Fixed issue #18

Author: xenomachina

CHANGELOG.md

@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
+## Unreleased
+
+### Fixed
+
+- [Issue #18](https://github.com/xenomachina/kotlin-argparser/issues/18)
+
 ## 2.0.2 - 2017-06-12
 
 ### Fixed

src/main/kotlin/com/xenomachina/argparser/ArgParser.kt

@@ -371,6 +371,8 @@ class ArgParser(args: Array<out String>,
         }
 
         internal abstract fun registerLeaf(root: Delegate<*>)
+
+        abstract internal val hasValidators: Boolean
     }
 
     /**

src/main/kotlin/com/xenomachina/argparser/Default.kt

@@ -35,9 +35,16 @@ fun <T> ArgParser.DelegateProvider<T>.default(newDefault: T): ArgParser.Delegate
  * @param newDefault the default value for the resulting [ArgParser.Delegate]
  */
 fun <T> ArgParser.Delegate<T>.default(defaultValue: T): ArgParser.Delegate<T> {
+    if (hasValidators) {
+        throw IllegalStateException("Cannot add default after adding validators")
+    }
     val inner = this
 
     return object : ArgParser.Delegate<T>() {
+
+        override val hasValidators: Boolean
+            get() = inner.hasValidators
+
         override fun toHelpFormatterValue(): HelpFormatter.Value = inner.toHelpFormatterValue().copy(isRequired = false)
 
         override fun validate() {
@@ -63,7 +70,7 @@ fun <T> ArgParser.Delegate<T>.default(defaultValue: T): ArgParser.Delegate<T> {
             get() = inner.help
 
         override fun addValidator(validator: ArgParser.Delegate<T>.() -> Unit): ArgParser.Delegate<T> =
-                inner.addValidator() { validator(inner) }
+                apply { inner.addValidator { validator(this@apply) } }
 
         override fun registerLeaf(root: ArgParser.Delegate<*>) {
             inner.registerLeaf(root)

src/main/kotlin/com/xenomachina/argparser/ParsingDelegate.kt

@@ -31,6 +31,9 @@ internal abstract class ParsingDelegate<T>(
         validators.add(validator)
     }
 
+    override val hasValidators: Boolean
+        get() = validators.isNotEmpty()
+
     override val value: T
         get() {
             parser.force()

src/main/kotlin/com/xenomachina/argparser/WrappingDelegate.kt

@@ -47,6 +47,9 @@ internal class WrappingDelegate<U, W>(
     override fun addValidator(validator: ArgParser.Delegate<W>.() -> Unit): ArgParser.Delegate<W> =
             apply { inner.addValidator { validator(this@WrappingDelegate) } }
 
+    override val hasValidators: Boolean
+        get() = inner.hasValidators
+
     override fun registerLeaf(root: ArgParser.Delegate<*>) {
         inner.registerLeaf(root)
     }

src/test/kotlin/com/xenomachina/argparser/ArgParserTest.kt

@@ -23,6 +23,7 @@ import com.xenomachina.common.orElse
 import io.kotlintest.matchers.beOfType
 import io.kotlintest.matchers.should
 import io.kotlintest.matchers.shouldBe
+import io.kotlintest.matchers.shouldEqual
 import io.kotlintest.matchers.shouldThrow
 import io.kotlintest.specs.FunSpec
 import java.io.File
@@ -1467,4 +1468,33 @@ optional arguments:
 
   --baz QUUX                   test help message""".trim()
     }
-})
+})
+
+class Issue18Test_ValidatorThenDefault : Test({
+    class Args(parser: ArgParser) {
+        val x by parser.storing(
+                "-x",
+                help = TEST_HELP,
+                transform = String::toInt
+        ).addValidator {
+            value shouldEqual 0
+        }.default(0)
+    }
+    shouldThrow<IllegalStateException> {
+        Args(parserOf())
+    }.message shouldEqual "Cannot add default after adding validators"
+})
+
+class Issue18Test_DefaultThenValidator : Test({
+    class Args(parser: ArgParser) {
+        val x by parser.storing(
+                "-x",
+                help = "",
+                transform = String::toInt
+        ).default(0).addValidator {
+            value shouldEqual 0
+        }
+    }
+    val x = Args(parserOf()).x
+    x shouldEqual 0
+})