uCalc API Version: 5.7.0-preview.1 Released: 7/30/2026

Warning

uCalc API Preview Release Notice:This preview documentation describes the intended behavior of the API. It is not fully accurate or complete.The current preview build contains incomplete features, unoptimized performance, and is subject to breaking changes.Use of the preview version in your production code is not recommended.

Error = [ErrorInfo]

Property

Product: 

Fast Math Parser

Class: 

uCalc

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

Remarks

Examples

Adding an error handler callback

ID: 1

See: AddHandler, Code = [ErrorCode], Error = [ErrorInfo], Error handling and control flow, Expression = [string], Introduction, Location = [int], Message = [string], Symbol = [string], TrapOnDivideByZero = [bool] 
				
					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
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					#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
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					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
Explore 600+ other examples
Internal Test: Verifies that the error code is correctly cleared after a successful operation.

ID: 327

See: Code = [ErrorCode], Error = [ErrorInfo] 
				
					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
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					#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
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					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
Explore 600+ other examples
Creating an error handler that automatically defines variables on the fly by checking for an 'Undefined Identifier' error.

ID: 326

See: Code = [ErrorCode], Error = [ErrorInfo], Error handling and control flow 
				
					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
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					#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
Explore 600+ other examples
				
					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
Explore 600+ other examples
Checking the error code for a simple syntax error using a callback.

ID: 325

See: Code = [ErrorCode], Error = [ErrorInfo] 
				
					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
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					#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
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					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
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An internal test to confirm that ErrorExpression returns an empty string for an error triggered manually by a user function during evaluation.

ID: 318

See: Error = [ErrorInfo], Expression = [string] 
				
					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!
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					#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!
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					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!
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Capturing both parsing-stage and evaluation-stage errors to see how ErrorLocation behaves differently.

ID: 321

See: Error = [ErrorInfo], Location = [int] 
				
					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: ''
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					#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: ''
Explore 600+ other examples
				
					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: ''
Explore 600+ other examples
Demonstrates getting the last error message after a failed operation.

ID: 322

See: Error = [ErrorInfo], Message = [string] 
				
					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
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					#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
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					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
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Retrieves the generic message for a specific error code and compares it to the last error message.

ID: 323

See: Code = [ErrorCode], Error = [ErrorInfo], Message = [string] 
				
					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
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					#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
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					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
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Internal Test: Verifies that the error state is correctly cleared after a subsequent successful operation.

ID: 324

See: Code = [ErrorCode], Error = [ErrorInfo], Message = [string] 
				
					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
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					#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
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					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
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Practical: Creates a robust error handler that automatically defines variables on-the-fly when an 'Undefined Identifier' error occurs.

ID: 329

See: Code = [ErrorCode], Error = [ErrorInfo], Response = [ErrorHandlerResponse] 
				
					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
Explore 600+ other examples
				
					#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
Explore 600+ other examples
				
					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
Explore 600+ other examples
Error handler to auto-define variables

ID: 54

See: AddHandler, Error = [ErrorInfo], Response = [ErrorHandlerResponse] 
				
					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
Explore 600+ other examples
				
					#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
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					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
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Internal Test: Verifies that only the division by zero flag is affected, while other floating-point exceptions like overflow remain unchanged by default.

ID: 405

See: Error = [ErrorInfo], TrapOnDivideByZero = [bool], TrapOnOverflow = [bool] 
				
					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
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					#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
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					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
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Toggling the error-raising behavior for division by zero.

ID: 403

See: Error = [ErrorInfo], TrapOnDivideByZero = [bool] 
				
					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
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					#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
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					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
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RaiseErrorOnDivideByZero

ID: 80

See: Error = [ErrorInfo], TrapOnDivideByZero = [bool], TrapOnInvalid = [bool], TrapOnOverflow = [bool], TrapOnUnderflow = [bool] 
				
					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
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					#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
Explore 600+ other examples
				
					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
Explore 600+ other examples
Raising floating point errors with FloatingPointErrorsToTrap

ID: 74

See: Error = [ErrorInfo], FloatingPointErrorsToTrap = [Int32] 
				
					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
Explore 600+ other examples
				
					#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
Explore 600+ other examples
				
					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
Explore 600+ other examples
Registers a handler to log when division by zero occurs.

ID: 258

See: AddHandler, Error = [ErrorInfo] 
				
					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
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					#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
Explore 600+ other examples
				
					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
Explore 600+ other examples
Error handler order

ID: 55

See: AddHandler, Error = [ErrorInfo], Error handling and control flow 
				
					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
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					#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
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					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
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A function that unconditionally raises a custom error.

ID: 482

See: Error = [ErrorInfo], Error = [ErrorInfo], Raise(string) 
				
					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.
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					#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.
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					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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A practical example of a proactive error handler that automatically defines undeclared variables on the fly, allowing the expression to successfully resume execution.

ID: 1190

See: AddHandler, Error = [ErrorInfo], Error handling and control flow, ErrorCode, ErrorHandlerResponse, Handling Errors, Response = [ErrorHandlerResponse] 
				
					using uCalcSoftware;

var uc = new uCalc();

// This handler automatically defines variables when they are first used.
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) {
      Console.WriteLine($"Handler: '{uc.Error.Symbol}' is undefined. Defining it now.");
      uc.DefineVariable(uc.Error.Symbol);

      // Tell the engine to resume the operation
      uc.Error.Response = ErrorHandlerResponse.Resume;
   }
}


uc.Error.AddHandler(AutoDefineHandler);

// 'my_var' doesn't exist yet, but the handler will create it.
var result = uc.EvalStr("my_var = 100; my_var = my_var * 2");

Console.WriteLine($"Final result: {result}");
				
			
Handler: 'my_var' is undefined. Defining it now.
Final result: 200
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					#include <iostream>
#include "uCalc.h"

using namespace std;
using namespace uCalcSoftware;

// This handler automatically defines variables when they are first used.
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) {
      cout << "Handler: '" << uc.Error().Symbol() << "' is undefined. Defining it now." << endl;
      uc.DefineVariable(uc.Error().Symbol());

      // Tell the engine to resume the operation
      uc.Error().Response(ErrorHandlerResponse::Resume);
   }
}

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

   // 'my_var' doesn't exist yet, but the handler will create it.
   auto result = uc.EvalStr("my_var = 100; my_var = my_var * 2");

   cout << "Final result: " << result << endl;
}
				
			
Handler: 'my_var' is undefined. Defining it now.
Final result: 200
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					Imports System
Imports uCalcSoftware
Public Module Program
   
   '// This handler automatically defines variables when they are first used.
   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
         Console.WriteLine($"Handler: '{uc.Error.Symbol}' is undefined. Defining it now.")
         uc.DefineVariable(uc.Error.Symbol)
         
         '// Tell the engine to resume the operation
         uc.Error.Response = ErrorHandlerResponse.Resume
      End If
   End Sub
   
   Public Sub Main()
      Dim uc As New uCalc()
      uc.Error.AddHandler(AddressOf AutoDefineHandler)
      
      '// 'my_var' doesn't exist yet, but the handler will create it.
      Dim result = uc.EvalStr("my_var = 100; my_var = my_var * 2")
      
      Console.WriteLine($"Final result: {result}")
   End Sub
End Module
				
			
Handler: 'my_var' is undefined. Defining it now.
Final result: 200
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