Introduce basic error handling

api/src/main/kotlin/io/smnp/callable/function/Function.kt

@@ -2,7 +2,6 @@ package io.smnp.callable.function
 
 import io.smnp.environment.Environment
 import io.smnp.error.FunctionInvocationException
-import io.smnp.error.RuntimeException
 import io.smnp.type.model.Value
 import io.smnp.type.module.Module
 
@@ -25,7 +24,7 @@ abstract class Function(val name: String) {
         val (definition, args) = definitions
             .map { Pair(it, it.signature.parse(arguments.toList())) }
             .firstOrNull { (_, args) -> args.signatureMatched }
-            ?: throw FunctionInvocationException(this, arguments)
+            ?: throw FunctionInvocationException(this, arguments, environment)
 
         return definition.body(environment, args.arguments)
     }

api/src/main/kotlin/io/smnp/callable/method/Method.kt

@@ -2,7 +2,6 @@ package io.smnp.callable.method
 
 import io.smnp.environment.Environment
 import io.smnp.error.MethodInvocationException
-import io.smnp.error.RuntimeException
 import io.smnp.type.matcher.Matcher
 import io.smnp.type.model.Value
 import io.smnp.type.module.Module
@@ -28,7 +27,7 @@ abstract class Method(val typeMatcher: Matcher, val name: String) {
         val (definition, args) = definitions
             .map { Pair(it, it.signature.parse(arguments.toList())) }
             .firstOrNull { (_, args) -> args.signatureMatched }
-            ?: throw MethodInvocationException(this, obj, arguments)
+            ?: throw MethodInvocationException(this, obj, arguments, environment)
 
         return definition.body(environment, obj, args.arguments)
     }

api/src/main/kotlin/io/smnp/environment/Environment.kt

@@ -11,6 +11,7 @@ interface Environment {
    fun invokeFunction(name: String, arguments: List<Value>): Value
    fun invokeMethod(obj: Value, name: String, arguments: List<Value>): Value
    fun printCallStack()
+   fun stackTrace(): String
    fun defineFunction(function: Function)
    fun defineMethod(method: Method)
    fun pushScope(scope: MutableMap<String, Value> = mutableMapOf())

api/src/main/kotlin/io/smnp/error/CustomException.kt

@@ -1,3 +1,3 @@
 package io.smnp.error
 
-class CustomException(message: String?) : Exception(message)
+class CustomException(message: String?) : SmnpException("Error", message)

api/src/main/kotlin/io/smnp/error/EnvironmentException.kt

@@ -0,0 +1,8 @@
+package io.smnp.error
+
+import io.smnp.environment.Environment
+
+class EnvironmentException(exception: SmnpException, val environment: Environment) : SmnpException(
+   exception.friendlyName,
+   "${exception.message}\n\nStack trace:\n${environment.stackTrace()}"
+)

api/src/main/kotlin/io/smnp/error/EvaluationException.kt

@@ -0,0 +1,3 @@
+package io.smnp.error
+
+class EvaluationException(message: String?) : SmnpException("Runtime error", message)

api/src/main/kotlin/io/smnp/error/FunctionInvocationException.kt

@@ -2,8 +2,14 @@ package io.smnp.error
 
 import io.smnp.callable.function.Function
 import io.smnp.callable.signature.ActualSignatureFormatter.format
+import io.smnp.environment.Environment
 import io.smnp.type.model.Value
 
-class FunctionInvocationException(private val function: Function, private val passedArguments: Array<out Value>) : Exception() {
-    override fun toString() = "Invalid signature: ${function.name}${format(passedArguments)}\nAllowed signatures:\n${function.signature}"
-}
+class FunctionInvocationException(
+   function: Function,
+   passedArguments: Array<out Value>,
+   val environment: Environment
+) : SmnpException(
+   "Function invocation error",
+   "Invalid signature: ${function.name}${format(passedArguments)}\nAllowed signatures:\n${function.signature}"
+)

api/src/main/kotlin/io/smnp/error/MethodInvocationException.kt

@@ -2,8 +2,15 @@ package io.smnp.error
 
 import io.smnp.callable.method.Method
 import io.smnp.callable.signature.ActualSignatureFormatter.format
+import io.smnp.environment.Environment
 import io.smnp.type.model.Value
 
-class MethodInvocationException(private val method: Method, private val obj: Value, private val passedArguments: Array<out Value>) : Exception() {
-    override fun toString() = "Invalid signature: $obj.${method.name}${format(passedArguments)}\nAllowed signatures:\n${method.signature}"
-}
+class MethodInvocationException(
+   method: Method,
+   obj: Value,
+   passedArguments: Array<out Value>,
+   val environment: Environment
+) : SmnpException(
+   "Method invocation error",
+   "Invalid signature: $obj.${method.name}${format(passedArguments)}\nAllowed signatures:\n${method.signature}"
+)

api/src/main/kotlin/io/smnp/error/RuntimeException.kt

@@ -1,3 +0,0 @@
-package io.smnp.error
-
-class RuntimeException(message: String?) : Exception(message)

api/src/main/kotlin/io/smnp/error/SmnpException.kt

@@ -0,0 +1,3 @@
+package io.smnp.error
+
+abstract class SmnpException(val friendlyName: String, message: String? = null) : Exception(message)

api/src/main/kotlin/io/smnp/runtime/model/CallStack.kt

@@ -21,4 +21,6 @@ class CallStack {
     fun pretty() {
         items.asReversed().forEachIndexed { index, item -> println("[${items.size - index - 1}] $item") }
     }
+
+    fun stackTrace() = items.asReversed().mapIndexed { index, item -> "[${items.size - index - 1}] $item" }.joinToString("\n")
 }

api/src/main/kotlin/io/smnp/runtime/model/CallStackFrame.kt

@@ -2,6 +2,7 @@ package io.smnp.runtime.model
 
 import io.smnp.callable.signature.ActualSignatureFormatter
 import io.smnp.collection.Stack
+import io.smnp.error.EvaluationException
 import io.smnp.type.model.Value
 import io.smnp.type.module.Module
 
@@ -24,7 +25,7 @@ data class CallStackFrame(
     }
 
     fun getVariable(name: String): Value {
-        return scopes.lastOrNull { it.containsKey(name) }?.get(name) ?: throw RuntimeException("Undefined variable `$name`")
+        return scopes.lastOrNull { it.containsKey(name) }?.get(name) ?: throw EvaluationException("Undefined variable `$name`")
     }
 
     fun prettyScope() {