uCalc API Version: 2.1.3-preview.2 Released: 6/16/2026

Warning

uCalc API Preview Release Notice:The documentation describes the intended behavior of the API. The current preview build contains incomplete features, unoptimized performance, and is subject to breaking changes.

Error = [ErrorInfo]

Property

Product: 

Fast Math Parser

Class: 

uCalcBase

ErrorInfo object with details like error location, message, etc.

Remarks

Examples

Adding an error handler callback
				
					using uCalcSoftware;

var uc = new uCalc();

static void MyErrorHandler(Handle_uCalc h) {
   var uc = new uCalc(h);
   Console.WriteLine("An error has occurred!");
   Console.WriteLine($"Error #: {(int)uc.Error.Code}");
   Console.WriteLine($"Error Message: {uc.Error.Message}");
   Console.WriteLine($"Error Symbol: {uc.Error.Symbol}");
   Console.WriteLine($"Error Location: {uc.Error.Location}");
   Console.WriteLine($"Error Expression: {uc.Error.Expression}");
}


uc.Error.AddHandler(MyErrorHandler);
Console.WriteLine(uc.EvalStr("123+"));
Console.WriteLine("");

uc.Error.TrapOnDivideByZero = true;
Console.WriteLine(uc.EvalStr("5/0"));
				
			
An error has occurred!
Error #: 257
Error Message: Syntax error
Error Symbol: +
Error Location: 3
Error Expression: 123+
Syntax error

An error has occurred!
Error #: 8
Error Message: Division by 0
Error Symbol: 
Error Location: 0
Error Expression: 
Division by 0
				
					#include <iostream>
#include "uCalc.h"

using namespace std;
using namespace uCalcSoftware;

void ucalc_call MyErrorHandler(Handle_uCalc h) {
   auto uc = uCalc(h);
   cout << "An error has occurred!" << endl;
   cout << "Error #: " << (int)uc.Error().Code() << endl;
   cout << "Error Message: " << uc.Error().Message() << endl;
   cout << "Error Symbol: " << uc.Error().Symbol() << endl;
   cout << "Error Location: " << uc.Error().Location() << endl;
   cout << "Error Expression: " << uc.Error().Expression() << endl;
}

int main() {
   uCalc uc;
   uc.Error().AddHandler(MyErrorHandler);
   cout << uc.EvalStr("123+") << endl;
   cout << "" << endl;

   uc.Error().TrapOnDivideByZero(true);
   cout << uc.EvalStr("5/0") << endl;
}
				
			
An error has occurred!
Error #: 257
Error Message: Syntax error
Error Symbol: +
Error Location: 3
Error Expression: 123+
Syntax error

An error has occurred!
Error #: 8
Error Message: Division by 0
Error Symbol: 
Error Location: 0
Error Expression: 
Division by 0
				
					Imports System
Imports uCalcSoftware
Public Module Program
   
   Public Sub MyErrorHandler(ByVal h As Handle_uCalc)
      Dim uc As New uCalc(h)
      Console.WriteLine("An error has occurred!")
      Console.WriteLine($"Error #: {CInt(uc.Error.Code)}")
      Console.WriteLine($"Error Message: {uc.Error.Message}")
      Console.WriteLine($"Error Symbol: {uc.Error.Symbol}")
      Console.WriteLine($"Error Location: {uc.Error.Location}")
      Console.WriteLine($"Error Expression: {uc.Error.Expression}")
   End Sub
   
   Public Sub Main()
      Dim uc As New uCalc()
      uc.Error.AddHandler(AddressOf MyErrorHandler)
      Console.WriteLine(uc.EvalStr("123+"))
      Console.WriteLine("")
      
      uc.Error.TrapOnDivideByZero = true
      Console.WriteLine(uc.EvalStr("5/0"))
   End Sub
End Module
				
			
An error has occurred!
Error #: 257
Error Message: Syntax error
Error Symbol: +
Error Location: 3
Error Expression: 123+
Syntax error

An error has occurred!
Error #: 8
Error Message: Division by 0
Error Symbol: 
Error Location: 0
Error Expression: 
Division by 0
Internal Test: Verifies that the error code is correctly cleared after a successful operation.
				
					using uCalcSoftware;

var uc = new uCalc();
// Trigger an error and check the code
uc.EvalStr("1+");
Console.WriteLine($"1. Error code after failure: {(int)uc.Error.Code}");

// A successful evaluation should clear the error code
uc.EvalStr("1+1");
Console.WriteLine($"2. Error code after success: {(int)uc.Error.Code}");

// Trigger a different type of error
uc.Error.TrapOnDivideByZero = true;
uc.EvalStr("1/0");
Console.WriteLine($"3. Error code after new failure: {(int)uc.Error.Code}");

// A successful definition should also clear the error code
uc.DefineVariable("x=5");
Console.WriteLine($"4. Error code after successful definition: {(int)uc.Error.Code}");
				
			
1. Error code after failure: 257
2. Error code after success: 0
3. Error code after new failure: 8
4. Error code after successful definition: 0
				
					#include <iostream>
#include "uCalc.h"

using namespace std;
using namespace uCalcSoftware;

int main() {
   uCalc uc;
   // Trigger an error and check the code
   uc.EvalStr("1+");
   cout << "1. Error code after failure: " << (int)uc.Error().Code() << endl;

   // A successful evaluation should clear the error code
   uc.EvalStr("1+1");
   cout << "2. Error code after success: " << (int)uc.Error().Code() << endl;

   // Trigger a different type of error
   uc.Error().TrapOnDivideByZero(true);
   uc.EvalStr("1/0");
   cout << "3. Error code after new failure: " << (int)uc.Error().Code() << endl;

   // A successful definition should also clear the error code
   uc.DefineVariable("x=5");
   cout << "4. Error code after successful definition: " << (int)uc.Error().Code() << endl;
}
				
			
1. Error code after failure: 257
2. Error code after success: 0
3. Error code after new failure: 8
4. Error code after successful definition: 0
				
					Imports System
Imports uCalcSoftware
Public Module Program
   Public Sub Main()
      Dim uc As New uCalc()
      '// Trigger an error and check the code
      uc.EvalStr("1+")
      Console.WriteLine($"1. Error code after failure: {uc.Error.Code.ToString("D")}")
      
      '// A successful evaluation should clear the error code
      uc.EvalStr("1+1")
      Console.WriteLine($"2. Error code after success: {uc.Error.Code.ToString("D")}")
      
      '// Trigger a different type of error
      uc.Error.TrapOnDivideByZero = true
      uc.EvalStr("1/0")
      Console.WriteLine($"3. Error code after new failure: {uc.Error.Code.ToString("D")}")
      
      '// A successful definition should also clear the error code
      uc.DefineVariable("x=5")
      Console.WriteLine($"4. Error code after successful definition: {uc.Error.Code.ToString("D")}")
   End Sub
End Module
				
			
1. Error code after failure: 257
2. Error code after success: 0
3. Error code after new failure: 8
4. Error code after successful definition: 0
Creating an error handler that automatically defines variables on the fly by checking for an 'Undefined Identifier' error.
				
					using uCalcSoftware;

var uc = new uCalc();

static void AutoDefineHandler(Handle_uCalc h) {
   var uc = new uCalc(h);
   // Check if the error is specifically an undefined identifier
   if (uc.Error.Code == ErrorCode.Undefined_Identifier) {
      // If so, define the missing variable and instruct uCalc to resume
      Console.WriteLine($"Auto-defining variable: '{uc.Error.Symbol}'");
      uc.DefineVariable(uc.Error.Symbol);
      uc.Error.Response = ErrorHandlerResponse.Resume;
   }
}


uc.Error.AddHandler(AutoDefineHandler);

// 'x' doesn't exist, but the handler will intercept the error and create it.
var Result = uc.EvalStr("x = 10; x * 5");
Console.WriteLine($"Result: {Result}");
				
			
Auto-defining variable: 'x'
Result: 50
				
					#include <iostream>
#include "uCalc.h"

using namespace std;
using namespace uCalcSoftware;

void ucalc_call AutoDefineHandler(Handle_uCalc h) {
   auto uc = uCalc(h);
   // Check if the error is specifically an undefined identifier
   if (uc.Error().Code() == ErrorCode::Undefined_Identifier) {
      // If so, define the missing variable and instruct uCalc to resume
      cout << "Auto-defining variable: '" << uc.Error().Symbol() << "'" << endl;
      uc.DefineVariable(uc.Error().Symbol());
      uc.Error().Response(ErrorHandlerResponse::Resume);
   }
}

int main() {
   uCalc uc;
   uc.Error().AddHandler(AutoDefineHandler);

   // 'x' doesn't exist, but the handler will intercept the error and create it.
   auto Result = uc.EvalStr("x = 10; x * 5");
   cout << "Result: " << Result << endl;
}
				
			
Auto-defining variable: 'x'
Result: 50
				
					Imports System
Imports uCalcSoftware
Public Module Program
   
   Public Sub AutoDefineHandler(ByVal h As Handle_uCalc)
      Dim uc As New uCalc(h)
      '// Check if the error is specifically an undefined identifier
      If uc.Error.Code = ErrorCode.Undefined_Identifier Then
         '// If so, define the missing variable and instruct uCalc to resume
         Console.WriteLine($"Auto-defining variable: '{uc.Error.Symbol}'")
         uc.DefineVariable(uc.Error.Symbol)
         uc.Error.Response = ErrorHandlerResponse.Resume
      End If
   End Sub
   
   Public Sub Main()
      Dim uc As New uCalc()
      uc.Error.AddHandler(AddressOf AutoDefineHandler)
      
      '// 'x' doesn't exist, but the handler will intercept the error and create it.
      Dim Result = uc.EvalStr("x = 10; x * 5")
      Console.WriteLine($"Result: {Result}")
   End Sub
End Module
				
			
Auto-defining variable: 'x'
Result: 50
Checking the error code for a simple syntax error using a callback.
				
					using uCalcSoftware;

var uc = new uCalc();

static void MyHandler(Handle_uCalc h) {
   var uc = new uCalc(h);
   // Retrieve the error code as an integer for display
   int code = (int)uc.Error.Code;
   Console.WriteLine($"Caught Error Code: {code}");

   // Compare the error code against the ErrorCode enum for logic
   if (uc.Error.Code == ErrorCode.Syntax_Error) {
      Console.WriteLine("This was a syntax error.");
   }
}


// Register the error handler
uc.Error.AddHandler(MyHandler);

// Intentionally cause a syntax error, which will trigger the handler
Console.WriteLine(uc.EvalStr("5 *"));
				
			
Caught Error Code: 257
This was a syntax error.
Syntax error
				
					#include <iostream>
#include "uCalc.h"

using namespace std;
using namespace uCalcSoftware;

void ucalc_call MyHandler(Handle_uCalc h) {
   auto uc = uCalc(h);
   // Retrieve the error code as an integer for display
   int code = (int)uc.Error().Code();
   cout << "Caught Error Code: " << code << endl;

   // Compare the error code against the ErrorCode enum for logic
   if (uc.Error().Code() == ErrorCode::Syntax_Error) {
      cout << "This was a syntax error." << endl;
   }
}

int main() {
   uCalc uc;
   // Register the error handler
   uc.Error().AddHandler(MyHandler);

   // Intentionally cause a syntax error, which will trigger the handler
   cout << uc.EvalStr("5 *") << endl;
}
				
			
Caught Error Code: 257
This was a syntax error.
Syntax error
				
					Imports System
Imports uCalcSoftware
Public Module Program
   
   Public Sub MyHandler(ByVal h As Handle_uCalc)
      Dim uc As New uCalc(h)
      '// Retrieve the error code as an integer for display
      Dim code As Integer = uc.Error.Code
      Console.WriteLine($"Caught Error Code: {code}")
      
      '// Compare the error code against the ErrorCode enum for logic
      If uc.Error.Code = ErrorCode.Syntax_Error Then
         Console.WriteLine("This was a syntax error.")
      End If
   End Sub
   
   Public Sub Main()
      Dim uc As New uCalc()
      '// Register the error handler
      uc.Error.AddHandler(AddressOf MyHandler)
      
      '// Intentionally cause a syntax error, which will trigger the handler
      Console.WriteLine(uc.EvalStr("5 *"))
   End Sub
End Module
				
			
Caught Error Code: 257
This was a syntax error.
Syntax error
An internal test to confirm that ErrorExpression returns an empty string for an error triggered manually by a user function during evaluation.
				
					using uCalcSoftware;

var uc = new uCalc();

static void MyFunc(uCalc.Callback cb) {
   // This error occurs during evaluation, not parsing.
   cb.Error.Raise("Manual evaluation failure!");
}

static void MyHandler(Handle_uCalc h) {
   var uc = new uCalc(h);
   Console.WriteLine($"Handler triggered for error: {uc.Error.Message}");
   Console.WriteLine($"ErrorExpression() returned: '{uc.Error.Expression}'");
   Console.WriteLine($"Is expression empty? {uc.Error.Expression == ""}");
}


uc.DefineFunction("MyFunc()", MyFunc);
uc.Error.AddHandler(MyHandler);

// The expression 'MyFunc()' itself is valid syntactically.
Console.WriteLine(uc.EvalStr("MyFunc()"));
				
			
Handler triggered for error: Manual evaluation failure!
ErrorExpression() returned: ''
Is expression empty? True
Manual evaluation failure!
				
					#include <iostream>
#include "uCalc.h"

using namespace std;
using namespace uCalcSoftware;

#define tf(IsTrue) ((IsTrue) ? "True" : "False")

void ucalc_call MyFunc(uCalcBase::Callback cb) {
   // This error occurs during evaluation, not parsing.
   cb.Error().Raise("Manual evaluation failure!");
}

void ucalc_call MyHandler(Handle_uCalc h) {
   auto uc = uCalc(h);
   cout << "Handler triggered for error: " << uc.Error().Message() << endl;
   cout << "ErrorExpression() returned: '" << uc.Error().Expression() << "'" << endl;
   cout << "Is expression empty? " << tf(uc.Error().Expression() == "") << endl;
}

int main() {
   uCalc uc;
   uc.DefineFunction("MyFunc()", MyFunc);
   uc.Error().AddHandler(MyHandler);

   // The expression 'MyFunc()' itself is valid syntactically.
   cout << uc.EvalStr("MyFunc()") << endl;
}
				
			
Handler triggered for error: Manual evaluation failure!
ErrorExpression() returned: ''
Is expression empty? True
Manual evaluation failure!
				
					Imports System
Imports uCalcSoftware
Public Module Program
   
   Public Sub MyFunc(ByVal cb As uCalc.Callback)
      '// This error occurs during evaluation, not parsing.
      cb.Error.Raise("Manual evaluation failure!")
   End Sub
   
   Public Sub MyHandler(ByVal h As Handle_uCalc)
      Dim uc As New uCalc(h)
      Console.WriteLine($"Handler triggered for error: {uc.Error.Message}")
      Console.WriteLine($"ErrorExpression() returned: '{uc.Error.Expression}'")
      Console.WriteLine($"Is expression empty? {uc.Error.Expression = ""}")
   End Sub
   
   Public Sub Main()
      Dim uc As New uCalc()
      uc.DefineFunction("MyFunc()", AddressOf MyFunc)
      uc.Error.AddHandler(AddressOf MyHandler)
      
      '// The expression 'MyFunc()' itself is valid syntactically.
      Console.WriteLine(uc.EvalStr("MyFunc()"))
   End Sub
End Module
				
			
Handler triggered for error: Manual evaluation failure!
ErrorExpression() returned: ''
Is expression empty? True
Manual evaluation failure!
Capturing both parsing-stage and evaluation-stage errors to see how ErrorLocation behaves differently.
				
					using uCalcSoftware;

var uc = new uCalc();

static void MyErrorHandler(Handle_uCalc h) {
   var uc = new uCalc(h);
   Console.WriteLine("--- Error Captured ---");
   Console.WriteLine($"Message: {uc.Error.Message}");
   Console.WriteLine($"Symbol: '{uc.Error.Symbol}'");
   Console.WriteLine($"Location: {uc.Error.Location}");
   Console.WriteLine($"Expression: '{uc.Error.Expression}'");
}


uc.Error.AddHandler(MyErrorHandler);

Console.WriteLine("Demonstrating a PARSING error:");
uc.EvalStr("123//456");

Console.WriteLine("");
Console.WriteLine("Demonstrating an EVALUATION error:");
uc.Error.TrapOnDivideByZero = true;
uc.EvalStr("5/0");
				
			
Demonstrating a PARSING error:
--- Error Captured ---
Message: Syntax error
Symbol: '/'
Location: 3
Expression: '123//456'

Demonstrating an EVALUATION error:
--- Error Captured ---
Message: Division by 0
Symbol: ''
Location: 0
Expression: ''
				
					#include <iostream>
#include "uCalc.h"

using namespace std;
using namespace uCalcSoftware;

void ucalc_call MyErrorHandler(Handle_uCalc h) {
   auto uc = uCalc(h);
   cout << "--- Error Captured ---" << endl;
   cout << "Message: " << uc.Error().Message() << endl;
   cout << "Symbol: '" << uc.Error().Symbol() << "'" << endl;
   cout << "Location: " << uc.Error().Location() << endl;
   cout << "Expression: '" << uc.Error().Expression() << "'" << endl;
}

int main() {
   uCalc uc;
   uc.Error().AddHandler(MyErrorHandler);

   cout << "Demonstrating a PARSING error:" << endl;
   uc.EvalStr("123//456");

   cout << "" << endl;
   cout << "Demonstrating an EVALUATION error:" << endl;
   uc.Error().TrapOnDivideByZero(true);
   uc.EvalStr("5/0");
}
				
			
Demonstrating a PARSING error:
--- Error Captured ---
Message: Syntax error
Symbol: '/'
Location: 3
Expression: '123//456'

Demonstrating an EVALUATION error:
--- Error Captured ---
Message: Division by 0
Symbol: ''
Location: 0
Expression: ''
				
					Imports System
Imports uCalcSoftware
Public Module Program
   
   Public Sub MyErrorHandler(ByVal h As Handle_uCalc)
      Dim uc As New uCalc(h)
      Console.WriteLine("--- Error Captured ---")
      Console.WriteLine($"Message: {uc.Error.Message}")
      Console.WriteLine($"Symbol: '{uc.Error.Symbol}'")
      Console.WriteLine($"Location: {uc.Error.Location}")
      Console.WriteLine($"Expression: '{uc.Error.Expression}'")
   End Sub
   
   Public Sub Main()
      Dim uc As New uCalc()
      uc.Error.AddHandler(AddressOf MyErrorHandler)
      
      Console.WriteLine("Demonstrating a PARSING error:")
      uc.EvalStr("123//456")
      
      Console.WriteLine("")
      Console.WriteLine("Demonstrating an EVALUATION error:")
      uc.Error.TrapOnDivideByZero = true
      uc.EvalStr("5/0")
   End Sub
End Module
				
			
Demonstrating a PARSING error:
--- Error Captured ---
Message: Syntax error
Symbol: '/'
Location: 3
Expression: '123//456'

Demonstrating an EVALUATION error:
--- Error Captured ---
Message: Division by 0
Symbol: ''
Location: 0
Expression: ''
Demonstrates getting the last error message after a failed operation.
				
					using uCalcSoftware;

var uc = new uCalc();
// Attempt to evaluate an expression with unbalanced parenthesis causing a syntax error.
uc.EvalStr("5 * (10 +");

// Check the error message from the last operation.
Console.WriteLine($"Last error message: {uc.Error.Message}");
				
			
Last error message: Bracket delimiter error
				
					#include <iostream>
#include "uCalc.h"

using namespace std;
using namespace uCalcSoftware;

int main() {
   uCalc uc;
   // Attempt to evaluate an expression with unbalanced parenthesis causing a syntax error.
   uc.EvalStr("5 * (10 +");

   // Check the error message from the last operation.
   cout << "Last error message: " << uc.Error().Message() << endl;
}
				
			
Last error message: Bracket delimiter error
				
					Imports System
Imports uCalcSoftware
Public Module Program
   Public Sub Main()
      Dim uc As New uCalc()
      '// Attempt to evaluate an expression with unbalanced parenthesis causing a syntax error.
      uc.EvalStr("5 * (10 +")
      
      '// Check the error message from the last operation.
      Console.WriteLine($"Last error message: {uc.Error.Message}")
   End Sub
End Module
				
			
Last error message: Bracket delimiter error
Retrieves the generic message for a specific error code and compares it to the last error message.
				
					using uCalcSoftware;

var uc = new uCalc();
// Retrieve the built-in message for a specific error code, without triggering an error.
Console.WriteLine($"Generic 'Undefined Identifier' message: {uc.Error.GetMessage(ErrorCode.Undefined_Identifier)}");

// Now, trigger a specific error by using an undefined variable.
uc.EvalStr("MyUndefinedVar + 5");

// Check the message and number for the last error that occurred.
Console.WriteLine($"Last error message: {uc.Error.Message}");
Console.WriteLine($"Last error number: {(int)uc.Error.Code}");
				
			
Generic 'Undefined Identifier' message: Undefined identifier
Last error message: Undefined identifier
Last error number: 258
				
					#include <iostream>
#include "uCalc.h"

using namespace std;
using namespace uCalcSoftware;

int main() {
   uCalc uc;
   // Retrieve the built-in message for a specific error code, without triggering an error.
   cout << "Generic 'Undefined Identifier' message: " << uc.Error().GetMessage(ErrorCode::Undefined_Identifier) << endl;

   // Now, trigger a specific error by using an undefined variable.
   uc.EvalStr("MyUndefinedVar + 5");

   // Check the message and number for the last error that occurred.
   cout << "Last error message: " << uc.Error().Message() << endl;
   cout << "Last error number: " << (int)uc.Error().Code() << endl;
}
				
			
Generic 'Undefined Identifier' message: Undefined identifier
Last error message: Undefined identifier
Last error number: 258
				
					Imports System
Imports uCalcSoftware
Public Module Program
   Public Sub Main()
      Dim uc As New uCalc()
      '// Retrieve the built-in message for a specific error code, without triggering an error.
      Console.WriteLine($"Generic 'Undefined Identifier' message: {uc.Error.GetMessage(ErrorCode.Undefined_Identifier)}")
      
      '// Now, trigger a specific error by using an undefined variable.
      uc.EvalStr("MyUndefinedVar + 5")
      
      '// Check the message and number for the last error that occurred.
      Console.WriteLine($"Last error message: {uc.Error.Message}")
      Console.WriteLine($"Last error number: {CType(uc.Error.Code, Integer)}")
   End Sub
End Module
				
			
Generic 'Undefined Identifier' message: Undefined identifier
Last error message: Undefined identifier
Last error number: 258
Internal Test: Verifies that the error state is correctly cleared after a subsequent successful operation.
				
					using uCalcSoftware;

var uc = new uCalc();
// Internal Test: Verify error state is cleared
Console.WriteLine("--- Testing Error State Lifecycle ---");

// 1. Trigger a division-by-zero error.
uc.Error.TrapOnDivideByZero = true;
uc.EvalStr("1 / 0");
Console.WriteLine($"Message after 1/0: '{uc.Error.Message}'");
Console.WriteLine($"Error number is not None: {uc.Error.Code != ErrorCode.None}");

// 2. Perform a successful operation, which should clear the previous error state.
uc.EvalStr("1 + 1");

// 3. Verify the error message and number have been reset.
Console.WriteLine($"Message after successful op: '{uc.Error.Message}'");
Console.WriteLine($"Error number is now None: {uc.Error.Code == ErrorCode.None}");
				
			
--- Testing Error State Lifecycle ---
Message after 1/0: 'Division by 0'
Error number is not None: True
Message after successful op: 'No error'
Error number is now None: True
				
					#include <iostream>
#include "uCalc.h"

using namespace std;
using namespace uCalcSoftware;

#define tf(IsTrue) ((IsTrue) ? "True" : "False")

int main() {
   uCalc uc;
   // Internal Test: Verify error state is cleared
   cout << "--- Testing Error State Lifecycle ---" << endl;

   // 1. Trigger a division-by-zero error.
   uc.Error().TrapOnDivideByZero(true);
   uc.EvalStr("1 / 0");
   cout << "Message after 1/0: '" << uc.Error().Message() << "'" << endl;
   cout << "Error number is not None: " << tf(uc.Error().Code() != ErrorCode::None) << endl;

   // 2. Perform a successful operation, which should clear the previous error state.
   uc.EvalStr("1 + 1");

   // 3. Verify the error message and number have been reset.
   cout << "Message after successful op: '" << uc.Error().Message() << "'" << endl;
   cout << "Error number is now None: " << tf(uc.Error().Code() == ErrorCode::None) << endl;
}
				
			
--- Testing Error State Lifecycle ---
Message after 1/0: 'Division by 0'
Error number is not None: True
Message after successful op: 'No error'
Error number is now None: True
				
					Imports System
Imports uCalcSoftware
Public Module Program
   Public Sub Main()
      Dim uc As New uCalc()
      '// Internal Test: Verify error state is cleared
      Console.WriteLine("--- Testing Error State Lifecycle ---")
      
      '// 1. Trigger a division-by-zero error.
      uc.Error.TrapOnDivideByZero = true
      uc.EvalStr("1 / 0")
      Console.WriteLine($"Message after 1/0: '{uc.Error.Message}'")
      Console.WriteLine($"Error number is not None: {uc.Error.Code <> ErrorCode.None}")
      
      '// 2. Perform a successful operation, which should clear the previous error state.
      uc.EvalStr("1 + 1")
      
      '// 3. Verify the error message and number have been reset.
      Console.WriteLine($"Message after successful op: '{uc.Error.Message}'")
      Console.WriteLine($"Error number is now None: {uc.Error.Code = ErrorCode.None}")
   End Sub
End Module
				
			
--- Testing Error State Lifecycle ---
Message after 1/0: 'Division by 0'
Error number is not None: True
Message after successful op: 'No error'
Error number is now None: True
Practical: Creates a robust error handler that automatically defines variables on-the-fly when an 'Undefined Identifier' error occurs.
				
					using uCalcSoftware;

var uc = new uCalc();

// This error handler allows you to use variables that were not
// explicitly defined previously by defining unrecognized identifiers
// as variables instead of returning an error.
static void AutoVariableDef(Handle_uCalc h) {
   var uc = new uCalc(h);
   if (uc.Error.Code == ErrorCode.Undefined_Identifier) {
      uc.DefineVariable(uc.Error.Symbol);
      uc.Error.Response = ErrorHandlerResponse.Resume;
   }
}


uc.Error.AddHandler(AutoVariableDef);
// The handler will automatically define 'AutoTest' on first use.
Console.WriteLine(uc.Eval("AutoTest = 123"));
Console.WriteLine(uc.Eval("AutoTest * 1000"));
				
			
123
123000
				
					#include <iostream>
#include "uCalc.h"

using namespace std;
using namespace uCalcSoftware;

// This error handler allows you to use variables that were not
// explicitly defined previously by defining unrecognized identifiers
// as variables instead of returning an error.
void ucalc_call AutoVariableDef(Handle_uCalc h) {
   auto uc = uCalc(h);
   if (uc.Error().Code() == ErrorCode::Undefined_Identifier) {
      uc.DefineVariable(uc.Error().Symbol());
      uc.Error().Response(ErrorHandlerResponse::Resume);
   }
}

int main() {
   uCalc uc;
   uc.Error().AddHandler(AutoVariableDef);
   // The handler will automatically define 'AutoTest' on first use.
   cout << uc.Eval("AutoTest = 123") << endl;
   cout << uc.Eval("AutoTest * 1000") << endl;
}
				
			
123
123000
				
					Imports System
Imports uCalcSoftware
Public Module Program
   
   '// This error handler allows you to use variables that were not
   '// explicitly defined previously by defining unrecognized identifiers
   '// as variables instead of returning an error.
   Public Sub AutoVariableDef(ByVal h As Handle_uCalc)
      Dim uc As New uCalc(h)
      If uc.Error.Code = ErrorCode.Undefined_Identifier Then
         uc.DefineVariable(uc.Error.Symbol)
         uc.Error.Response = ErrorHandlerResponse.Resume
      End If
   End Sub
   
   Public Sub Main()
      Dim uc As New uCalc()
      uc.Error.AddHandler(AddressOf AutoVariableDef)
      '// The handler will automatically define 'AutoTest' on first use.
      Console.WriteLine(uc.Eval("AutoTest = 123"))
      Console.WriteLine(uc.Eval("AutoTest * 1000"))
   End Sub
End Module
				
			
123
123000
Error handler to auto-define variables
				
					using uCalcSoftware;

var uc = new uCalc();

// This error handler allows you to use variables that were not
// explicitly defined previously, by defining the unrecognized identifiers
// as variables instead of returning an error
static void AutoVariableDef(Handle_uCalc h) {
   var uc = new uCalc(h);
   if (uc.Error.Code == ErrorCode.Undefined_Identifier) {
      uc.DefineVariable(uc.Error.Symbol);
      uc.Error.Response = ErrorHandlerResponse.Resume;
   }
}


uc.Error.AddHandler(AutoVariableDef);
Console.WriteLine(uc.Eval("AutoTest = 123"));
Console.WriteLine(uc.Eval("AutoTest * 1000"));
				
			
123
123000
				
					#include <iostream>
#include "uCalc.h"

using namespace std;
using namespace uCalcSoftware;

// This error handler allows you to use variables that were not
// explicitly defined previously, by defining the unrecognized identifiers
// as variables instead of returning an error
void ucalc_call AutoVariableDef(Handle_uCalc h) {
   auto uc = uCalc(h);
   if (uc.Error().Code() == ErrorCode::Undefined_Identifier) {
      uc.DefineVariable(uc.Error().Symbol());
      uc.Error().Response(ErrorHandlerResponse::Resume);
   }
}

int main() {
   uCalc uc;
   uc.Error().AddHandler(AutoVariableDef);
   cout << uc.Eval("AutoTest = 123") << endl;
   cout << uc.Eval("AutoTest * 1000") << endl;
}
				
			
123
123000
				
					Imports System
Imports uCalcSoftware
Public Module Program
   
   '// This error handler allows you to use variables that were not
   '// explicitly defined previously, by defining the unrecognized identifiers
   '// as variables instead of returning an error
   Public Sub AutoVariableDef(ByVal h As Handle_uCalc)
      Dim uc As New uCalc(h)
      If uc.Error.Code = ErrorCode.Undefined_Identifier Then
         uc.DefineVariable(uc.Error.Symbol)
         uc.Error.Response = ErrorHandlerResponse.Resume
      End If
   End Sub
   
   Public Sub Main()
      Dim uc As New uCalc()
      uc.Error.AddHandler(AddressOf AutoVariableDef)
      Console.WriteLine(uc.Eval("AutoTest = 123"))
      Console.WriteLine(uc.Eval("AutoTest * 1000"))
   End Sub
End Module
				
			
123
123000
Internal Test: Verifies that only the division by zero flag is affected, while other floating-point exceptions like overflow remain unchanged by default.
				
					using uCalcSoftware;

var uc = new uCalc();
// Enable only the division by zero error
uc.Error.TrapOnDivideByZero = true;

// This should now raise a uCalc error
Console.WriteLine($"Test 1 (Div by Zero): {uc.EvalStr("1/0")}");

// This should still return 'inf' by default, as we didn't enable overflow errors
Console.WriteLine($"Test 2 (Overflow): {uc.EvalStr("1e308 * 2")}");

// For comparison, enable overflow errors as well
uc.Error.TrapOnOverflow = true;
Console.WriteLine($"Test 3 (Overflow with error): {uc.EvalStr("1e308 * 2")}");
				
			
Test 1 (Div by Zero): Division by 0
Test 2 (Overflow): inf
Test 3 (Overflow with error): Floating point overflow
				
					#include <iostream>
#include "uCalc.h"

using namespace std;
using namespace uCalcSoftware;

int main() {
   uCalc uc;
   // Enable only the division by zero error
   uc.Error().TrapOnDivideByZero(true);

   // This should now raise a uCalc error
   cout << "Test 1 (Div by Zero): " << uc.EvalStr("1/0") << endl;

   // This should still return 'inf' by default, as we didn't enable overflow errors
   cout << "Test 2 (Overflow): " << uc.EvalStr("1e308 * 2") << endl;

   // For comparison, enable overflow errors as well
   uc.Error().TrapOnOverflow(true);
   cout << "Test 3 (Overflow with error): " << uc.EvalStr("1e308 * 2") << endl;
}
				
			
Test 1 (Div by Zero): Division by 0
Test 2 (Overflow): inf
Test 3 (Overflow with error): Floating point overflow
				
					Imports System
Imports uCalcSoftware
Public Module Program
   Public Sub Main()
      Dim uc As New uCalc()
      '// Enable only the division by zero error
      uc.Error.TrapOnDivideByZero = true
      
      '// This should now raise a uCalc error
      Console.WriteLine($"Test 1 (Div by Zero): {uc.EvalStr("1/0")}")
      
      '// This should still return 'inf' by default, as we didn't enable overflow errors
      Console.WriteLine($"Test 2 (Overflow): {uc.EvalStr("1e308 * 2")}")
      
      '// For comparison, enable overflow errors as well
      uc.Error.TrapOnOverflow = true
      Console.WriteLine($"Test 3 (Overflow with error): {uc.EvalStr("1e308 * 2")}")
   End Sub
End Module
				
			
Test 1 (Div by Zero): Division by 0
Test 2 (Overflow): inf
Test 3 (Overflow with error): Floating point overflow
Succinctly demonstrates toggling the error-raising behavior for division by zero.
				
					using uCalcSoftware;

var uc = new uCalc();
// Default behavior: returns infinity
Console.WriteLine($"Default: {uc.EvalStr("1/0")}");

// Enable error raising
uc.Error.TrapOnDivideByZero = true;
Console.WriteLine($"Error Enabled: {uc.EvalStr("1/0")}");

// Disable error raising
uc.Error.TrapOnDivideByZero = false;
Console.WriteLine($"Error Disabled: {uc.EvalStr("1/0")}");
				
			
Default: inf
Error Enabled: Division by 0
Error Disabled: inf
				
					#include <iostream>
#include "uCalc.h"

using namespace std;
using namespace uCalcSoftware;

int main() {
   uCalc uc;
   // Default behavior: returns infinity
   cout << "Default: " << uc.EvalStr("1/0") << endl;

   // Enable error raising
   uc.Error().TrapOnDivideByZero(true);
   cout << "Error Enabled: " << uc.EvalStr("1/0") << endl;

   // Disable error raising
   uc.Error().TrapOnDivideByZero(false);
   cout << "Error Disabled: " << uc.EvalStr("1/0") << endl;
}
				
			
Default: inf
Error Enabled: Division by 0
Error Disabled: inf
				
					Imports System
Imports uCalcSoftware
Public Module Program
   Public Sub Main()
      Dim uc As New uCalc()
      '// Default behavior: returns infinity
      Console.WriteLine($"Default: {uc.EvalStr("1/0")}")
      
      '// Enable error raising
      uc.Error.TrapOnDivideByZero = true
      Console.WriteLine($"Error Enabled: {uc.EvalStr("1/0")}")
      
      '// Disable error raising
      uc.Error.TrapOnDivideByZero = false
      Console.WriteLine($"Error Disabled: {uc.EvalStr("1/0")}")
   End Sub
End Module
				
			
Default: inf
Error Enabled: Division by 0
Error Disabled: inf
RaiseErrorOnDivideByZero
				
					using uCalcSoftware;

var uc = new uCalc();
Console.WriteLine(uc.EvalStr("1/0"));
uc.Error.TrapOnDivideByZero = true;
Console.WriteLine(uc.EvalStr("1/0"));

Console.WriteLine(uc.EvalStr("Sqrt(-1)"));
uc.Error.TrapOnInvalid = true;
Console.WriteLine(uc.EvalStr("Sqrt(-1)"));

Console.WriteLine(uc.EvalStr("5*10^308"));
uc.Error.TrapOnOverflow = true;
Console.WriteLine(uc.EvalStr("5*10^308"));

Console.WriteLine(uc.EvalStr("10^-308/10000"));
uc.Error.TrapOnUnderflow = true;
Console.WriteLine(uc.EvalStr("10^-308/10000"));
				
			
inf
Division by 0
nan
Invalid operation
inf
Floating point overflow
0
Floating point underflow
				
					#include <iostream>
#include "uCalc.h"

using namespace std;
using namespace uCalcSoftware;

int main() {
   uCalc uc;
   cout << uc.EvalStr("1/0") << endl;
   uc.Error().TrapOnDivideByZero(true);
   cout << uc.EvalStr("1/0") << endl;

   cout << uc.EvalStr("Sqrt(-1)") << endl;
   uc.Error().TrapOnInvalid(true);
   cout << uc.EvalStr("Sqrt(-1)") << endl;

   cout << uc.EvalStr("5*10^308") << endl;
   uc.Error().TrapOnOverflow(true);
   cout << uc.EvalStr("5*10^308") << endl;

   cout << uc.EvalStr("10^-308/10000") << endl;
   uc.Error().TrapOnUnderflow(true);
   cout << uc.EvalStr("10^-308/10000") << endl;
}
				
			
inf
Division by 0
nan
Invalid operation
inf
Floating point overflow
0
Floating point underflow
				
					Imports System
Imports uCalcSoftware
Public Module Program
   Public Sub Main()
      Dim uc As New uCalc()
      Console.WriteLine(uc.EvalStr("1/0"))
      uc.Error.TrapOnDivideByZero = true
      Console.WriteLine(uc.EvalStr("1/0"))
      
      Console.WriteLine(uc.EvalStr("Sqrt(-1)"))
      uc.Error.TrapOnInvalid = true
      Console.WriteLine(uc.EvalStr("Sqrt(-1)"))
      
      Console.WriteLine(uc.EvalStr("5*10^308"))
      uc.Error.TrapOnOverflow = true
      Console.WriteLine(uc.EvalStr("5*10^308"))
      
      Console.WriteLine(uc.EvalStr("10^-308/10000"))
      uc.Error.TrapOnUnderflow = true
      Console.WriteLine(uc.EvalStr("10^-308/10000"))
   End Sub
End Module
				
			
inf
Division by 0
nan
Invalid operation
inf
Floating point overflow
0
Floating point underflow
Raising floating point errors with FloatingPointErrorsToTrap
				
					using uCalcSoftware;

var uc = new uCalc();
Console.WriteLine(uc.Error.FloatingPointErrorsToTrap);
Console.WriteLine(uc.EvalStr("1/0"));
Console.WriteLine(uc.EvalStr("0/0"));
Console.WriteLine(uc.EvalStr("5*10^308"));
Console.WriteLine(uc.EvalStr("10^-308/10000"));

Console.WriteLine("--- Raise Div-by-0 ---");
uc.Error.FloatingPointErrorsToTrap = (int)ErrorCode.FloatDivisionByZero;
Console.WriteLine(uc.Error.FloatingPointErrorsToTrap);
Console.WriteLine(uc.EvalStr("1/0"));
Console.WriteLine(uc.EvalStr("0/0"));
Console.WriteLine(uc.EvalStr("5*10^308"));
Console.WriteLine(uc.EvalStr("10^-308/10000"));

Console.WriteLine("--- Raise overflow ---");
uc.Error.FloatingPointErrorsToTrap = (int)ErrorCode.FloatOverflow;
Console.WriteLine(uc.Error.FloatingPointErrorsToTrap);
Console.WriteLine(uc.EvalStr("1/0"));
Console.WriteLine(uc.EvalStr("0/0"));
Console.WriteLine(uc.EvalStr("5*10^308"));
Console.WriteLine(uc.EvalStr("10^-308/10000"));

Console.WriteLine("--- Raise invalid & underflow ---");
uc.Error.SetFloatingPointErrorsToTrap(ErrorCode.FloatInvalid, ErrorCode.FloatUnderflow);
Console.WriteLine(uc.Error.FloatingPointErrorsToTrap); // ErrorCode::FloatInvalid + ErrorCode::FloatUnderflow
Console.WriteLine(uc.EvalStr("1/0"));
Console.WriteLine(uc.EvalStr("0/0"));
Console.WriteLine(uc.EvalStr("5*10^308"));
Console.WriteLine(uc.EvalStr("10^-308/10000"));
				
			
0
inf
nan
inf
0
--- Raise Div-by-0 ---
8
Division by 0
nan
inf
0
--- Raise overflow ---
4
Floating point overflow
nan
Floating point overflow
0
--- Raise invalid & underflow ---
18
inf
Invalid operation
inf
Floating point underflow
				
					#include <iostream>
#include "uCalc.h"

using namespace std;
using namespace uCalcSoftware;

int main() {
   uCalc uc;
   cout << uc.Error().FloatingPointErrorsToTrap() << endl;
   cout << uc.EvalStr("1/0") << endl;
   cout << uc.EvalStr("0/0") << endl;
   cout << uc.EvalStr("5*10^308") << endl;
   cout << uc.EvalStr("10^-308/10000") << endl;

   cout << "--- Raise Div-by-0 ---" << endl;
   uc.Error().FloatingPointErrorsToTrap((int)ErrorCode::FloatDivisionByZero);
   cout << uc.Error().FloatingPointErrorsToTrap() << endl;
   cout << uc.EvalStr("1/0") << endl;
   cout << uc.EvalStr("0/0") << endl;
   cout << uc.EvalStr("5*10^308") << endl;
   cout << uc.EvalStr("10^-308/10000") << endl;

   cout << "--- Raise overflow ---" << endl;
   uc.Error().FloatingPointErrorsToTrap((int)ErrorCode::FloatOverflow);
   cout << uc.Error().FloatingPointErrorsToTrap() << endl;
   cout << uc.EvalStr("1/0") << endl;
   cout << uc.EvalStr("0/0") << endl;
   cout << uc.EvalStr("5*10^308") << endl;
   cout << uc.EvalStr("10^-308/10000") << endl;

   cout << "--- Raise invalid & underflow ---" << endl;
   uc.Error().SetFloatingPointErrorsToTrap(ErrorCode::FloatInvalid, ErrorCode::FloatUnderflow);
   cout << uc.Error().FloatingPointErrorsToTrap() << endl; // ErrorCode::FloatInvalid + ErrorCode::FloatUnderflow
   cout << uc.EvalStr("1/0") << endl;
   cout << uc.EvalStr("0/0") << endl;
   cout << uc.EvalStr("5*10^308") << endl;
   cout << uc.EvalStr("10^-308/10000") << endl;
}
				
			
0
inf
nan
inf
0
--- Raise Div-by-0 ---
8
Division by 0
nan
inf
0
--- Raise overflow ---
4
Floating point overflow
nan
Floating point overflow
0
--- Raise invalid & underflow ---
18
inf
Invalid operation
inf
Floating point underflow
				
					Imports System
Imports uCalcSoftware
Public Module Program
   Public Sub Main()
      Dim uc As New uCalc()
      Console.WriteLine(uc.Error.FloatingPointErrorsToTrap)
      Console.WriteLine(uc.EvalStr("1/0"))
      Console.WriteLine(uc.EvalStr("0/0"))
      Console.WriteLine(uc.EvalStr("5*10^308"))
      Console.WriteLine(uc.EvalStr("10^-308/10000"))
      
      Console.WriteLine("--- Raise Div-by-0 ---")
      uc.Error.FloatingPointErrorsToTrap = CInt(ErrorCode.FloatDivisionByZero)
      Console.WriteLine(uc.Error.FloatingPointErrorsToTrap)
      Console.WriteLine(uc.EvalStr("1/0"))
      Console.WriteLine(uc.EvalStr("0/0"))
      Console.WriteLine(uc.EvalStr("5*10^308"))
      Console.WriteLine(uc.EvalStr("10^-308/10000"))
      
      Console.WriteLine("--- Raise overflow ---")
      uc.Error.FloatingPointErrorsToTrap = CInt(ErrorCode.FloatOverflow)
      Console.WriteLine(uc.Error.FloatingPointErrorsToTrap)
      Console.WriteLine(uc.EvalStr("1/0"))
      Console.WriteLine(uc.EvalStr("0/0"))
      Console.WriteLine(uc.EvalStr("5*10^308"))
      Console.WriteLine(uc.EvalStr("10^-308/10000"))
      
      Console.WriteLine("--- Raise invalid & underflow ---")
      uc.Error.SetFloatingPointErrorsToTrap(ErrorCode.FloatInvalid, ErrorCode.FloatUnderflow)
      Console.WriteLine(uc.Error.FloatingPointErrorsToTrap) '// ErrorCode::FloatInvalid + ErrorCode::FloatUnderflow
      Console.WriteLine(uc.EvalStr("1/0"))
      Console.WriteLine(uc.EvalStr("0/0"))
      Console.WriteLine(uc.EvalStr("5*10^308"))
      Console.WriteLine(uc.EvalStr("10^-308/10000"))
   End Sub
End Module
				
			
0
inf
nan
inf
0
--- Raise Div-by-0 ---
8
Division by 0
nan
inf
0
--- Raise overflow ---
4
Floating point overflow
nan
Floating point overflow
0
--- Raise invalid & underflow ---
18
inf
Invalid operation
inf
Floating point underflow
Registers a handler to log when division by zero occurs.
				
					using uCalcSoftware;

var uc = new uCalc();

static void LogAndResume(Handle_uCalc h) {
   var uc = new uCalc(h);
   Console.WriteLine($"Logged error: {uc.Error.Message}");
   uc.Error.Response = ErrorHandlerResponse.Resume;
}


uc.Error.TrapOnDivideByZero = true;
uc.Error.AddHandler(LogAndResume);

Console.WriteLine("Start");
var Result = uc.Eval("5/0");   // Division by zero
Console.WriteLine("End");
				
			
Start
Logged error: Division by 0
End
				
					#include <iostream>
#include "uCalc.h"

using namespace std;
using namespace uCalcSoftware;

void ucalc_call LogAndResume(Handle_uCalc h) {
   auto uc = uCalc(h);
   cout << "Logged error: " << uc.Error().Message() << endl;
   uc.Error().Response(ErrorHandlerResponse::Resume);
}

int main() {
   uCalc uc;
   uc.Error().TrapOnDivideByZero(true);
   uc.Error().AddHandler(LogAndResume);

   cout << "Start" << endl;
   auto Result = uc.Eval("5/0");   // Division by zero
   cout << "End" << endl;
}
				
			
Start
Logged error: Division by 0
End
				
					Imports System
Imports uCalcSoftware
Public Module Program
   
   Public Sub LogAndResume(ByVal h As Handle_uCalc)
      Dim uc As New uCalc(h)
      Console.WriteLine($"Logged error: {uc.Error.Message}")
      uc.Error.Response = ErrorHandlerResponse.Resume
   End Sub
   
   Public Sub Main()
      Dim uc As New uCalc()
      uc.Error.TrapOnDivideByZero = true
      uc.Error.AddHandler(AddressOf LogAndResume)
      
      Console.WriteLine("Start")
      Dim Result = uc.Eval("5/0")   '// Division by zero
      Console.WriteLine("End")
   End Sub
End Module
				
			
Start
Logged error: Division by 0
End
Error handler order
				
					using uCalcSoftware;

var uc = new uCalc();

static void ErrorHandlerA(Handle_uCalc h) {
   var uc = new uCalc(h);
   Console.WriteLine("Handler A called");
}

static void ErrorHandlerB(Handle_uCalc h) {
   var uc = new uCalc(h);
   Console.WriteLine("Handler B called");
}

static void ErrorHandlerC(Handle_uCalc h) {
   var uc = new uCalc(h);
   Console.WriteLine("Handler C called");
}

static void ErrorHandlerD(Handle_uCalc h) {
   var uc = new uCalc(h);
   Console.WriteLine("Handler D called");
}

static void ErrorHandlerE(Handle_uCalc h) {
   var uc = new uCalc(h);
   Console.WriteLine("Handler E called");
}


uc.Error.AddHandler(ErrorHandlerA);
uc.Error.AddHandler(ErrorHandlerB);
uc.Error.AddHandler(ErrorHandlerC);
uc.Error.AddHandler(ErrorHandlerD, -1);
uc.Error.AddHandler(ErrorHandlerE, 3);

Console.WriteLine(uc.EvalStr("10 / "));
				
			
Handler C called
Handler B called
Handler A called
Handler E called
Handler D called
Syntax error
				
					#include <iostream>
#include "uCalc.h"

using namespace std;
using namespace uCalcSoftware;

void ucalc_call ErrorHandlerA(Handle_uCalc h) {
   auto uc = uCalc(h);
   cout << "Handler A called" << endl;
}

void ucalc_call ErrorHandlerB(Handle_uCalc h) {
   auto uc = uCalc(h);
   cout << "Handler B called" << endl;
}

void ucalc_call ErrorHandlerC(Handle_uCalc h) {
   auto uc = uCalc(h);
   cout << "Handler C called" << endl;
}

void ucalc_call ErrorHandlerD(Handle_uCalc h) {
   auto uc = uCalc(h);
   cout << "Handler D called" << endl;
}

void ucalc_call ErrorHandlerE(Handle_uCalc h) {
   auto uc = uCalc(h);
   cout << "Handler E called" << endl;
}

int main() {
   uCalc uc;
   uc.Error().AddHandler(ErrorHandlerA);
   uc.Error().AddHandler(ErrorHandlerB);
   uc.Error().AddHandler(ErrorHandlerC);
   uc.Error().AddHandler(ErrorHandlerD, -1);
   uc.Error().AddHandler(ErrorHandlerE, 3);

   cout << uc.EvalStr("10 / ") << endl;
}
				
			
Handler C called
Handler B called
Handler A called
Handler E called
Handler D called
Syntax error
				
					Imports System
Imports uCalcSoftware
Public Module Program
   
   Public Sub ErrorHandlerA(ByVal h As Handle_uCalc)
      Dim uc As New uCalc(h)
      Console.WriteLine("Handler A called")
   End Sub
   
   Public Sub ErrorHandlerB(ByVal h As Handle_uCalc)
      Dim uc As New uCalc(h)
      Console.WriteLine("Handler B called")
   End Sub
   
   Public Sub ErrorHandlerC(ByVal h As Handle_uCalc)
      Dim uc As New uCalc(h)
      Console.WriteLine("Handler C called")
   End Sub
   
   Public Sub ErrorHandlerD(ByVal h As Handle_uCalc)
      Dim uc As New uCalc(h)
      Console.WriteLine("Handler D called")
   End Sub
   
   Public Sub ErrorHandlerE(ByVal h As Handle_uCalc)
      Dim uc As New uCalc(h)
      Console.WriteLine("Handler E called")
   End Sub
   
   Public Sub Main()
      Dim uc As New uCalc()
      uc.Error.AddHandler(AddressOf ErrorHandlerA)
      uc.Error.AddHandler(AddressOf ErrorHandlerB)
      uc.Error.AddHandler(AddressOf ErrorHandlerC)
      uc.Error.AddHandler(AddressOf ErrorHandlerD, -1)
      uc.Error.AddHandler(AddressOf ErrorHandlerE, 3)
      
      Console.WriteLine(uc.EvalStr("10 / "))
   End Sub
End Module
				
			
Handler C called
Handler B called
Handler A called
Handler E called
Handler D called
Syntax error
A succinct example showing a function that unconditionally raises a custom error.
				
					using uCalcSoftware;

var uc = new uCalc();

static void MyHandler(Handle_uCalc h) {
   var uc = new uCalc(h);
   // This handler just logs the error and aborts
   Console.WriteLine($"Error Handler Caught: {uc.Error.Message}");
}
static void MyFunc(uCalc.Callback cb) {
   // This function always fails with a custom message
   cb.Error.Raise("Validation failed for input.");
}

uc.Error.AddHandler(MyHandler);
uc.DefineFunction("Validate()", MyFunc);
uc.EvalStr("Validate()"); // This call will trigger the error
				
			
Error Handler Caught: Validation failed for input.
				
					#include <iostream>
#include "uCalc.h"

using namespace std;
using namespace uCalcSoftware;

void ucalc_call MyHandler(Handle_uCalc h) {
   auto uc = uCalc(h);
   // This handler just logs the error and aborts
   cout << "Error Handler Caught: " << uc.Error().Message() << endl;
}
void ucalc_call MyFunc(uCalcBase::Callback cb) {
   // This function always fails with a custom message
   cb.Error().Raise("Validation failed for input.");
}
int main() {
   uCalc uc;
   uc.Error().AddHandler(MyHandler);
   uc.DefineFunction("Validate()", MyFunc);
   uc.EvalStr("Validate()"); // This call will trigger the error
}
				
			
Error Handler Caught: Validation failed for input.
				
					Imports System
Imports uCalcSoftware
Public Module Program
   
   Public Sub MyHandler(ByVal h As Handle_uCalc)
      Dim uc As New uCalc(h)
      '// This handler just logs the error and aborts
      Console.WriteLine($"Error Handler Caught: {uc.Error.Message}")
   End Sub
   Public Sub MyFunc(ByVal cb As uCalc.Callback)
      '// This function always fails with a custom message
      cb.Error.Raise("Validation failed for input.")
   End Sub
   Public Sub Main()
      Dim uc As New uCalc()
      uc.Error.AddHandler(AddressOf MyHandler)
      uc.DefineFunction("Validate()", AddressOf MyFunc)
      uc.EvalStr("Validate()") '// This call will trigger the error
   End Sub
End Module
				
			
Error Handler Caught: Validation failed for input.
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