Use heuristics to detect whether a block contains a tree

src/main/scala/de/plugh/asciiprooftree/Main.scala

@@ -12,16 +12,21 @@ val lineRe = "^\\s*§(?<block>.*)$".r
 
 class Conf(args: Seq[String]) extends ScallopConf(args):
   val path: ScallopOption[Path] = trailArg[Path]()
-  val indent: ScallopOption[Int] = opt[Int](default = Some(2))
   val blockRegex: ScallopOption[String] = opt[String](default = Some(blockRe.regex))
   val lineRegex: ScallopOption[String] = opt[String](default = Some(lineRe.regex))
+  val indent: ScallopOption[Int] = opt[Int](default = Some(2))
+  val noHeuristics: ScallopOption[Boolean] = opt[Boolean]()
   verify()
 
 @main
 def main(args: String*): Unit =
   val conf = new Conf(args)
-  val formatter =
-    Formatter(indent = conf.indent(), blockRe = Regex(conf.blockRegex()), lineRe = Regex(conf.lineRegex()))
+  val formatter = Formatter(
+    blockRe = Regex(conf.blockRegex()),
+    lineRe = Regex(conf.lineRegex()),
+    indent = conf.indent(),
+    heuristics = !conf.noHeuristics(),
+  )
   reformat(conf.path(), formatter)
 
 def reformat(path: Path, formatter: Formatter): Unit =

src/main/scala/de/plugh/asciiprooftree/file/Formatter.scala

@@ -7,7 +7,7 @@ import scala.util.boundary
 import scala.util.matching.Regex
 import scala.util.matching.Regex.Match
 
-case class Formatter(indent: Int, blockRe: Regex, lineRe: Regex):
+case class Formatter(blockRe: Regex, lineRe: Regex, indent: Int, heuristics: Boolean):
   private val blockReI = blockRe.pattern.namedGroups().get("block")
   private val lineReI = lineRe.pattern.namedGroups().get("block")
 
@@ -26,6 +26,7 @@ case class Formatter(indent: Int, blockRe: Regex, lineRe: Regex):
   private def parseBlock(text: String, m: Match): Option[BlockInfo] = boundary:
     val block = parseBlockLines(m.group(blockReI)).getOrElse(boundary.break(None))
     val tree = Parser(block.content).parse.getOrElse(boundary.break(None))
+    if heuristics && tree.containsNoLines then return None
     Some(BlockInfo(
       block = block,
       tree = tree,

src/main/scala/de/plugh/asciiprooftree/tree/ProofTree.scala

@@ -43,6 +43,8 @@ case class ProofTree(premises: Seq[ProofTree] = Seq(), line: Option[String] = No
 
     combined.copy(conclusionStart = belowCentered.start, conclusionEnd = belowCentered.end)
 
+  def containsNoLines: Boolean = line.isEmpty && premises.forall(_.containsNoLines)
+
 object ProofTree:
   def empty: ProofTree = ProofTree()
   def star: ProofTree = ProofTree().addConclusion("*")