Refactor code

src/main/kotlin/error/ErrorManager.kt

@@ -3,8 +3,6 @@ package error
 import environment.RuntimeEnvironment
 import error.Severity.CRITICAL
 import error.Severity.WARNING
-import java.io.PrintStream
-import java.text.MessageFormat.format
 
 /**
  * Prints error messages and potentially terminates the application.
@@ -23,14 +21,13 @@ class ErrorManager {
         output.println(formatMessage(lispException))
     }
 
-    private fun selectOutputStream(severity: Severity): PrintStream {
-        return if (severity === WARNING) RuntimeEnvironment.output!! else RuntimeEnvironment.errorOutput!!
-    }
+    private fun selectOutputStream(severity: Severity) =
+        if (severity === WARNING) RuntimeEnvironment.output!! else RuntimeEnvironment.errorOutput!!
 
     private fun formatMessage(lispException: LispException): String {
         val severity = lispException.severity
         val prefix = severity.toDisplayString()
-        val message = format("[{0}] {1}", prefix, lispException.message)
+        val message = "[$prefix] ${lispException.message}"
 
         return severity.decorate(message, RuntimeEnvironment)
     }

src/main/kotlin/error/LineColumnException.kt

@@ -1,12 +1,11 @@
 package error
 
 import file.FilePosition
-import java.text.MessageFormat.format
 
 abstract class LineColumnException(private val position: FilePosition) : LispException() {
 
     abstract val messagePrefix: String
 
     override val message: String
-        get() = format("{0} - line {1}, column {2}", messagePrefix, position.lineNumber, position.columnNumber)
+        get() = "$messagePrefix - line ${position.lineNumber}, column ${position.columnNumber}"
 }

src/main/kotlin/token/TokenFactoryImpl.kt

@@ -38,19 +38,13 @@ class TokenFactoryImpl : TokenFactory {
         }
     }
 
-    override fun createEofToken(position: FilePosition): Token {
-        return Eof("EOF", position)
-    }
+    override fun createEofToken(position: FilePosition) = Eof("EOF", position)
 
-    private fun isNumeric(firstCharacter: Char, text: String): Boolean {
-        return isDigit(firstCharacter) || isPrefixedNumeric(firstCharacter, text)
-    }
+    private fun isNumeric(firstCharacter: Char, text: String) =
+        isDigit(firstCharacter) || isPrefixedNumeric(firstCharacter, text)
 
-    private fun isPrefixedNumeric(firstCharacter: Char, text: String): Boolean {
-        return isNumberPrefix(firstCharacter) && isNextCharacterDigit(text)
-    }
+    private fun isPrefixedNumeric(firstCharacter: Char, text: String) =
+        isNumberPrefix(firstCharacter) && isNextCharacterDigit(text)
 
-    private fun isNextCharacterDigit(text: String): Boolean {
-        return text.length > 1 && isDigit(text[1])
-    }
+    private fun isNextCharacterDigit(text: String) = text.length > 1 && isDigit(text[1])
 }

src/test/kotlin/application/MainTest.kt

@@ -94,7 +94,7 @@ class MainTest : SymbolAndFunctionCleaner() {
 
         exit.expectSystemExitWithStatus(1)
         exit.checkAssertionAfterwards {
-            assertEquals(format("{0}{1}{2}\n", ANSI_PURPLE, expectedMessage, ANSI_RESET), systemErrLog())
+            assertEquals("$ANSI_PURPLE$expectedMessage$ANSI_RESET\n", systemErrLog())
             assertEquals("", systemOutLog())
         }
 
@@ -106,7 +106,7 @@ class MainTest : SymbolAndFunctionCleaner() {
         runInterpreterWithFile(FILE)
 
         assertEquals("", systemErrLog())
-        assertEquals(format("{0}{1}{2}\n\n", ANSI_GREEN, "RADISH", ANSI_RESET), systemOutLog())
+        assertEquals("${ANSI_GREEN}RADISH$ANSI_RESET\n\n", systemOutLog())
     }
 
     @Test

src/test/kotlin/interpreter/LispInterpreterTest.kt

@@ -11,7 +11,6 @@ import org.junit.Test
 import testutil.TestUtilities.createInputStreamFromString
 import java.io.ByteArrayOutputStream
 import java.io.PrintStream
-import java.text.MessageFormat.format
 import java.util.HashSet
 
 class LispInterpreterTest {
@@ -137,7 +136,7 @@ class LispInterpreterTest {
         LispInterpreterBuilder.setInput(createInputStreamFromString("'pickle"), "input")
         LispInterpreterBuilder.build().interpret()
 
-        assertEquals(format("{0}\n{1}\n{0}\n", PROMPT, "PICKLE"), outputStream.toString())
+        assertEquals("$PROMPT\nPICKLE\n$PROMPT\n", outputStream.toString())
         assertEquals("", errorOutputStream.toString())
     }
 

src/test/kotlin/token/TokenFactoryTest.kt

@@ -17,68 +17,66 @@ class TokenFactoryTest {
     private lateinit var tokenFactory: TokenFactory
     private lateinit var testPosition: FilePosition
 
+    private fun createToken(text: String) = tokenFactory.createToken(text, testPosition)
+
     @BeforeEach
     fun setUp() {
         tokenFactory = TokenFactoryImpl()
         testPosition = FilePosition("testFile", 0, 0)
     }
 
-    private fun createToken(text: String): Token {
-        return tokenFactory.createToken(text, testPosition)
-    }
-
     @Test
-    fun eofTokenCreation() {
+    fun `create EOF token`() {
         assertThat(tokenFactory.createEofToken(testPosition)).isInstanceOf(Eof::class.java)
     }
 
     @Test
-    fun leftParenthesisCreation() {
+    fun `create left parenthesis`() {
         assertThat(createToken("(")).isInstanceOf(LeftParenthesis::class.java)
     }
 
     @Test
-    fun rightParenthesisCreation() {
+    fun `create right parenthesis`() {
         assertThat(createToken(")")).isInstanceOf(RightParenthesis::class.java)
     }
 
     @Test
-    fun quoteMarkCreation() {
+    fun `create quote mark`() {
         assertThat(createToken("'")).isInstanceOf(QuoteMark::class.java)
     }
 
     @Test
-    fun numberCreation() {
+    fun `create number`() {
         assertThat(createToken("987")).isInstanceOf(Number::class.java)
     }
 
     @Test
-    fun prefixedNumberCreation() {
+    fun `create prefixed number`() {
         assertThat(createToken("-987")).isInstanceOf(Number::class.java)
     }
 
     @Test
-    fun identifierCreation() {
+    fun `create identifier`() {
         assertThat(createToken("identifier")).isInstanceOf(Identifier::class.java)
     }
 
     @Test
-    fun prefixedIdentifierCreation() {
+    fun `create prefixed identifier`() {
         assertThat(createToken("-identifier")).isInstanceOf(Identifier::class.java)
     }
 
     @Test
-    fun stringCreation() {
+    fun `create string`() {
         assertThat(createToken("\"string\"")).isInstanceOf(QuotedString::class.java)
     }
 
     @Test
-    fun emptyString_ThrowsException() {
+    fun `empty string throws exception`() {
         assertThrows(EmptyTokenTextException::class.java) { createToken("") }
     }
 
     @Test
-    fun emptyTokenTextException_ContainsCorrectAttributes() {
+    fun `EmptyTokenTextException is cool`() {
         try {
             createToken("")
         } catch (e: EmptyTokenTextException) {
@@ -88,22 +86,22 @@ class TokenFactoryTest {
     }
 
     @Test
-    fun badCharacter_ThrowsException() {
+    fun `bad character throws exception`() {
         assertThrows(BadCharacterException::class.java) { createToken("[abc]") }
     }
 
     @Test
-    fun backTickCreation() {
+    fun `create back tick`() {
         assertThat(createToken("`")).isInstanceOf(Backquote::class.java)
     }
 
     @Test
-    fun commaCreation() {
+    fun `create comma`() {
         assertThat(createToken(",")).isInstanceOf(Comma::class.java)
     }
 
     @Test
-    fun atSignCreation() {
+    fun `create at sign`() {
         assertThat(createToken("@")).isInstanceOf(AtSign::class.java)
     }
 }