Literal

The Literal token in RCParsing matches a specific string exactly. It’s used for parsing fixed strings, such as keywords or operators.

Overview

The Literal token matches a predefined string, optionally with case-insensitive comparison. It produces the original construction-specified string as its intermediate value.

Example

Here’s an example of matching a keyword:

var builder = new ParserBuilder();

builder.CreateToken("if")
    .Literal("if");

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

With case-insensitive matching:

builder.CreateToken("if")
    .Literal("if", StringComparison.OrdinalIgnoreCase);

builder.CreateToken("else")
    .LiteralIgnoreCase("else");

var parser = builder.Build();

var result1 = parser.MatchToken("if", "If");
var result2 = parser.MatchToken("else", "ElSe");

var value1 = result1.GetIntermediateValue<string>(); // "if"
var value2 = result2.GetIntermediateValue<string>(); // "else"

Use Cases

• Operators: Parse symbols like + or =.
• Fixed Strings: Match specific string literals in the grammar.

Intermediate Values

The Literal token produces the original string that was specified in token construction as its intermediate value:

builder.CreateToken("operator")
    .Literal("+");

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

Notes

• Case Sensitivity: Use StringComparison for case-insensitive matching.
• Efficient Matching: Uses a trie for fast lookup.
• Simple Match: Matches exactly the specified string without additional checks, for keywords use Keyword token instead.

Related Tutorials

• LiteralChar Token
• LiteralChoice Token
• Keyword Token