TinyTokenizer 0.4.1

TinyTokenizer

A high-performance, zero-allocation tokenizer library for .NET 8+ with SIMD-optimized character matching.

Features

• High performance — Zero-allocation parsing with SIMD-optimized SearchValues<char>
• TinyAst — Red-green syntax tree with fluent queries, editing, and undo/redo
• Schema system — Unified configuration for tokenization + semantic node definitions
• Semantic nodes — Pattern-based AST matching (function calls, property access, etc.)
• TreeWalker — DOM-style filtered tree traversal
• Async streaming — Tokenize from Stream and PipeReader with IAsyncEnumerable
• Full tokenization — Blocks, strings, numbers, comments, operators, tagged identifiers
• Error recovery — Gracefully handles malformed input and continues parsing

Installation

dotnet add package TinyTokenizer

Or add a reference to the TinyTokenizer project in your solution.

Quick Start

using TinyTokenizer;

// Simple tokenization
var tokens = "func(a, b)".TokenizeToTokens();

// tokens contains:
// - IdentToken("func")
// - BlockToken("(a, b)") with children:
//   - IdentToken("a")
//   - SymbolToken(",")
//   - WhitespaceToken(" ")
//   - IdentToken("b")

// With options
var options = TokenizerOptions.Default
    .WithCommentStyles(CommentStyle.CStyleSingleLine, CommentStyle.CStyleMultiLine);

var tokens = "x = 42; // comment".TokenizeToTokens(options);

TinyAst — Syntax Tree API

TinyTokenizer includes a syntax tree for efficient AST manipulation with fluent queries and undo/redo support.

Quick Start

using TinyTokenizer.Ast;

// Parse source into a syntax tree
var tree = SyntaxTree.Parse("function foo() { return 1; }");

// Query nodes
var idents = tree.Leaves.Where(l => l.Kind == NodeKind.Ident);

// Fluent mutations with undo support
tree.CreateEditor()
    .Replace(Query.Ident.WithText("foo"), "bar")
    .Insert(Query.BraceBlock.First().InnerStart(), "console.log('enter');")
    .Commit();

// Undo/redo
tree.Undo();
tree.Redo();

Querying with NodeQuery

The Query static class provides a fluent CSS-like selector API:

using TinyTokenizer.Ast;

// By kind
Query.Ident                    // All identifiers
Query.Numeric                  // All numbers
Query.String                   // All strings
Query.Operator                 // All operators

// Blocks
Query.BraceBlock               // All { } blocks
Query.BracketBlock             // All [ ] blocks
Query.ParenBlock               // All ( ) blocks
Query.AnyBlock                 // Any block type

// Filters
Query.Ident.WithText("foo")              // Exact match
Query.Ident.WithTextContaining("test")   // Contains
Query.Ident.WithTextStartingWith("_")    // Prefix
Query.Ident.Where(n => n.Width > 5)      // Custom predicate

// Pseudo-selectors
Query.Ident.First()            // First match only
Query.Ident.Last()             // Last match only
Query.Ident.Nth(2)             // Third match (0-indexed)

// Composition
Query.Ident | Query.Numeric    // Union (OR)
Query.Ident & Query.Leaf       // Intersection (AND)

Insertion Positions

Queries resolve to insertion points with position modifiers:

// Relative to matched node
Query.Ident.First().Before()   // Insert before first ident
Query.Ident.First().After()    // Insert after first ident

// Inside blocks
Query.BraceBlock.First().InnerStart()  // After opening {
Query.BraceBlock.First().InnerEnd()    // Before closing }

SyntaxEditor

The SyntaxEditor provides batched mutations with atomic commit:

var tree = SyntaxTree.Parse("a + b");

var editor = tree.CreateEditor();

// Queue multiple edits
editor
    .Replace(Query.Ident.WithText("a"), "x")
    .Replace(Query.Ident.WithText("b"), "y")
    .Insert(Query.Operator.First().Before(), "(")
    .Insert(Query.Operator.First().After(), ")");

// Apply atomically (supports undo)
editor.Commit();

// Or discard
editor.Rollback();

Common SyntaxEditor Patterns

Insert before a function/block:

var tree = SyntaxTree.Parse("function {body}");

tree.CreateEditor()
    .Insert(Query.BraceBlock.First().Before(), "/* decorator */ ")
    .Commit();
// Result: "function /* decorator */ {body}"

Insert at the start of a function body (after opening brace):

var tree = SyntaxTree.Parse("function {existing}");

tree.CreateEditor()
    .Insert(Query.BraceBlock.First().InnerStart(), "console.log('enter'); ")
    .Commit();
// Result: "function {console.log('enter'); existing}"

Insert at the end of a function body (before closing brace):

var tree = SyntaxTree.Parse("function {existing}");

tree.CreateEditor()
    .Insert(Query.BraceBlock.First().InnerEnd(), " return result;")
    .Commit();
// Result: "function {existing return result;}"

Insert after a function/block:

var tree = SyntaxTree.Parse("function {body}");

tree.CreateEditor()
    .Insert(Query.BraceBlock.First().After(), " // end of function")
    .Commit();
// Result: "function {body} // end of function"

Multiple insertions in one commit:

var tree = SyntaxTree.Parse("fn {body}");

tree.CreateEditor()
    .Insert(Query.BraceBlock.First().Before(), "/* before */ ")
    .Insert(Query.BraceBlock.First().InnerStart(), "start(); ")
    .Insert(Query.BraceBlock.First().InnerEnd(), " end();")
    .Insert(Query.BraceBlock.First().After(), " /* after */")
    .Commit();
// Result: "fn /* before */ {start(); body end();} /* after */"

Replace multiple occurrences:

var tree = SyntaxTree.Parse("a + b + a");

tree.CreateEditor()
    .Replace(Query.Ident.WithText("a"), "x")  // Replaces ALL 'a' with 'x'
    .Commit();
// Result: "x + b + x"

Remove nodes:

var tree = SyntaxTree.Parse("keep remove keep");

tree.CreateEditor()
    .Remove(Query.Ident.WithText("remove"))
    .Commit();
// Result: "keep  keep"

The editor supports Insert, Remove, and Replace operations. All changes can be undone with tree.Undo() and redone with tree.Redo().

Schema — Unified Configuration

The Schema class provides unified configuration for both tokenization and semantic node definitions.

Quick Start

using TinyTokenizer.Ast;

// Create a schema with tokenization settings and semantic definitions
var schema = Schema.Create()
    .WithOperators(CommonOperators.JavaScript)
    .WithCommentStyles(CommentStyle.CStyleSingleLine, CommentStyle.CStyleMultiLine)
    .Define(BuiltInDefinitions.FunctionName)
    .Define(BuiltInDefinitions.ArrayAccess)
    .Define(BuiltInDefinitions.PropertyAccess)
    .Define(BuiltInDefinitions.MethodCall)
    .Build();

// Parse with schema
var tree = SyntaxTree.Parse("obj.method(x)", schema);

// Match semantic nodes using the attached schema
var methods = tree.Match<MethodCallNode>().ToList();

Built-in Schema

// Schema.Default includes:
// - CommonOperators.Universal
// - C-style single and multi-line comments
// - FunctionName, ArrayAccess, PropertyAccess, MethodCall definitions
var tree = SyntaxTree.Parse(source, Schema.Default);

Converting from TokenizerOptions

// Create schema from existing TokenizerOptions
var options = TokenizerOptions.Default
    .WithOperators(CommonOperators.CFamily)
    .WithCommentStyles(CommentStyle.CStyleSingleLine);

var schema = Schema.FromOptions(options);

TreeWalker — DOM-Style Traversal

The TreeWalker provides filtered tree traversal similar to the W3C DOM TreeWalker specification.

Basic Usage

var tree = SyntaxTree.Parse("foo { bar(x) }");

// Create walker from tree or node
var walker = tree.CreateTreeWalker();
// or: var walker = new TreeWalker(tree.Root);

// Enumerate all descendants
foreach (var node in walker.DescendantsAndSelf())
{
    Console.WriteLine($"{node.Kind} at {node.Position}");
}

Filtered Traversal

// Filter by node type using NodeFilter flags
var leafWalker = new TreeWalker(tree.Root, NodeFilter.Leaves);
foreach (var leaf in leafWalker.DescendantsAndSelf())
{
    // Only leaf nodes (identifiers, operators, etc.)
}

var blockWalker = new TreeWalker(tree.Root, NodeFilter.Blocks);
foreach (var block in blockWalker.DescendantsAndSelf())
{
    // Only block nodes ({ }, [ ], ( ))
}

Custom Filter Functions

// Use FilterResult for fine-grained control
var walker = new TreeWalker(
    tree.Root,
    NodeFilter.All,
    node => node.Kind == NodeKind.Ident
        ? FilterResult.Accept    // Include this node
        : FilterResult.Skip);    // Skip node, but check children

var idents = walker.DescendantsAndSelf().ToList();

The walker also provides cursor-based navigation (NextNode, ParentNode, FirstChild, etc.) and enumeration methods (Descendants, Ancestors, FollowingSiblings).

Semantic Nodes — AST Pattern Matching

Semantic nodes provide a way to match structural patterns in the AST and create typed wrapper objects.

Quick Start

using TinyTokenizer.Ast;

// Parse with schema
var tree = SyntaxTree.Parse("foo(x) + bar.baz", Schema.Default);

// Find all function names (identifiers followed by parentheses)
var funcNames = tree.Match<FunctionNameNode>().ToList();
// funcNames[0].Name == "foo"

// Find all property accesses
var props = tree.Match<PropertyAccessNode>().ToList();
// props[0].Object == "bar", props[0].Property == "baz"

Built-in Semantic Nodes

Custom Semantic Nodes

Define your own semantic node types:

// 1. Define the node class
public sealed class LambdaNode : SemanticNode
{
    public LambdaNode(NodeMatch match, NodeKind kind) : base(match, kind) { }

    public RedBlock Parameters => Part<RedBlock>(0);
    public RedBlock Body => Part<RedBlock>(2);
}

// 2. Create a definition with pattern
var lambdaDef = Semantic.Define<LambdaNode>("Lambda")
    .Match(p => p.ParenBlock().Operator("=>").BraceBlock())
    .Create((match, kind) => new LambdaNode(match, kind))
    .WithPriority(15)
    .Build();

// 3. Add to schema
var schema = Schema.Create()
    .WithOperators(CommonOperators.JavaScript)
    .Define(lambdaDef)
    .Build();

// 4. Match
var tree = SyntaxTree.Parse("(x) => { return x; }", schema);
var lambdas = tree.Match<LambdaNode>().ToList();

Pattern Builder Matchers

Async Tokenization

// From Stream
await using var stream = File.OpenRead("source.txt");
var tokens = await stream.TokenizeAsync();

// Streaming with IAsyncEnumerable
await foreach (var token in stream.TokenizeStreamingAsync())
{
    Console.WriteLine(token);
}

Also supports PipeReader and custom encoding options.

Error Handling

The tokenizer produces ErrorToken for malformed input and continues parsing:

var tree = SyntaxTree.Parse("}hello{");

// Query for error nodes
var errors = tree.Root.Children
    .Where(n => n.Kind == NodeKind.Error)
    .Cast<RedLeaf>();

foreach (var error in errors)
{
    Console.WriteLine($"Error at {error.Position}: {error.Text}");
}

Benchmarks

Performance comparison of the optimized SearchValues<char> implementation vs the baseline ImmutableHashSet<char>:

Run benchmarks yourself:

dotnet run -c Release --project TinyTokenizer.Benchmarks -- --filter "*"

API Reference

Core Types

// Parse source into syntax tree (recommended)
var tree = SyntaxTree.Parse(source, Schema.Default);

// Low-level tokenization (if needed)
var tokens = source.TokenizeToTokens(options);

// Async streaming from files
await foreach (var token in stream.TokenizeStreamingAsync()) { }

Schema Configuration

// Built-in operator sets
CommonOperators.Universal    // Basic: ==, !=, &&, ||, etc.
CommonOperators.CFamily      // C/C++: ++, --, ->, ::, etc.
CommonOperators.JavaScript   // JS: ===, =>, ?., ??, etc.

// Built-in comment styles
CommentStyle.CStyleSingleLine   // //
CommentStyle.CStyleMultiLine    // /* */
CommentStyle.HashSingleLine     // #

// Create custom schema
var schema = Schema.Create()
    .WithOperators(CommonOperators.JavaScript)
    .WithCommentStyles(CommentStyle.CStyleSingleLine, CommentStyle.CStyleMultiLine)
    .WithTagPrefixes('#', '@')
    .Define(BuiltInDefinitions.FunctionName)
    .Build();

NodeKind Values

Requirements

• .NET 8.0 or later

License

MIT