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.

Matching by token name ({@Token})

Product: 

Class: 

Remarks

Description: A high-precision matcher that identifies a token by its specific internal name (ID) rather than its general category.

The {@Token} directive is the most granular matching tool in the uCalc::Transformer. While other directives match broad categories (like {@Number} or {@Whitespace}), {@Token} allows you to target a single, specific entry in the engine's token table.

Why use {@Token}?

In advanced parser development, you often need to distinguish between tokens that look identical but serve different structural roles. For example:

  • Internal Shortcuts: Directives like {@dq} are actually shortcuts for {@Token(_Token_QuoteChar_Double)}.
  • Custom Tokens: If you have added a specialized token via uCalc.Tokens.Add with a unique name like MyCustomSeparator, you can target it specifically using {@Token(MyCustomSeparator)}.

Comparison: Category vs. Token

FeatureCategory Matcher (e.g., {@Bracket})Token Matcher ({@Token})
ScopeMatches any opening bracket ((, [, {).Matches only the specific token name provided.
PrecisionHigh-level structural matching.Low-level surgical matching.
FlexibilityInherits engine-wide category settings.Strict adherence to a single internal ID.

Inverse Matching with !

The universal inversion operator ! can be applied to this directive:

  • {@Token(Name)}: Matches only the specified token.
  • {!Token(Name)}: Matches any token except the one specified.

Examples

{@Token} - matching a token by name

ID: 185

See: Matching by token name ({@Token}) 
				
					using uCalcSoftware;

var uc = new uCalc();
var t = uc.NewTransformer();
t.FromTo("{@String}", "<Any quoted {@Self}>");
t.FromTo("({@Token(String_Singlequoted)})", "<Single quoted {@Self}>");
t.FromTo("({@Token(String_Doublequoted)})", "<Double quoted {@Self}>");

var s = """
"Test" '123' ("abc") ('xyz')
""";
Console.WriteLine(t.Transform(s));
				
			
<Any quoted "Test"> <Any quoted '123'> <Double quoted ("abc")> <Single quoted ('xyz')>
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					#include <iostream>
#include "uCalc.h"

using namespace std;
using namespace uCalcSoftware;

int main() {
   uCalc uc;
   auto t = uc.NewTransformer();
   t.FromTo("{@String}", "<Any quoted {@Self}>");
   t.FromTo("({@Token(String_Singlequoted)})", "<Single quoted {@Self}>");
   t.FromTo("({@Token(String_Doublequoted)})", "<Double quoted {@Self}>");

   auto s = R"("Test" '123' ("abc") ('xyz'))";
   cout << t.Transform(s) << endl;
}
				
			
<Any quoted "Test"> <Any quoted '123'> <Double quoted ("abc")> <Single quoted ('xyz')>
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					Imports System
Imports uCalcSoftware
Public Module Program
   Public Sub Main()
      Dim uc As New uCalc()
      Dim t = uc.NewTransformer()
      t.FromTo("{@String}", "<Any quoted {@Self}>")
      t.FromTo("({@Token(String_Singlequoted)})", "<Single quoted {@Self}>")
      t.FromTo("({@Token(String_Doublequoted)})", "<Double quoted {@Self}>")
      
      Dim s = """Test"" '123' (""abc"") ('xyz')"
      Console.WriteLine(t.Transform(s))
   End Sub
End Module
				
			
<Any quoted "Test"> <Any quoted '123'> <Double quoted ("abc")> <Single quoted ('xyz')>
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Displays the complete list of default token definitions, showing their type, internal name, and regex pattern.

ID: 70

See: Count = [int], ExpressionTokens = [Tokens], IndexOf, Introduction, Matching by token name ({@Token}), Name = [string], Regex = [string], At, Tokens 
				
					using uCalcSoftware;

var uc = new uCalc();
// Lists all tokens currently defined for the expression evaluator.

Console.WriteLine($"Token Count: {uc.ExpressionTokens.Count}");
Console.WriteLine("");
Console.WriteLine("Index  Type  Name: regex");
Console.WriteLine("========================");
var Tokens = uc.ExpressionTokens;
foreach(var token in Tokens) {
   Console.Write(Tokens.IndexOf(token));
   Console.WriteLine($"  {token.Description}  {token.Name}: {token.Regex}");
}

// Note that the expression evaluator token list has a few extra tokens,
// related to hex/bin/oct notation, string interpolation, and imaginary number
// notation, which are not found in the default Transformer token list.
				
			
Token Count: 30

Index  Type  Name: regex
========================
0  generic  _token_line: .*
1  generic  _token_catchall: .
2  generic  _token_catchall_utf8_other: [\xf0-\xf7][\x80-\xbf][\x80-\xbf][\x80-\xbf]|[\xe0-\xef][\x80-\xbf][\x80-\xbf]|[\xc0-\xdf][\x80-\xbf]
3  generic  _token_punctuation: (--|\.{3}|\xE2\x80\xA6|[!"#$%&'()*+,\-./:;<=>?@\[\\\]^_`{|}~]|\xE2\x80[\x90-\x95])
4  generic  _token_quotechar: ("){3}|"|'
5  generic  _token_quotechar_single: '
6  generic  _token_quotechar_double: "
7  generic  _token_quotechar_tripledouble: """
8  memberaccess  _token_memberaccess: \.
9  generic  _token_variableargs: \.\.\.
10  reducible  _token_reducible2: [-:|+/*^&=%@!`\\<>?#$~]+
11  bracket  _token_parenthesis: \(
12  bracketclose  _token_parenthesis_close: \)
13  bracket  _token_curlybrace: \{
14  bracketclose  _token_curlybrace_close: \}
15  bracket  _token_squarebracket: \[
16  bracketclose  _token_squarebracket_close: \]
17  argseparator  _token_argseparator: ,
18  statementseparator  _token_newline: (?:\r?\n)|\r
19  statementseparator  _token_semicolon: ;
20  literal  _token_string_singlequoted: '([^']*(?:''[^']*)*)'
21  literal  _token_string_doublequoted: "([^"]*(?:""[^"]*)*)"
22  literal  _token_string_tripledoublequoted: """([\s\S]*?)"""
23  whitespace  _token_whitespace: [\t\v ]+
24  reducible  _token_reducible: [-:|+/*^&=%@!`\\<>?]+
25  literal  _token_floatnumber: [0-9]*\.?[0-9]+([eE][+-]?[0-9]+)?
26  alphanumeric  _token_alphanumeric: [a-zA-Z_][a-zA-Z0-9_]*
27  literal  _token_imaginaryunit: #i
28  tokentransform  _token_binaryhexoctalnotation: #[bho][0-9A-F]+
29  tokentransform  _token_stringinterpolationquote: \$['"]
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					#include <iostream>
#include "uCalc.h"

using namespace std;
using namespace uCalcSoftware;

int main() {
   uCalc uc;
   // Lists all tokens currently defined for the expression evaluator.

   cout << "Token Count: " << uc.ExpressionTokens().Count() << endl;
   cout << "" << endl;
   cout << "Index  Type  Name: regex" << endl;
   cout << "========================" << endl;
   auto Tokens = uc.ExpressionTokens();
   for(auto token : Tokens) {
      cout << Tokens.IndexOf(token);
      cout << "  " << token.Description() << "  " << token.Name() << ": " << token.Regex() << endl;
   }

   // Note that the expression evaluator token list has a few extra tokens,
   // related to hex/bin/oct notation, string interpolation, and imaginary number
   // notation, which are not found in the default Transformer token list.
}
				
			
Token Count: 30

Index  Type  Name: regex
========================
0  generic  _token_line: .*
1  generic  _token_catchall: .
2  generic  _token_catchall_utf8_other: [\xf0-\xf7][\x80-\xbf][\x80-\xbf][\x80-\xbf]|[\xe0-\xef][\x80-\xbf][\x80-\xbf]|[\xc0-\xdf][\x80-\xbf]
3  generic  _token_punctuation: (--|\.{3}|\xE2\x80\xA6|[!"#$%&'()*+,\-./:;<=>?@\[\\\]^_`{|}~]|\xE2\x80[\x90-\x95])
4  generic  _token_quotechar: ("){3}|"|'
5  generic  _token_quotechar_single: '
6  generic  _token_quotechar_double: "
7  generic  _token_quotechar_tripledouble: """
8  memberaccess  _token_memberaccess: \.
9  generic  _token_variableargs: \.\.\.
10  reducible  _token_reducible2: [-:|+/*^&=%@!`\\<>?#$~]+
11  bracket  _token_parenthesis: \(
12  bracketclose  _token_parenthesis_close: \)
13  bracket  _token_curlybrace: \{
14  bracketclose  _token_curlybrace_close: \}
15  bracket  _token_squarebracket: \[
16  bracketclose  _token_squarebracket_close: \]
17  argseparator  _token_argseparator: ,
18  statementseparator  _token_newline: (?:\r?\n)|\r
19  statementseparator  _token_semicolon: ;
20  literal  _token_string_singlequoted: '([^']*(?:''[^']*)*)'
21  literal  _token_string_doublequoted: "([^"]*(?:""[^"]*)*)"
22  literal  _token_string_tripledoublequoted: """([\s\S]*?)"""
23  whitespace  _token_whitespace: [\t\v ]+
24  reducible  _token_reducible: [-:|+/*^&=%@!`\\<>?]+
25  literal  _token_floatnumber: [0-9]*\.?[0-9]+([eE][+-]?[0-9]+)?
26  alphanumeric  _token_alphanumeric: [a-zA-Z_][a-zA-Z0-9_]*
27  literal  _token_imaginaryunit: #i
28  tokentransform  _token_binaryhexoctalnotation: #[bho][0-9A-F]+
29  tokentransform  _token_stringinterpolationquote: \$['"]
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					Imports System
Imports uCalcSoftware
Public Module Program
   Public Sub Main()
      Dim uc As New uCalc()
      '// Lists all tokens currently defined for the expression evaluator.
      
      Console.WriteLine($"Token Count: {uc.ExpressionTokens.Count}")
      Console.WriteLine("")
      Console.WriteLine("Index  Type  Name: regex")
      Console.WriteLine("========================")
      Dim Tokens = uc.ExpressionTokens
      For Each token In Tokens
         Console.Write(Tokens.IndexOf(token))
         Console.WriteLine($"  {token.Description}  {token.Name}: {token.Regex}")
      Next
      
      '// Note that the expression evaluator token list has a few extra tokens,
      '// related to hex/bin/oct notation, string interpolation, and imaginary number
      '// notation, which are not found in the default Transformer token list.
   End Sub
End Module
				
			
Token Count: 30

Index  Type  Name: regex
========================
0  generic  _token_line: .*
1  generic  _token_catchall: .
2  generic  _token_catchall_utf8_other: [\xf0-\xf7][\x80-\xbf][\x80-\xbf][\x80-\xbf]|[\xe0-\xef][\x80-\xbf][\x80-\xbf]|[\xc0-\xdf][\x80-\xbf]
3  generic  _token_punctuation: (--|\.{3}|\xE2\x80\xA6|[!"#$%&'()*+,\-./:;<=>?@\[\\\]^_`{|}~]|\xE2\x80[\x90-\x95])
4  generic  _token_quotechar: ("){3}|"|'
5  generic  _token_quotechar_single: '
6  generic  _token_quotechar_double: "
7  generic  _token_quotechar_tripledouble: """
8  memberaccess  _token_memberaccess: \.
9  generic  _token_variableargs: \.\.\.
10  reducible  _token_reducible2: [-:|+/*^&=%@!`\\<>?#$~]+
11  bracket  _token_parenthesis: \(
12  bracketclose  _token_parenthesis_close: \)
13  bracket  _token_curlybrace: \{
14  bracketclose  _token_curlybrace_close: \}
15  bracket  _token_squarebracket: \[
16  bracketclose  _token_squarebracket_close: \]
17  argseparator  _token_argseparator: ,
18  statementseparator  _token_newline: (?:\r?\n)|\r
19  statementseparator  _token_semicolon: ;
20  literal  _token_string_singlequoted: '([^']*(?:''[^']*)*)'
21  literal  _token_string_doublequoted: "([^"]*(?:""[^"]*)*)"
22  literal  _token_string_tripledoublequoted: """([\s\S]*?)"""
23  whitespace  _token_whitespace: [\t\v ]+
24  reducible  _token_reducible: [-:|+/*^&=%@!`\\<>?]+
25  literal  _token_floatnumber: [0-9]*\.?[0-9]+([eE][+-]?[0-9]+)?
26  alphanumeric  _token_alphanumeric: [a-zA-Z_][a-zA-Z0-9_]*
27  literal  _token_imaginaryunit: #i
28  tokentransform  _token_binaryhexoctalnotation: #[bho][0-9A-F]+
29  tokentransform  _token_stringinterpolationquote: \$['"]
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