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.

Nested Patterns

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Class: 

Remarks

uCalc allows you to group segments of a pattern using curly braces { ... }. This is primarily used to delimit the scope of Alternative Parts (|) or to create complex structures inside variables.

Recursive Nesting:Patterns can be nested arbitrarily deep. For example:

  • An Alternation { A | B } can contain an Optional part [ ... ].
  • That Optional part can contain another Alternation or group.
  • This flexibility allows you to model complex grammar structures like Menu { Open [ Recent { File | Project } ] | Save }.

Syntax:

  • Anonymous Grouping: Start { OptionA | OptionB } End
    • The braces define where the alternation begins and ends.
  • Named Grouping (Capture): {name: OptionA | OptionB }
    • Matches the pattern inside and captures the result into the variable {name}.

Ambiguity Resolution:Since {name} denotes a variable and { pattern } denotes a group, uCalc distinguishes them based on content:

  1. Variable: A simple name (e.g., {x}).
  2. Group: Contains structure like alternatives | or multiple tokens (e.g., { A | B }).

Comparative Analysis: Why uCalc?

  • vs. Regex Groups (...):
    • Consistency: Regex uses parentheses () for grouping and capturing. uCalc uses curly braces {} for everything—variables, groups, and blocks. This creates a unified syntax where "everything dynamic is in braces."
    • Non-Capturing by Default: In Regex, (A|B) captures automatically (Group 1). You have to use (?:A|B) to avoid capturing. In uCalc, { A | B } is purely structural (non-capturing) unless you explicitly name it {val: A | B}. This avoids "index shifting" bugs.
  • vs. EBNF:
    • Familiarity: uCalc's syntax is very close to EBNF (Extended Backus-Naur Form), making it intuitive for developers familiar with language grammar definitions.

Examples

Grouping alternatives to limit scope.

ID: 242

See: Nested Patterns 
				
					using uCalcSoftware;

var uc = new uCalc();
var t = uc.NewTransformer();
// Matches "File Open" or "File Close".
// Capture needs explicit naming.
t.FromTo("File {cmd: Open | Close }", "Command: {cmd}");

Console.WriteLine(t.Transform("File Open"));
Console.WriteLine(t.Transform("File Close"));
				
			
Command: Open
Command: Close
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					#include <iostream>
#include "uCalc.h"

using namespace std;
using namespace uCalcSoftware;

int main() {
   uCalc uc;
   auto t = uc.NewTransformer();
   // Matches "File Open" or "File Close".
   // Capture needs explicit naming.
   t.FromTo("File {cmd: Open | Close }", "Command: {cmd}");

   cout << t.Transform("File Open") << endl;
   cout << t.Transform("File Close") << endl;
}
				
			
Command: Open
Command: Close
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					Imports System
Imports uCalcSoftware
Public Module Program
   Public Sub Main()
      Dim uc As New uCalc()
      Dim t = uc.NewTransformer()
      '// Matches "File Open" or "File Close". 
      '// Capture needs explicit naming.
      t.FromTo("File {cmd: Open | Close }", "Command: {cmd}")
      
      Console.WriteLine(t.Transform("File Open"))
      Console.WriteLine(t.Transform("File Close"))
   End Sub
End Module
				
			
Command: Open
Command: Close
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Nested grouping for complex commands.

ID: 243

See: Nested Patterns 
				
					using uCalcSoftware;

var uc = new uCalc();
var t = uc.NewTransformer();
// Pattern: "Set" followed by (Color OR (Size followed by Big/Small))
t.FromTo("Set {prop: Color | Size { Big | Small } }", "Property: {prop}");

Console.WriteLine(t.Transform("Set Color"));
Console.WriteLine(t.Transform("Set Size Big"));
Console.WriteLine(t.Transform("Set Size Small"));
				
			
Property: Color
Property: Size Big
Property: Size Small
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					#include <iostream>
#include "uCalc.h"

using namespace std;
using namespace uCalcSoftware;

int main() {
   uCalc uc;
   auto t = uc.NewTransformer();
   // Pattern: "Set" followed by (Color OR (Size followed by Big/Small))
   t.FromTo("Set {prop: Color | Size { Big | Small } }", "Property: {prop}");

   cout << t.Transform("Set Color") << endl;
   cout << t.Transform("Set Size Big") << endl;
   cout << t.Transform("Set Size Small") << endl;
}
				
			
Property: Color
Property: Size Big
Property: Size Small
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					Imports System
Imports uCalcSoftware
Public Module Program
   Public Sub Main()
      Dim uc As New uCalc()
      Dim t = uc.NewTransformer()
      '// Pattern: "Set" followed by (Color OR (Size followed by Big/Small))
      t.FromTo("Set {prop: Color | Size { Big | Small } }", "Property: {prop}")
      
      Console.WriteLine(t.Transform("Set Color"))
      Console.WriteLine(t.Transform("Set Size Big"))
      Console.WriteLine(t.Transform("Set Size Small"))
   End Sub
End Module
				
			
Property: Color
Property: Size Big
Property: Size Small
Explore 600+ other examples
Recursive Nesting: Alternation -> Optional -> Alternation.

ID: 244

See: Nested Patterns 
				
					using uCalcSoftware;

var uc = new uCalc();
var t = uc.NewTransformer();
// Structure:
// 1. Alternation: "Open" OR "Save"
// 2. Inside "Open": Optional "Recent"
// 3. Inside "Recent": Alternation "File" OR "Project"
var pattern = "Menu { Open [ Recent {type: File | Project } ] | Save }";

t.FromTo(pattern, "Action Detected");

Console.WriteLine(t.Transform("Menu Save"));                 // Match (Simple Alternation)
Console.WriteLine(t.Transform("Menu Open"));                 // Match (Optional omitted)
Console.WriteLine(t.Transform("Menu Open Recent File"));     // Match (Deep nesting)
Console.WriteLine(t.Transform("Menu Open Recent Project"));  // Match (Deep nesting alt)
				
			
Action Detected
Action Detected
Action Detected
Action Detected
Explore 600+ other examples
				
					#include <iostream>
#include "uCalc.h"

using namespace std;
using namespace uCalcSoftware;

int main() {
   uCalc uc;
   auto t = uc.NewTransformer();
   // Structure:
   // 1. Alternation: "Open" OR "Save"
   // 2. Inside "Open": Optional "Recent"
   // 3. Inside "Recent": Alternation "File" OR "Project"
   auto pattern = "Menu { Open [ Recent {type: File | Project } ] | Save }";

   t.FromTo(pattern, "Action Detected");

   cout << t.Transform("Menu Save") << endl;                 // Match (Simple Alternation)
   cout << t.Transform("Menu Open") << endl;                 // Match (Optional omitted)
   cout << t.Transform("Menu Open Recent File") << endl;     // Match (Deep nesting)
   cout << t.Transform("Menu Open Recent Project") << endl;  // Match (Deep nesting alt)
}
				
			
Action Detected
Action Detected
Action Detected
Action Detected
Explore 600+ other examples
				
					Imports System
Imports uCalcSoftware
Public Module Program
   Public Sub Main()
      Dim uc As New uCalc()
      Dim t = uc.NewTransformer()
      '// Structure:
      '// 1. Alternation: "Open" OR "Save"
      '// 2. Inside "Open": Optional "Recent"
      '// 3. Inside "Recent": Alternation "File" OR "Project"
      Dim pattern = "Menu { Open [ Recent {type: File | Project } ] | Save }"
      
      t.FromTo(pattern, "Action Detected")
      
      Console.WriteLine(t.Transform("Menu Save"))                 '// Match (Simple Alternation)
      Console.WriteLine(t.Transform("Menu Open"))                 '// Match (Optional omitted)
      Console.WriteLine(t.Transform("Menu Open Recent File"))     '// Match (Deep nesting)
      Console.WriteLine(t.Transform("Menu Open Recent Project"))  '// Match (Deep nesting alt)
   End Sub
End Module
				
			
Action Detected
Action Detected
Action Detected
Action Detected
Explore 600+ other examples