Print help for '-help' too (#310)

alexarchambault · Jul 23, 2021 · 1b90b2a · 1b90b2a
1 parent 0e6db57
commit 1b90b2a
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Showing 6 changed files with 92 additions and 12 deletions.
diff --git a/core/shared/src/main/scala/caseapp/core/help/Help.scala b/core/shared/src/main/scala/caseapp/core/help/Help.scala
@@ -247,10 +247,14 @@ object Help {
 
   private def optionsTable(args: Seq[Arg], format: HelpFormat, nameFormatter: Formatter[Name], showHidden: Boolean): Seq[Seq[fansi.Str]] =
     for (arg <- args if showHidden || !arg.noHelp) yield {
-      val sortedNames = (arg.name +: arg.extraNames).groupBy(_.name.length).toVector.sortBy(_._1).flatMap(_._2)
+      val sortedNames = (arg.name +: arg.extraNames)
+        .map(name => format.option(name.option(nameFormatter)))
+        .groupBy(_.length)
+        .toVector
+        .sortBy(_._1)
+        .flatMap(_._2)
       val options = sortedNames
         .iterator
-        .map(name => format.option(name.option(nameFormatter)))
         .zip(Iterator.continually(", ": fansi.Str))
         .flatMap { case (a, b) => Iterator(a, b) }
         .toVector

diff --git a/core/shared/src/main/scala/caseapp/core/help/WithHelp.scala b/core/shared/src/main/scala/caseapp/core/help/WithHelp.scala
@@ -1,7 +1,12 @@
 package caseapp.core.help
 
-import caseapp.core.Error
-import caseapp.{ExtraName, Group, HelpMessage, Recurse}
+import caseapp.{ExtraName, Group, Help, HelpMessage, Parser, Recurse}
+import caseapp.core.parser.{Argument, NilParser, StandardArgument}
+import caseapp.core.{Arg, Error}
+import caseapp.core.parser.{EitherParser, RecursiveConsParser}
+import caseapp.core.util.Formatter
+
+import shapeless.{HNil, :: => :*:}
 
 /**
   * Helper to add `--usage` and `--help` options to an existing type `T`.
@@ -25,3 +30,57 @@ final case class WithHelp[T](
   def map[U](f: T => U): WithHelp[U] =
     copy(baseOrError = baseOrError.map(f))
 }
+
+object WithHelp {
+
+  implicit def parser[T, D](implicit underlying: Parser.Aux[T, D]): Parser.Aux[WithHelp[T], Option[Boolean] :*: Option[Boolean] :*: D :*: HNil] = {
+
+    val usageArgument = StandardArgument[Boolean](
+      Arg("usage")
+        .withGroup(Some(Group("Help")))
+        .withOrigin(Some("WithHelp"))
+        .withHelpMessage(Some(HelpMessage("Print usage and exit")))
+        .withIsFlag(true)
+    ).withDefault(() => Some(false))
+
+    val baseHelpArgument = StandardArgument[Boolean](
+      Arg("help")
+        .withExtraNames(Seq(ExtraName("h"), ExtraName("-help")))
+        .withGroup(Some(Group("Help")))
+        .withOrigin(Some("WithHelp"))
+        .withHelpMessage(Some(HelpMessage("Print help message and exit")))
+        .withIsFlag(true)
+    ).withDefault(() => Some(false))
+
+    // accept "-help" too (single dash)
+    val helpArgument: Argument[Boolean] =
+      new Argument[Boolean] {
+        def arg = baseHelpArgument.arg
+        def withDefaultOrigin(origin: String) =
+          this
+        def init = baseHelpArgument.init
+        def step(
+            args: List[String],
+            d: Option[Boolean],
+            nameFormatter: Formatter[ExtraName]
+        ): Either[(Error, List[String]), Option[(Option[Boolean], List[String])]] =
+          args match {
+            case "-help" :: rem => Right(Some((Some(true), rem)))
+            case _ => baseHelpArgument.step(args, d, nameFormatter)
+          }
+        def get(d: Option[Boolean], nameFormatter: Formatter[ExtraName]) =
+          baseHelpArgument.get(d, nameFormatter)
+      }
+
+    val either = EitherParser[T, D](underlying)
+
+    val p = usageArgument ::
+      helpArgument ::
+      RecursiveConsParser(either, NilParser)
+
+    p.to[WithHelp[T]]
+  }
+
+  implicit def help[T, D](implicit parser: Parser.Aux[T, D], underlying: Help[T]): Help[WithHelp[T]] =
+    Help.derive[WithHelp[T]]
+}
diff --git a/core/shared/src/main/scala/caseapp/core/parser/RecursiveConsParser.scala b/core/shared/src/main/scala/caseapp/core/parser/RecursiveConsParser.scala
@@ -53,6 +53,9 @@ import dataclass.data
       f(l.head) :: l.tail
     }
 
+  def ::[A](argument: Argument[A]): ConsParser[A, H :: T, D] =
+    ConsParser[A, H :: T, D](argument, this)
+
   def withDefaultOrigin(origin: String): Parser.Aux[H :: T, D] =
     withHeadParser(headParser.withDefaultOrigin(origin))
       .withTailParser(tailParser.withDefaultOrigin(origin))

diff --git a/core/shared/src/main/scala/caseapp/package.scala b/core/shared/src/main/scala/caseapp/package.scala
@@ -8,6 +8,7 @@
 package object caseapp {
 
   type ExtraName = Name
+  val ExtraName = Name
 
   type Parser[T] = core.parser.Parser[T]
   val Parser = core.parser.Parser

diff --git a/tests/shared/src/test/scala/caseapp/CaseAppTests.scala b/tests/shared/src/test/scala/caseapp/CaseAppTests.scala
@@ -514,6 +514,19 @@ object CaseAppTests extends TestSuite {
       assert(messageOpt.contains("Unrecognized argument: --help"))
     }
 
+    test("accept -help") {
+      val res =
+        Parser[FewArgs].withHelp.detailedParse(
+          Seq("-help")
+        )
+
+      val expectedRes =
+        Right(
+          (WithHelp(false, true, Right(FewArgs())), RemainingArgs(List(), List()))
+        )
+      assert(res == expectedRes)
+    }
+
   }
 
 }
diff --git a/tests/shared/src/test/scala/caseapp/HelpTests.scala b/tests/shared/src/test/scala/caseapp/HelpTests.scala
@@ -257,8 +257,8 @@ object HelpTests extends TestSuite {
         """Usage: foo <COMMAND> [options]
           |
           |Help options:
-          |  --usage     Print usage and exit
-          |  -h, --help  Print help message and exit
+          |  --usage            Print usage and exit
+          |  -h, -help, --help  Print help message and exit
           |
           |Other options:
           |  -f, --foo string
@@ -283,8 +283,8 @@ object HelpTests extends TestSuite {
         """Usage: foo <COMMAND> [options]
           |
           |Help options:
-          |  --usage     Print usage and exit
-          |  -h, --help  Print help message and exit
+          |  --usage            Print usage and exit
+          |  -h, -help, --help  Print help message and exit
           |
           |Other options:
           |  -f, --foo string
@@ -312,8 +312,8 @@ object HelpTests extends TestSuite {
           """Usage: foo <COMMAND> [options]
             |
             |Help options:
-            |  --usage     Print usage and exit
-            |  -h, --help  Print help message and exit
+            |  --usage            Print usage and exit
+            |  -h, -help, --help  Print help message and exit
             |
             |Other options:
             |  -f, --foo string
@@ -333,8 +333,8 @@ object HelpTests extends TestSuite {
           """Usage: foo <COMMAND> [options]
             |
             |Help options:
-            |  --usage     Print usage and exit
-            |  -h, --help  Print help message and exit
+            |  --usage            Print usage and exit
+            |  -h, -help, --help  Print help message and exit
             |
             |Other options:
             |  -f, --foo string