diff --git a/.idea/gradle.xml b/.idea/gradle.xml
index a7f8d22..7827ecc 100644
--- a/.idea/gradle.xml
+++ b/.idea/gradle.xml
@@ -3,11 +3,23 @@
   <component name="GradleSettings">
     <option name="linkedExternalProjectsSettings">
       <GradleProjectSettings>
+        <compositeConfiguration>
+          <compositeBuild compositeDefinitionSource="SCRIPT">
+            <builds>
+              <build path="$PROJECT_DIR$/buildSrc" name="buildSrc">
+                <projects>
+                  <project path="$PROJECT_DIR$/buildSrc" />
+                </projects>
+              </build>
+            </builds>
+          </compositeBuild>
+        </compositeConfiguration>
         <option name="externalProjectPath" value="$PROJECT_DIR$" />
         <option name="gradleHome" value="" />
         <option name="modules">
           <set>
             <option value="$PROJECT_DIR$" />
+            <option value="$PROJECT_DIR$/buildSrc" />
             <option value="$PROJECT_DIR$/collect" />
             <option value="$PROJECT_DIR$/core" />
             <option value="$PROJECT_DIR$/guava" />
diff --git a/buildSrc/build.gradle.kts b/buildSrc/build.gradle.kts
new file mode 100644
index 0000000..48ce654
--- /dev/null
+++ b/buildSrc/build.gradle.kts
@@ -0,0 +1,8 @@
+
+plugins {
+	kotlin("jvm") version "1.8.0"
+}
+
+repositories {
+	mavenCentral()
+}
diff --git a/collect/build.gradle.kts b/collect/build.gradle.kts
index 2aa93e5..739dbc4 100644
--- a/collect/build.gradle.kts
+++ b/collect/build.gradle.kts
@@ -5,6 +5,7 @@ plugins {
 
 val collectVersion: String by project
 val projectGroup: String by project
+val specifyKotlinAsDependency: String by project
 
 group = projectGroup
 version = collectVersion
@@ -32,7 +33,7 @@ publishing {
 
             pom {
                 dependencies {
-                    implementation(kotlin("stdlib"))
+                    if (specifyKotlinAsDependency.toBoolean()) implementation(kotlin("stdlib"))
                 }
             }
         }
diff --git a/core/build.gradle.kts b/core/build.gradle.kts
index 676208e..652473f 100644
--- a/core/build.gradle.kts
+++ b/core/build.gradle.kts
@@ -6,6 +6,7 @@ plugins {
 
 val coreVersion: String by project
 val projectGroup: String by project
+val specifyKotlinAsDependency: String by project
 
 group = projectGroup
 version = coreVersion
@@ -33,7 +34,7 @@ publishing {
 
             pom {
                 dependencies {
-                    implementation(kotlin("stdlib"))
+                    if (specifyKotlinAsDependency.toBoolean()) implementation(kotlin("stdlib"))
                 }
             }
         }
diff --git a/gradle.properties b/gradle.properties
index 282f804..a2884da 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -1,6 +1,8 @@
 
 kotlin.code.style=official
 
+specifyKotlinAsDependency=false
+
 projectGroup=ru.dbotthepony.kommons
 
 guavaDepVersion=33.0.0
diff --git a/guava/build.gradle.kts b/guava/build.gradle.kts
index 0b83e59..bbaf06c 100644
--- a/guava/build.gradle.kts
+++ b/guava/build.gradle.kts
@@ -6,6 +6,7 @@ plugins {
 val guavaVersion: String by project
 val guavaDepVersion: String by project
 val projectGroup: String by project
+val specifyKotlinAsDependency: String by project
 
 group = projectGroup
 version = guavaVersion
@@ -35,7 +36,8 @@ publishing {
 
             pom {
                 dependencies {
-                    implementation(kotlin("stdlib"))
+                    if (specifyKotlinAsDependency.toBoolean()) implementation(kotlin("stdlib"))
+                    implementation("com.google.guava:guava:[28,)")
                 }
             }
         }
diff --git a/io-math/build.gradle.kts b/io-math/build.gradle.kts
index fa3b946..4cf82b4 100644
--- a/io-math/build.gradle.kts
+++ b/io-math/build.gradle.kts
@@ -5,6 +5,7 @@ plugins {
 
 val kommonsVersion: String by project
 val projectGroup: String by project
+val specifyKotlinAsDependency: String by project
 
 group = projectGroup
 version = kommonsVersion
@@ -34,7 +35,7 @@ publishing {
 
             pom {
                 dependencies {
-                    implementation(kotlin("stdlib"))
+                    if (specifyKotlinAsDependency.toBoolean()) implementation(kotlin("stdlib"))
                     implementation(project(":io"))
                     implementation(project(":math"))
                 }
diff --git a/io/build.gradle.kts b/io/build.gradle.kts
index ff3c321..44fc8d9 100644
--- a/io/build.gradle.kts
+++ b/io/build.gradle.kts
@@ -5,6 +5,7 @@ plugins {
 
 val ioVersion: String by project
 val projectGroup: String by project
+val specifyKotlinAsDependency: String by project
 
 group = projectGroup
 version = ioVersion
@@ -33,7 +34,7 @@ publishing {
 
             pom {
                 dependencies {
-                    implementation(kotlin("stdlib"))
+                    if (specifyKotlinAsDependency.toBoolean()) implementation(kotlin("stdlib"))
                     implementation(project(":core"))
                 }
             }
diff --git a/math/build.gradle.kts b/math/build.gradle.kts
index 2d363f8..52c5a2f 100644
--- a/math/build.gradle.kts
+++ b/math/build.gradle.kts
@@ -5,6 +5,7 @@ plugins {
 
 val mathVersion: String by project
 val projectGroup: String by project
+val specifyKotlinAsDependency: String by project
 
 group = projectGroup
 version = mathVersion
@@ -32,7 +33,7 @@ publishing {
 
             pom {
                 dependencies {
-                    implementation(kotlin("stdlib"))
+                    if (specifyKotlinAsDependency.toBoolean()) implementation(kotlin("stdlib"))
                 }
             }
         }
diff --git a/math/src/main/kotlin/ru/dbotthepony/kommons/math/Decimal.kt b/math/src/main/kotlin/ru/dbotthepony/kommons/math/Decimal.kt
index bcad465..9584db2 100644
--- a/math/src/main/kotlin/ru/dbotthepony/kommons/math/Decimal.kt
+++ b/math/src/main/kotlin/ru/dbotthepony/kommons/math/Decimal.kt
@@ -104,6 +104,10 @@ sealed class Decimal : Number(), Comparable<Decimal> {
 	// "de-virtualize" generic method
 	abstract override fun compareTo(other: Decimal): Int
 
+	override fun toChar(): Char {
+		return toInt().toChar()
+	}
+
 	abstract operator fun unaryMinus(): Decimal
 	operator fun unaryPlus() = this