    val lhs: Expression = ctx.expression(0).value
-    val rhs: Expression = ctx.expression(1).value
+    val Seq(lhs, rhs): Seq[Expression] = ctx.expression.map(_.value)
     ctx(1).text match
-      case "=" => ExpEq(lhs, rhs)
+      case "="      => ExpEq(lhs, rhs)
       case "<=" | _ => ExpLe(lhs, rhs)