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.

IsChildRule = [bool]

Property

Product: 

Transformer Library

Class: 

Rule

Determines if a rule belongs to a nested (local) transformer rather than the main (root) transformer.

Remarks

🌳 Understanding Rule Hierarchy

The IsChildRule property is a boolean flag that indicates whether a rule is part of a nested parsing context. It returns true if the rule was defined on a 'local' transformer—one obtained from another rule's LocalTransformer property. This is a key introspection tool for understanding the scope and hierarchy of your transformation logic.

  • Parent Rule (Root): A rule defined directly on a main Transformer object. For these rules, IsChildRule returns false.
  • Child Rule (Local): A rule defined on the Transformer object returned by another rule's @LocalTransformer() property. For these rules, IsChildRule returns true.

This property allows you to distinguish between top-level patterns and sub-patterns that only execute within the scope of a specific parent match. This is crucial for debugging complex, nested parsing logic or for writing generic functions that behave differently based on a rule's scope.

💡 Why uCalc? (Comparative Analysis)

  • vs. Regular Expressions: Standard regex engines have a 'flat' model; there is no concept of a rule hierarchy. Achieving nested parsing requires complex and often fragile recursive patterns or lookarounds. uCalc's LocalTransformer creates a true hierarchical parsing model, and IsChildRule is the built-in tool to inspect this structure. It provides a level of architectural clarity that is absent in traditional regex.

  • vs. Parser Generators (ANTLR, etc.): While parser generators define grammars with clear hierarchical rules (e.g., a statement contains an expression), this hierarchy is static and defined in a grammar file. uCalc's model is entirely dynamic and programmatic. You can build and query these parent-child relationships at runtime, and IsChildRule is the primary way to do so.

Examples

Basic distinction between a root rule and a child rule.

ID: 937

See: IsChildRule = [bool] 
				
					using uCalcSoftware;

var uc = new uCalc();
var t = new uCalc.Transformer();
var rootRule = t.Pattern("root");
var localTransformer = rootRule.LocalTransformer;
var childRule = localTransformer.Pattern("child");

Console.WriteLine($"Is 'rootRule' a child? {rootRule.IsChildRule}");
Console.WriteLine($"Is 'childRule' a child? {childRule.IsChildRule}");
				
			
Is 'rootRule' a child? False
Is 'childRule' a child? True
Explore 600+ other examples
				
					#include <iostream>
#include "uCalc.h"

using namespace std;
using namespace uCalcSoftware;

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

int main() {
   uCalc uc;
   uCalc::Transformer t;
   auto rootRule = t.Pattern("root");
   auto localTransformer = rootRule.LocalTransformer();
   auto childRule = localTransformer.Pattern("child");

   cout << "Is 'rootRule' a child? " << tf(rootRule.IsChildRule()) << endl;
   cout << "Is 'childRule' a child? " << tf(childRule.IsChildRule()) << endl;
}
				
			
Is 'rootRule' a child? False
Is 'childRule' a child? True
Explore 600+ other examples
				
					Imports System
Imports uCalcSoftware
Public Module Program
   Public Sub Main()
      Dim uc As New uCalc()
      Dim t As New uCalc.Transformer()
      Dim rootRule = t.Pattern("root")
      Dim localTransformer = rootRule.LocalTransformer
      Dim childRule = localTransformer.Pattern("child")
      
      Console.WriteLine($"Is 'rootRule' a child? {rootRule.IsChildRule}")
      Console.WriteLine($"Is 'childRule' a child? {childRule.IsChildRule}")
   End Sub
End Module
				
			
Is 'rootRule' a child? False
Is 'childRule' a child? True
Explore 600+ other examples
Internal Test: Verifies that any rule not on the root transformer is considered a child, regardless of nesting depth.

ID: 938

See: IsChildRule = [bool] 
				
					using uCalcSoftware;

var uc = new uCalc();
var t = new uCalc.Transformer();
var grandParentRule = t.Pattern("grandparent");

// Create a child
var parentTransformer = grandParentRule.LocalTransformer;
var parentRule = parentTransformer.Pattern("parent");

// Create a grandchild
var childTransformer = parentRule.LocalTransformer;
var childRule = childTransformer.Pattern("child");

Console.WriteLine($"Grandparent is child: {grandParentRule.IsChildRule}");
Console.WriteLine($"Parent is child: {parentRule.IsChildRule}");
Console.WriteLine($"Child (grandchild) is child: {childRule.IsChildRule}");
				
			
Grandparent is child: False
Parent is child: True
Child (grandchild) is child: True
Explore 600+ other examples
				
					#include <iostream>
#include "uCalc.h"

using namespace std;
using namespace uCalcSoftware;

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

int main() {
   uCalc uc;
   uCalc::Transformer t;
   auto grandParentRule = t.Pattern("grandparent");

   // Create a child
   auto parentTransformer = grandParentRule.LocalTransformer();
   auto parentRule = parentTransformer.Pattern("parent");

   // Create a grandchild
   auto childTransformer = parentRule.LocalTransformer();
   auto childRule = childTransformer.Pattern("child");

   cout << "Grandparent is child: " << tf(grandParentRule.IsChildRule()) << endl;
   cout << "Parent is child: " << tf(parentRule.IsChildRule()) << endl;
   cout << "Child (grandchild) is child: " << tf(childRule.IsChildRule()) << endl;
}
				
			
Grandparent is child: False
Parent is child: True
Child (grandchild) is child: True
Explore 600+ other examples
				
					Imports System
Imports uCalcSoftware
Public Module Program
   Public Sub Main()
      Dim uc As New uCalc()
      Dim t As New uCalc.Transformer()
      Dim grandParentRule = t.Pattern("grandparent")
      
      '// Create a child
      Dim parentTransformer = grandParentRule.LocalTransformer
      Dim parentRule = parentTransformer.Pattern("parent")
      
      '// Create a grandchild
      Dim childTransformer = parentRule.LocalTransformer
      Dim childRule = childTransformer.Pattern("child")
      
      Console.WriteLine($"Grandparent is child: {grandParentRule.IsChildRule}")
      Console.WriteLine($"Parent is child: {parentRule.IsChildRule}")
      Console.WriteLine($"Child (grandchild) is child: {childRule.IsChildRule}")
   End Sub
End Module
				
			
Grandparent is child: False
Parent is child: True
Child (grandchild) is child: True
Explore 600+ other examples
LocalTransformer, HasLocalTransformer, IsChildRule

ID: 126

See: HasLocalTransformer = [bool], IsChildRule = [bool], LocalTransformer = [Transformer] 
				
					using uCalcSoftware;

var uc = new uCalc();
// Note the change in section/div/h2
var t = uc.NewTransformer();

var rule = t.Pattern("<section>{body}</section>").SetStatementSensitive(false);
var section = rule.LocalTransformer;
section.FromTo("<h2>{text}</h2>", "<h1>====> {@Eval: UCase(text)} <====</h1>");
section.SkipOver("&{entity};");
var ch = section.FromTo("<p>{text}</p>", "<p>SELECTED: {text}</p>");

Console.WriteLine($"Has a local transformer: {rule.HasLocalTransformer}");
Console.WriteLine($"rule is a child rule: {rule.IsChildRule}");
Console.WriteLine($"ch is a child rule: {ch.IsChildRule}");

var HtmlText =
"""

<div class="article" data-id="1">
  <h2>Article One</h2>
  <p>This is the first article.</p>
</div>

<div class="article" data-id="2">
  <h2>Article Two</h2>
  <p>This is the second article.</p>
</div>

<section>
  <div class="article" data-id="3">
    <h2>Article Three</h2>
    <p>This one is inside a &lt;section&gt;.</p>
  </div>
</section>

<div class="article" data-id="4">
  <h2>Article Four</h2>
  <p>This is the fourth article.</p>
</div>

""";

t.Text = HtmlText;
t.Transform();
Console.WriteLine(t.Text);


				
			
Has a local transformer: True
rule is a child rule: False
ch is a child rule: True

<div class="article" data-id="1">
  <h2>Article One</h2>
  <p>This is the first article.</p>
</div>

<div class="article" data-id="2">
  <h2>Article Two</h2>
  <p>This is the second article.</p>
</div>

<section>
  <div class="article" data-id="3">
    <h1>====> ARTICLE THREE <====</h1>
    <p>SELECTED: This one is inside a &lt;section&gt;.</p>
  </div>
</section>

<div class="article" data-id="4">
  <h2>Article Four</h2>
  <p>This is the fourth article.</p>
</div>
Explore 600+ other examples
				
					#include <iostream>
#include "uCalc.h"

using namespace std;
using namespace uCalcSoftware;

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

int main() {
   uCalc uc;
   // Note the change in section/div/h2
   auto t = uc.NewTransformer();

   auto rule = t.Pattern("<section>{body}</section>").SetStatementSensitive(false);
   auto section = rule.LocalTransformer();
   section.FromTo("<h2>{text}</h2>", "<h1>====> {@Eval: UCase(text)} <====</h1>");
   section.SkipOver("&{entity};");
   auto ch = section.FromTo("<p>{text}</p>", "<p>SELECTED: {text}</p>");

   cout << "Has a local transformer: " << tf(rule.HasLocalTransformer()) << endl;
   cout << "rule is a child rule: " << tf(rule.IsChildRule()) << endl;
   cout << "ch is a child rule: " << tf(ch.IsChildRule()) << endl;

   auto HtmlText =
   R"(
<div class="article" data-id="1">
  <h2>Article One</h2>
  <p>This is the first article.</p>
</div>

<div class="article" data-id="2">
  <h2>Article Two</h2>
  <p>This is the second article.</p>
</div>

<section>
  <div class="article" data-id="3">
    <h2>Article Three</h2>
    <p>This one is inside a &lt;section&gt;.</p>
  </div>
</section>

<div class="article" data-id="4">
  <h2>Article Four</h2>
  <p>This is the fourth article.</p>
</div>
)";

   t.Text(HtmlText);
   t.Transform();
   cout << t.Text() << endl;


}
				
			
Has a local transformer: True
rule is a child rule: False
ch is a child rule: True

<div class="article" data-id="1">
  <h2>Article One</h2>
  <p>This is the first article.</p>
</div>

<div class="article" data-id="2">
  <h2>Article Two</h2>
  <p>This is the second article.</p>
</div>

<section>
  <div class="article" data-id="3">
    <h1>====> ARTICLE THREE <====</h1>
    <p>SELECTED: This one is inside a &lt;section&gt;.</p>
  </div>
</section>

<div class="article" data-id="4">
  <h2>Article Four</h2>
  <p>This is the fourth article.</p>
</div>
Explore 600+ other examples
				
					Imports System
Imports uCalcSoftware
Public Module Program
   Public Sub Main()
      Dim uc As New uCalc()
      '// Note the change in section/div/h2
      Dim t = uc.NewTransformer()
      
      Dim rule = t.Pattern("<section>{body}</section>").SetStatementSensitive(false)
      Dim section = rule.LocalTransformer
      section.FromTo("<h2>{text}</h2>", "<h1>====> {@Eval: UCase(text)} <====</h1>")
      section.SkipOver("&{entity};")
      Dim ch = section.FromTo("<p>{text}</p>", "<p>SELECTED: {text}</p>")
      
      Console.WriteLine($"Has a local transformer: {rule.HasLocalTransformer}")
      Console.WriteLine($"rule is a child rule: {rule.IsChildRule}")
      Console.WriteLine($"ch is a child rule: {ch.IsChildRule}")
      
      Dim HtmlText =
      "
<div class=""article"" data-id=""1"">
  <h2>Article One</h2>
  <p>This is the first article.</p>
</div>

<div class=""article"" data-id=""2"">
  <h2>Article Two</h2>
  <p>This is the second article.</p>
</div>

<section>
  <div class=""article"" data-id=""3"">
    <h2>Article Three</h2>
    <p>This one is inside a &lt;section&gt;.</p>
  </div>
</section>

<div class=""article"" data-id=""4"">
  <h2>Article Four</h2>
  <p>This is the fourth article.</p>
</div>
"
      
      t.Text = HtmlText
      t.Transform()
      Console.WriteLine(t.Text)
      
      
   End Sub
End Module
				
			
Has a local transformer: True
rule is a child rule: False
ch is a child rule: True

<div class="article" data-id="1">
  <h2>Article One</h2>
  <p>This is the first article.</p>
</div>

<div class="article" data-id="2">
  <h2>Article Two</h2>
  <p>This is the second article.</p>
</div>

<section>
  <div class="article" data-id="3">
    <h1>====> ARTICLE THREE <====</h1>
    <p>SELECTED: This one is inside a &lt;section&gt;.</p>
  </div>
</section>

<div class="article" data-id="4">
  <h2>Article Four</h2>
  <p>This is the fourth article.</p>
</div>
Explore 600+ other examples