Rule: NoSpaceBetweenParentheses

New rule forbids redundant spaces between parentheses. Fixes pinterest#223

ktlint-ruleset-standard/src/main/kotlin/com/github/shyiko/ktlint/ruleset/standard/NoSpaceBetweenParentheses.kt

@@ -0,0 +1,36 @@
+package com.github.shyiko.ktlint.ruleset.standard
+
+import com.github.shyiko.ktlint.core.Rule
+import org.jetbrains.kotlin.com.intellij.lang.ASTNode
+import org.jetbrains.kotlin.com.intellij.psi.PsiWhiteSpace
+import org.jetbrains.kotlin.lexer.KtTokens
+import org.jetbrains.kotlin.psi.psiUtil.siblings
+
+class NoSpaceBetweenParentheses : Rule("no-space-between-parentheses") {
+
+    override fun visit(node: ASTNode, autoCorrect: Boolean, emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> Unit) {
+        if (node.elementType == KtTokens.LPAR) {
+            val iterator = node.siblings().iterator()
+            var foundEnclosingPar = false
+            var hasSpaces = false
+            while (iterator.hasNext() && !foundEnclosingPar) {
+                val nextNode = iterator.next()
+                if (!hasSpaces && nextNode is PsiWhiteSpace) {
+                    hasSpaces = true
+                } else if (nextNode.elementType == KtTokens.RPAR) {
+                    foundEnclosingPar = true
+                } else {
+                    // the case when there are parameters or multiline declaration
+                    break
+                }
+            }
+            if (hasSpaces && foundEnclosingPar) {
+                emit(node.startOffset + 1, "Unexpected space between parentheses", true)
+                if (autoCorrect) {
+                    val enclosingPar = node.siblings().first { it.elementType == KtTokens.RPAR }
+                    node.treeParent.removeRange(node.siblings().first(), enclosingPar)
+                }
+            }
+        }
+    }
+}

ktlint-ruleset-standard/src/main/kotlin/com/github/shyiko/ktlint/ruleset/standard/StandardRuleSetProvider.kt

@@ -24,6 +24,7 @@ class StandardRuleSetProvider : RuleSetProvider {
         NoLineBreakBeforeAssignmentRule(),
         NoMultipleSpacesRule(),
         NoSemicolonsRule(),
+        NoSpaceBetweenParentheses(),
         NoTrailingSpacesRule(),
         NoUnitReturnRule(),
         NoUnusedImportsRule(),

ktlint-ruleset-standard/src/test/kotlin/com/github/shyiko/ktlint/ruleset/standard/NoSpaceBetweenParenthesesTest.kt

@@ -0,0 +1,40 @@
+package com.github.shyiko.ktlint.ruleset.standard
+
+import com.github.shyiko.ktlint.core.LintError
+import com.github.shyiko.ktlint.test.format
+import com.github.shyiko.ktlint.test.lint
+import org.assertj.core.api.Assertions.assertThat
+import org.testng.annotations.Test
+
+class NoSpaceBetweenParenthesesTest {
+    @Test
+    fun testFailWhenEncounterSpace() {
+        assertThat(NoSpaceBetweenParentheses().lint("fun main( ) {}"))
+            .isEqualTo(listOf(
+                LintError(1, 10, "no-space-between-parentheses", "Unexpected space between parentheses")
+            ))
+    }
+
+    @Test
+    fun testNoFailureWhenOnlyParentheses() {
+        assertThat(NoSpaceBetweenParentheses().lint("fun main() {}"))
+            .isEmpty()
+    }
+
+    @Test
+    fun testNoFailureWhenMultilineDeclaration() {
+        assertThat(NoSpaceBetweenParentheses().lint(
+            """
+                fun main(
+                  val a: String
+                ) {}
+             """
+        )).isEmpty()
+    }
+
+    @Test
+    fun testAutoFormat() {
+        assertThat(NoSpaceBetweenParentheses().format("fun main( ) {}"))
+            .isEqualTo("fun main() {}")
+    }
+}