[#753] Add transformer to correct the variable names. Improve error handling in DMN environment factory.

Author: opatrascoiu

dmn-core/src/main/java/com/gs/dmn/error/ErrorFactory.java

@@ -12,10 +12,7 @@
  */
 package com.gs.dmn.error;
 
-import com.gs.dmn.ast.TDMNElement;
-import com.gs.dmn.ast.TDefinitions;
-import com.gs.dmn.ast.TExpression;
-import com.gs.dmn.ast.TNamedElement;
+import com.gs.dmn.ast.*;
 import com.gs.dmn.el.analysis.semantics.type.Type;
 import com.gs.dmn.el.analysis.syntax.ast.expression.Expression;
 import org.apache.commons.lang3.StringUtils;
@@ -65,7 +62,13 @@ private static String makeExpressionErrorMessage(TDefinitions definitions, TDMNE
     }
 
     private static String expressionDescription(Object expression) {
-        return expression == null ? null : expression.toString();
+        if (expression == null) {
+            return null;
+        } else if (expression instanceof TLiteralExpression) {
+            return ((TLiteralExpression) expression).getText();
+        } else {
+            return expression.toString();
+        }
     }
 
     public static String makeErrorMessage(String location, String errorMessage) {

dmn-core/src/main/java/com/gs/dmn/transformation/basic/StandardDMNEnvironmentFactory.java

@@ -550,18 +550,19 @@ public Type toFEELType(TDefinitions model, QualifiedName typeRef) {
     private Type toFEELTypeNoCache(TDefinitions model, QualifiedName typeRef) {
         // Lookup item definitions
         if (model != null) {
-        TItemDefinition itemDefinition = this.dmnModelRepository.lookupItemDefinition(model, typeRef);
-        if (itemDefinition != null) {
-            return toFEELType(itemDefinition);
-        }
+            TItemDefinition itemDefinition = this.dmnModelRepository.lookupItemDefinition(model, typeRef);
+            if (itemDefinition != null) {
+                return toFEELType(itemDefinition);
+            }
         }
 
         // Lookup primitive types
         Type primitiveType = lookupPrimitiveType(typeRef);
         if (primitiveType != null) {
             return primitiveType;
         }
-        throw new SemanticError(String.format("Cannot map type '%s' to FEEL", typeRef));
+
+        throw new SemanticError(ErrorFactory.makeDMNErrorMessage(model, null, String.format("Cannot map type '%s' to FEEL", typeRef)));
     }
 
     @Override
@@ -821,7 +822,7 @@ private Environment makeEnvironmentNoCache(TDRGElement element) {
 
             return elementEnvironment;
         } catch (Exception e) {
-            throw new SemanticError(ErrorFactory.makeDMNErrorMessage(definitions, element, e.getMessage()), e);
+            throw new SemanticError(ErrorFactory.makeDMNErrorMessage(definitions, element, "Cannot create environment due to semantic errors"), e);
         }
     }