RepeatCharacters

The RepeatCharacters token in RCParsing matches a sequence of characters based on a predicate, within a specified range of repetitions. It’s useful for parsing sequences like digits or letters.

Overview

The RepeatCharacters token matches one or more characters that satisfy a predicate, with optional minimum and maximum repetition counts. Variants like ZeroOrMoreChars and OneOrMoreChars simplify common cases. It does not produce an intermediate value by default.

Example

Here’s an example of matching multiple digits:

var builder = new ParserBuilder();

builder.CreateToken("digits")
    .OneOrMoreChars(c => char.IsDigit(c));

var parser = builder.Build();
var result = parser.MatchToken("digits", "12345");

With captured text:

builder.CreateToken("digits")
    .CaptureText(b => b.OneOrMoreChars(c => char.IsDigit(c)));

var parser = builder.Build();
var result = parser.MatchToken("digits", "12345");
var value = result.GetIntermediateValue<string>(); // "12345"

Use Cases

• Digit Sequences: Parse sequences like phone numbers or IDs.
• Letter Sequences: Match words or identifiers with specific character sets.
• Custom Patterns: Define repeated character patterns with predicates.

Intermediate Values

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

builder.CreateToken("letters")
    .CaptureText(b => b.Chars(c => char.IsLetter(c), min: 2, max: 5));

var parser = builder.Build();
var result = parser.MatchToken("letters", "helloo");
var value = result.GetIntermediateValue<string>(); // "hello"

Notes

• Range Specification: Use min and max to control repetitions.
• Variants: ZeroOrMoreChars and OneOrMoreChars are shortcuts.

Related Tutorials

• Character Token
• Identifier Token
• Repeat Token