From 4eabeca2aca772fc566565920c4df2f2fab1ea07 Mon Sep 17 00:00:00 2001
From: Victor <annimon119@gmail.com>
Date: Fri, 4 Jan 2019 23:40:22 +0200
Subject: [PATCH] =?UTF-8?q?=D0=A3=D0=BB=D1=83=D1=87=D1=88=D0=B5=D0=BD=20?=
 =?UTF-8?q?=D0=B2=D1=8B=D0=B2=D0=BE=D0=B4=20=D0=BE=D1=88=D0=B8=D0=B1=D0=BE?=
 =?UTF-8?q?=D0=BA?=
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---
 .../annimon/ownlang/lib/UserDefinedFunction.java |  6 ++++--
 .../ownlang/parser/ast/FunctionalExpression.java | 16 ++++++++++++----
 .../annimon/ownlang/parser/ast/UseStatement.java | 11 ++++++++---
 3 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/src/main/java/com/annimon/ownlang/lib/UserDefinedFunction.java b/src/main/java/com/annimon/ownlang/lib/UserDefinedFunction.java
index ab954c3..965be46 100644
--- a/src/main/java/com/annimon/ownlang/lib/UserDefinedFunction.java
+++ b/src/main/java/com/annimon/ownlang/lib/UserDefinedFunction.java
@@ -34,11 +34,13 @@ public final class UserDefinedFunction implements Function {
         final int size = values.length;
         final int requiredArgsCount = arguments.getRequiredArgumentsCount();
         if (size < requiredArgsCount) {
-            throw new ArgumentsMismatchException(String.format("Arguments count mismatch. %d < %d", size, requiredArgsCount));
+            throw new ArgumentsMismatchException(String.format(
+                    "Arguments count mismatch. Required %d, got %d", requiredArgsCount, size));
         }
         final int totalArgsCount = getArgsCount();
         if (size > totalArgsCount) {
-            throw new ArgumentsMismatchException(String.format("Arguments count mismatch. %d > %d", size, totalArgsCount));
+            throw new ArgumentsMismatchException(String.format(
+                    "Arguments count mismatch. Total %d, got %d", totalArgsCount, size));
         }
 
         try {
diff --git a/src/main/java/com/annimon/ownlang/parser/ast/FunctionalExpression.java b/src/main/java/com/annimon/ownlang/parser/ast/FunctionalExpression.java
index 672f3f1..103ca47 100644
--- a/src/main/java/com/annimon/ownlang/parser/ast/FunctionalExpression.java
+++ b/src/main/java/com/annimon/ownlang/parser/ast/FunctionalExpression.java
@@ -1,5 +1,7 @@
 package com.annimon.ownlang.parser.ast;
 
+import com.annimon.ownlang.exceptions.ArgumentsMismatchException;
+import com.annimon.ownlang.exceptions.TypeException;
 import com.annimon.ownlang.exceptions.VariableDoesNotExistsException;
 import com.annimon.ownlang.exceptions.UnknownFunctionException;
 import com.annimon.ownlang.lib.*;
@@ -40,9 +42,13 @@ public final class FunctionalExpression extends InterruptableNode implements Exp
         }
         final Function f = consumeFunction(functionExpr);
         CallStack.enter(functionExpr.toString(), f);
-        final Value result = f.execute(values);
-        CallStack.exit();
-        return result;
+        try {
+            return f.execute(values);
+        } catch (ArgumentsMismatchException | TypeException | VariableDoesNotExistsException ex) {
+            throw new RuntimeException(ex.getMessage() + " in function " + functionExpr, ex);
+        } finally {
+            CallStack.exit();
+        }
     }
     
     private Function consumeFunction(Expression expr) {
@@ -58,7 +64,9 @@ public final class FunctionalExpression extends InterruptableNode implements Exp
     }
     
     private Function getFunction(String key) {
-        if (Functions.isExists(key)) return Functions.get(key);
+        if (Functions.isExists(key)) {
+            return Functions.get(key);
+        }
         if (Variables.isExists(key)) {
             final Value variable = Variables.get(key);
             if (variable.type() == Types.FUNCTION) {
diff --git a/src/main/java/com/annimon/ownlang/parser/ast/UseStatement.java b/src/main/java/com/annimon/ownlang/parser/ast/UseStatement.java
index 568b63b..087f03e 100644
--- a/src/main/java/com/annimon/ownlang/parser/ast/UseStatement.java
+++ b/src/main/java/com/annimon/ownlang/parser/ast/UseStatement.java
@@ -36,7 +36,7 @@ public final class UseStatement extends InterruptableNode implements Statement {
                 loadModule(value.asString());
                 break;
             default:
-                throw new TypeException("Array or string required");
+                throw typeException(value);
         }
     }
 
@@ -45,7 +45,7 @@ public final class UseStatement extends InterruptableNode implements Statement {
             final Module module = (Module) Class.forName(String.format(PACKAGE, name, name)).newInstance();
             module.init();
         } catch (Exception ex) {
-            throw new RuntimeException(ex);
+            throw new RuntimeException("Unable to load module " + name, ex);
         }
     }
 
@@ -61,10 +61,15 @@ public final class UseStatement extends InterruptableNode implements Statement {
                 loadConstants(value.asString());
                 break;
             default:
-                throw new TypeException("Array or string required");
+                throw typeException(value);
         }
     }
 
+    private TypeException typeException(Value value) {
+        return new TypeException("Array or string required in 'use' statement, " +
+                "got " + Types.typeToString(value.type()) + " " + value);
+    }
+
     private void loadConstants(String moduleName) {
         try {
             final Class<?> moduleClass = Class.forName(String.format(PACKAGE, moduleName, moduleName));