parser: various code and quality enhancements

ast/src/main/kotlin/gay/pizza/pork/ast/gen/NodeCoalescer.kt

@@ -1,7 +1,7 @@
 // GENERATED CODE FROM PORK AST CODEGEN
 package gay.pizza.pork.ast.gen
 
-class NodeCoalescer(val handler: (Node) -> Unit) : NodeVisitor<Unit> {
+class NodeCoalescer(val followChildren: Boolean = true, val handler: (Node) -> Unit) : NodeVisitor<Unit> {
   override fun visitArgumentSpec(node: ArgumentSpec): Unit =
     handle(node)
 
@@ -97,6 +97,8 @@ class NodeCoalescer(val handler: (Node) -> Unit) : NodeVisitor<Unit> {
 
   fun handle(node: Node) {
     handler(node)
-    node.visitChildren(this)
+    if (followChildren) {
+      node.visitChildren(this)
+    }
   }
 }

buildext/src/main/kotlin/gay/pizza/pork/buildext/ast/AstStandardCodegen.kt

@@ -193,6 +193,11 @@ class AstStandardCodegen(pkg: String, outputDirectory: Path, world: AstWorld) :
       "NodeCoalescer",
       inherits = mutableListOf("NodeVisitor<Unit>"),
       members = mutableListOf(
+        KotlinMember(
+          "followChildren",
+          "Boolean",
+          value = "true"
+        ),
         KotlinMember(
           "handler",
           "(Node) -> Unit"
@@ -227,7 +232,9 @@ class AstStandardCodegen(pkg: String, outputDirectory: Path, world: AstWorld) :
       )
     )
     handleFunction.body.add("handler(node)")
-    handleFunction.body.add("node.visitChildren(this)")
+    handleFunction.body.add("if (followChildren) {")
+    handleFunction.body.add("  node.visitChildren(this)")
+    handleFunction.body.add("}")
     coalescerClass.functions.add(handleFunction)
 
     write("NodeCoalescer.kt", KotlinWriter(coalescerClass))

common/src/main/kotlin/gay/pizza/pork/common/IndentBuffer.kt

@@ -0,0 +1,16 @@
+package gay.pizza.pork.common
+
+class IndentBuffer(
+  val buffer: StringBuilder = StringBuilder(),
+  indent: String = "  "
+) : IndentTracked(indent), Appendable by buffer, CharSequence by buffer {
+  override fun emit(text: String) {
+    append(text)
+  }
+
+  override fun emitLine(text: String) {
+    appendLine(text)
+  }
+
+  override fun toString(): String = buffer.toString()
+}

common/src/main/kotlin/gay/pizza/pork/common/IndentPrinter.kt

@@ -1,36 +1,11 @@
 package gay.pizza.pork.common
 
-class IndentPrinter(
-  val buffer: StringBuilder = StringBuilder(),
-  val indent: String = "  "
-) : Appendable by buffer, CharSequence by buffer {
-  private var indentLevel: Int = 0
-  private var indentLevelText: String = ""
-
-  fun emitIndent() {
-    append(indentLevelText)
-  }
-
-  fun emitIndentedLine(line: String) {
-    emitIndent()
-    appendLine(line)
-  }
-
-  fun increaseIndent() {
-    indentLevel++
-    indentLevelText += indent
-  }
-
-  fun decreaseIndent() {
-    indentLevel--
-    indentLevelText = indent.repeat(indentLevel)
+class IndentPrinter(indent: String = "  ") : IndentTracked(indent) {
+  override fun emit(text: String) {
+    print(text)
   }
 
-  inline fun indented(block: IndentPrinter.() -> Unit) {
-    increaseIndent()
-    block(this)
-    decreaseIndent()
+  override fun emitLine(text: String) {
+    println(text)
   }
-
-  override fun toString(): String = buffer.toString()
 }

common/src/main/kotlin/gay/pizza/pork/common/IndentTracked.kt

@@ -0,0 +1,37 @@
+package gay.pizza.pork.common
+
+abstract class IndentTracked(val indent: String) {
+  private var internalIndentLevel = 0
+  private var indentLevelText = ""
+
+  val indentLevel: Int
+    get() = internalIndentLevel
+
+  fun emitIndent() {
+    emit(indentLevelText)
+  }
+
+  fun emitIndentedLine(line: String) {
+    emitIndent()
+    emitLine(line)
+  }
+
+  fun increaseIndent() {
+    internalIndentLevel++
+    indentLevelText += indent
+  }
+
+  fun decreaseIndent() {
+    internalIndentLevel--
+    indentLevelText = indent.repeat(indentLevel)
+  }
+
+  inline fun indented(block: IndentTracked.() -> Unit) {
+    increaseIndent()
+    block(this)
+    decreaseIndent()
+  }
+
+  abstract fun emit(text: String)
+  abstract fun emitLine(text: String)
+}

evaluator/src/main/kotlin/gay/pizza/pork/evaluator/EvaluationVisitor.kt

@@ -337,7 +337,6 @@ class EvaluationVisitor(root: Scope, val stack: CallStack) : NodeVisitor<Any> {
       InfixOperator.Minus -> subtract(convert(left), convert(right))
       InfixOperator.Multiply -> multiply(convert(left), convert(right))
       InfixOperator.Divide -> divide(convert(left), convert(right))
-      InfixOperator.Equals, InfixOperator.NotEquals, InfixOperator.BooleanAnd, InfixOperator.BooleanOr -> throw RuntimeException("Unable to handle operation $op")
       InfixOperator.BinaryAnd -> binaryAnd(convert(left), convert(right))
       InfixOperator.BinaryOr -> binaryOr(convert(left), convert(right))
       InfixOperator.BinaryExclusiveOr -> binaryExclusiveOr(convert(left), convert(right))
@@ -347,6 +346,8 @@ class EvaluationVisitor(root: Scope, val stack: CallStack) : NodeVisitor<Any> {
       InfixOperator.Greater -> greater(convert(left), convert(right))
       InfixOperator.LesserEqual -> lesserEqual(convert(left), convert(right))
       InfixOperator.GreaterEqual -> greaterEqual(convert(left), convert(right))
+      InfixOperator.Equals, InfixOperator.NotEquals, InfixOperator.BooleanAnd, InfixOperator.BooleanOr ->
+        throw RuntimeException("Unable to handle operation $op")
     }
   }
 

parser/src/main/kotlin/gay/pizza/pork/parser/CharConsumer.kt

@@ -0,0 +1,5 @@
+package gay.pizza.pork.parser
+
+interface CharConsumer {
+  fun consume(type: TokenType, tokenizer: Tokenizer): String?
+}

parser/src/main/kotlin/gay/pizza/pork/parser/CharSource.kt

@@ -1,8 +1,10 @@
 package gay.pizza.pork.parser
 
 interface CharSource : PeekableSource<Char> {
+  fun peek(index: Int): Char
+
   companion object {
     @Suppress("ConstPropertyName")
-    const val NullChar = 0.toChar()
+    const val EndOfFile = 0.toChar()
   }
 }

parser/src/main/kotlin/gay/pizza/pork/parser/CharSourceExtensions.kt

@@ -1,7 +1,7 @@
 package gay.pizza.pork.parser
 
 fun CharSource.readToString(): String = buildString {
-  while (peek() != CharSource.NullChar) {
+  while (peek() != CharSource.EndOfFile) {
     append(next())
   }
 }

parser/src/main/kotlin/gay/pizza/pork/parser/MatchedCharConsumer.kt

@@ -0,0 +1,48 @@
+package gay.pizza.pork.parser
+
+@Suppress("CanBeParameter")
+class MatchedCharConsumer(
+  val start: CharSequence,
+  val end: CharSequence,
+  vararg val options: Options
+) : CharConsumer {
+  private val eofTerminationAllowed = options.contains(Options.AllowEofTermination)
+
+  override fun consume(type: TokenType, tokenizer: Tokenizer): String? {
+    if (!tokenizer.peek(start)) {
+      return null
+    }
+    val buffer = StringBuilder()
+    tokenizer.read(start.length, buffer)
+    var endsNeededToTerminate = 1
+    while (true) {
+      if (tokenizer.peek(start)) {
+        endsNeededToTerminate++
+        tokenizer.read(start.length, buffer)
+        continue
+      }
+
+      if (tokenizer.peek(end)) {
+        endsNeededToTerminate--
+        tokenizer.read(end.length, buffer)
+      }
+
+      if (endsNeededToTerminate == 0) {
+        return buffer.toString()
+      }
+
+      val char = tokenizer.source.next()
+      if (char == CharSource.EndOfFile) {
+        if (eofTerminationAllowed) {
+          return buffer.toString()
+        }
+        throw UnterminatedTokenError(type.name, tokenizer.source.currentSourceIndex())
+      }
+      buffer.append(char)
+    }
+  }
+
+  enum class Options {
+    AllowEofTermination
+  }
+}