Character

The Character token in RCParsing matches a single character based on a predicate. It’s a flexible way to match specific characters without hardcoding them.

Overview

The Character token uses a predicate function to determine if a single character matches. It does not produce an intermediate value by default, but you can use combinators like CaptureText to capture the matched character.

Example

Here’s an example of matching a lowercase letter:

var builder = new ParserBuilder();

builder.CreateToken("lowercase")
    .Char(c => c >= 'a' && c <= 'z');

var parser = builder.Build();
var result = parser.MatchToken("lowercase", "x");

With captured text:

builder.CreateToken("lowercase")
    .CaptureText(b => b.Char(c => c >= 'a' && c <= 'z'));

var parser = builder.Build();
var result = parser.MatchToken("lowercase", "x");
var value = result.GetIntermediateValue<string>(); // "x"

Use Cases

• Specific Characters: Match letters, digits, or custom character sets.
• Flexible Matching: Use predicates for dynamic character selection.
• Simple Tokens: Define single-character tokens with custom rules.

Intermediate Values

The Character token does not produce an intermediate value unless wrapped with a combinator:

builder.CreateToken("digit")
    .CaptureText(b => b.Char(c => char.IsDigit(c)));

var parser = builder.Build();
var result = parser.ParseRule("digit", "5");
var value = result.GetIntermediateValue<string>(); // "5"

Notes

• Single Character: Matches exactly one character.
• Predicate-Based: Use any boolean function to define valid characters.

Related Tutorials

• RepeatCharacters Token
• Identifier Token
• LiteralChar Token