Source code

The source-code category is a syntax-highlighting, linting, and parser fixture set: idiomatic hello-worlds plus realistic snippets across many languages, all original and documented. HTML, CSS, JavaScript, and TypeScript (shipped as .mts to sidestep the MPEG-TS .ts collision) cover the web front-end; Python, Ruby, PHP, and Shell the scripting side; Java, Kotlin, Swift, Go, and Rust the application languages; C and C++ the systems layer; SQL the database; and Wave G adds Julia, Haskell, Lua, R, Clojure, Fortran, and Nim. Intentionally invalid lint fixtures are clearly labelled. A tiny multi-language monorepo ZIP accompanies the set for unpack-then-lint pipelines. Everything text-previewable opens in the in-browser editor.

Filter source code on Browse · 125 files · 31 subcategories

Frequently asked questions

Which languages are included?

Hello-world and realistic snippets across many languages, including C#, Dart, Elixir, Zig, Scala, Julia, Haskell, Lua, R, Clojure, Fortran, and Nim, plus intentionally invalid lint fixtures clearly labelled as such.

Can I edit code samples in the browser?

Yes. Every text-previewable code format is editable and has an editor quick-start preset.

Do you ship a monorepo sample?

Wave G includes a tiny multi-language SAMPLE monorepo ZIP for unpack-then-lint pipelines.

125 of 125 files

C

C Struct

C struct SAMPLE for clangd / highlighter fixtures.

File: C · C
Use case: Syntax highlightingCode parsing+1

C: Hello World

The classic hello-world in C (an include, main, and printf) for testing highlighters, C compilers, and parsers against the canonical first program.

File: C · C
Use case: Syntax highlightingCode parsing+1

C: Linked list (structs, malloc, pointers)

A realistic C program: a singly linked list with a typedef struct, malloc/free memory management, pointer walking, and error handling, for testing highlighters, compilers, and static analysers.

File: C · C
Use case: Syntax highlightingCode parsing+1

Clojure

Clojure Hello

Minimal Clojure hello for CIDER / clj-kondo fixtures.

File: CLJ · Clojure
Use case: Syntax highlightingCode parsing+1

Clojure Reduce

Clojure reduce utility: realistic snippet.

File: CLJ · Clojure
Use case: Syntax highlightingCode parsing+1

Clojure Thread Macro

Clojure thread-first macro for highlighter tests.

File: CLJ · Clojure
Use case: Syntax highlightingCode parsing+1

Clojure: Intentionally Invalid

Intentionally invalid Clojure (unbalanced forms) for clj-kondo-style tests.

File: CLJ · Clojure
Use case: Error handlingCode parsing+1

C++

C++ Optional

C++17 optional SAMPLE for clangd fixtures.

File: CPP · C++ · cpp
Use case: Syntax highlightingCode parsing+1

C++: Hello World

The classic hello-world in C++: iostream and std::cout, for testing highlighters, C++ compilers, and parsers.

File: CPP · C++
Use case: Syntax highlightingCode parsing+1

C++: Series (class template, STL)

A realistic C++ snippet with a class template, STL algorithms (max_element, accumulate), std::move, and range handling, for testing highlighters, g++/clang++, and parsers against real templates.

File: CPP · C++
Use case: Syntax highlightingCode parsing+1

Csharp

C# Fibonacci

A small C# iterator Fibonacci utility: realistic snippet for language tooling.

File: CS · Csharp
Use case: Syntax highlightingCode parsing+1

C# Hello

Idiomatic C# hello-world for syntax highlighters and Roslyn-style parsers.

File: CS · Csharp
Use case: Syntax highlightingCode parsing+1

C# LINQ SAMPLE

C# LINQ chain SAMPLE for Roslyn fixtures.

File: CS · Csharp
Use case: Syntax highlightingCode parsing+1

Csharp Lint Invalid: Empty Catch Invalid

Intentionally lint-bait SAMPLE csharp snippet (empty-catch-invalid) for rule-engine tests.

File: CS · Csharp
Use case: Code parsingSyntax highlighting+1· Conversion set

Css

CSS: Component styles (variables, flexbox, keyframes)

A realistic component stylesheet using custom properties, flexbox, a fluid clamp() font size, color-mix(), a keyframe animation, and a media query, for testing CSS parsers, linters (stylelint), and highlighters.

File: CSS · Css
Use case: Syntax highlightingCode parsing+1

CSS: Hello World

A minimal stylesheet that centres a heading with grid: the simplest useful CSS file for testing highlighters, CSS parsers, and minifiers.

File: CSS · Css
Use case: Syntax highlightingCode parsing+1

Dart

Dart Counter

Tiny Dart class with a counter: fixture for Dart analysis servers.

File: DART · Dart
Use case: Syntax highlightingCode parsing+1

Dart Future

Dart async Future SAMPLE for analysis-server tests.

File: DART · Dart
Use case: Syntax highlightingCode parsing+1

Dart Hello

Minimal Dart hello-world for Flutter/Dart IDE and highlight tests.

File: DART · Dart
Use case: Syntax highlightingCode parsing+1

Elixir

Elixir GenServer Stub

Elixir GenServer stub SAMPLE for Beam tooling.

File: EX · Elixir
Use case: Syntax highlightingCode parsing+1

Elixir Hello

Elixir module hello, for Beam/Elixir syntax and formatter smoke tests.

File: EX · Elixir
Use case: Syntax highlightingCode parsing+1

Elixir Pipeline

Elixir pipe-operator snippet for AST and formatter fixtures.

File: EX · Elixir
Use case: Syntax highlightingCode parsing+1

Fortran

Fortran Hello

Minimal Fortran 90 hello for gfortran / highlighter fixtures.

File: F90 · Fortran
Use case: Syntax highlightingCode parsing+1

Fortran Module

Fortran module with a pure-ish helper for module parsers.

File: F90 · Fortran
Use case: Syntax highlightingCode parsing+1

Fortran Sum

Fortran do-loop sum: realistic numerical snippet.

File: F90 · Fortran
Use case: Syntax highlightingCode parsing+1

Fortran: Intentionally Invalid

Intentionally invalid Fortran for compiler error fixtures.

File: F90 · Fortran
Use case: Error handlingCode parsing+1

Go

Go Generics

Go generics helper for gopls / highlighter fixtures.

File: GO · Go
Use case: Syntax highlightingCode parsing+1

Go Lint Invalid: Errcheck Invalid

Intentionally lint-bait SAMPLE go snippet (errcheck-invalid) for rule-engine tests.

File: GO · Go
Use case: Code parsingSyntax highlighting+1· Conversion set

Go: Hello World

The classic hello-world in Go (package main, an import, and fmt.Println, tab-indented like gofmt) for testing highlighters, the Go compiler, and parsers.

File: GO · Go
Use case: Syntax highlightingCode parsing+1

Go: Intentionally Invalid

Intentionally invalid Go syntax for gofmt/parser failure tests.

File: GO · Go
Use case: Error handlingCode parsing+1

Go: Worker pool (goroutines, channels)

A realistic Go program: a worker pool with structs and methods, goroutines, buffered channels, and a sync.WaitGroup, tab-indented like gofmt, for testing highlighters, go vet, and parsers.

File: GO · Go
Use case: Syntax highlightingCode parsing+1

Haskell

Haskell Fold

Haskell foldl snippet for AST and highlighter tests.

File: HS · Haskell
Use case: Syntax highlightingCode parsing+1

Haskell Hello

Idiomatic Haskell hello-world for GHC / HLS fixtures.

File: HS · Haskell
Use case: Syntax highlightingCode parsing+1

Haskell Maybe

Haskell Maybe pattern matching: realistic small module.

File: HS · Haskell
Use case: Syntax highlightingCode parsing+1

Haskell Typeclass SAMPLE

Haskell Typeclass SAMPLE for Wave G language-tooling coverage.

File: HS · Haskell
Use case: Syntax highlightingCode parsing+1

Haskell: Intentionally Invalid

Intentionally invalid Haskell (unterminated string) for parser failure tests.

File: HS · Haskell
Use case: Error handlingCode parsing+1

HTML

HTML: Hello World

A minimal, valid HTML5 document (doctype, head, and a single heading) for testing HTML parsers, highlighters, and validators against the simplest well-formed page.

File: HTML · HTML
Use case: Syntax highlightingCode parsing+1

HTML: Semantic article page

A realistic semantic HTML page with landmark elements (header, nav, main, article, footer), a figure with alt text and caption, and lists, for testing HTML parsers, accessibility tooling, and highlighters.

File: HTML · HTML
Use case: Syntax highlightingCode parsing+1

Java

Java Lint Invalid: Empty Catch Invalid

Intentionally lint-bait SAMPLE java snippet (empty-catch-invalid) for rule-engine tests.

File: JAVA · Java
Use case: Code parsingSyntax highlighting+1· Conversion set

Java Record

Java record type hello for javac / highlighter fixtures.

File: JAVA · Java
Use case: Syntax highlightingCode parsing+1

Java: Bank account (class, record, exceptions)

A realistic Java class with a package declaration, fields, a nested record, methods that throw exceptions, and formatted output, for testing highlighters, javac, Checkstyle, and parsers.

File: JAVA · Java
Use case: Syntax highlightingCode parsing+1

Java: Hello World

The classic hello-world in Java (a public class with the standard main method) for testing highlighters, javac, and Java parsers.

File: JAVA · Java
Use case: Syntax highlightingCode parsing+1

JavaScript

Code Config: Eslint Flat Snippet

Tiny SAMPLE tooling config snippet (eslint-flat-snippet) for editor/linter harnesses.

File: JS · JavaScript
Use case: Config parsingEditor testing+1· Conversion set

Javascript Lint Invalid: Eqeqeq Invalid

Intentionally lint-bait SAMPLE javascript snippet (eqeqeq-invalid) for rule-engine tests.

File: JS · JavaScript
Use case: Code parsingSyntax highlighting+1· Conversion set

Javascript Lint Invalid: Var Shadow Invalid

Intentionally lint-bait SAMPLE javascript snippet (var-shadow-invalid) for rule-engine tests.

File: JS · JavaScript
Use case: Code parsingSyntax highlighting+1· Conversion set

JavaScript: Hello World

The classic hello-world in modern JavaScript: a minimal function calling console.log, for testing highlighters, Node, and JS parsers.

File: JS · JavaScript
Use case: Syntax highlightingCode parsing+1

JavaScript: Intentionally Invalid Syntax

Intentionally corrupt JavaScript object literal, labelled invalid for error handling. Labelled intentionally invalid in title and description.

File: JS · JavaScript
Use case: Error handlingCode parsing+1

JavaScript: To-do list (class, private fields, async)

A realistic JavaScript snippet with an ES class, private #fields, arrow functions, template literals, a getter, and async/await, for testing highlighters, ESLint, Prettier, and bundlers.

File: JS · JavaScript
Use case: Syntax highlightingCode parsing+1

JSON

Code Config: Prettier Config

Tiny SAMPLE tooling config snippet (prettier-config) for editor/linter harnesses.

File: JSON · JSON
Use case: Config parsingEditor testing+1· Conversion set

Code Config: Tsconfig Strict Snippet

Tiny SAMPLE tooling config snippet (tsconfig-strict-snippet) for editor/linter harnesses.

File: JSON · JSON
Use case: Config parsingEditor testing+1· Conversion set

JSON: Intentionally Invalid (Lint Fixture)

Intentionally invalid JSON (unquoted key + trailing) for strict parser failure tests. Labelled intentionally invalid in title and description.

File: JSON · JSON
Use case: Error handlingCode parsing+1

Julia

Julia Broadcast

Julia broadcast operators (.^ .+ ) for highlighter and parser edge cases.

File: JL · Julia
Use case: Syntax highlightingCode parsing+1

Julia Fibonacci

Julia typed Fibonacci with a for-loop: realistic snippet for language tooling.

File: JL · Julia
Use case: Syntax highlightingCode parsing+1

Julia Hello

Minimal Julia hello-world for syntax highlighters and Julia LSP smoke tests.

File: JL · Julia
Use case: Syntax highlightingCode parsing+1

Julia Macro SAMPLE

Julia Macro SAMPLE for Wave G language-tooling coverage.

File: JL · Julia
Use case: Syntax highlightingCode parsing+1

Julia: Intentionally Invalid

Intentionally invalid Julia (unclosed function) for linter error-path tests.

File: JL · Julia
Use case: Error handlingCode parsing+1

Kotlin

Kotlin Data Class

Kotlin data class SAMPLE for Kotlin language-server tests.

File: KT · Kotlin
Use case: Syntax highlightingCode parsing+1

Kotlin: Hello World

The classic hello-world in Kotlin (a top-level main function) for testing highlighters, the Kotlin compiler, and parsers.

File: KT · Kotlin
Use case: Syntax highlightingCode parsing+1

Kotlin: Order model (data classes, sealed types, when)

A realistic Kotlin snippet with data classes, an enum, a sealed result interface, extension functions, and when expressions, for testing highlighters, the Kotlin compiler, ktlint, and parsers.

File: KT · Kotlin
Use case: Syntax highlightingCode parsing+1

Lua

Lua Coroutine

Tiny Lua coroutine yield loop for language tooling.

File: LUA · Lua
Use case: Syntax highlightingCode parsing+1

Lua Hello

Minimal Lua hello for embedder and syntax-highlight tests.

File: LUA · Lua
Use case: Syntax highlightingCode parsing+1

Lua Metatable SAMPLE

Lua Metatable SAMPLE for Wave G language-tooling coverage.

File: LUA · Lua
Use case: Syntax highlightingCode parsing+1

Lua Table

Lua table with method colon syntax for parsers.

File: LUA · Lua
Use case: Syntax highlightingCode parsing+1

Lua: Intentionally Invalid

Intentionally invalid Lua table for error handling.

File: LUA · Lua
Use case: Error handlingCode parsing+1

Monorepo

Sample Monorepo ZIP: Multi-Language Companion

Tiny multi-language SAMPLE monorepo ZIP (web/api/util/scripts) for unpack-then-lint and monorepo tooling.

File: ZIP · Monorepo · 5 members
Use case: Code parsingConversion testing

Nim

Nim Hello

Minimal Nim hello for nimlsp / highlighter tests.

File: NIM · Nim
Use case: Syntax highlightingCode parsing+1

Nim Object

Nim object type plus proc, for Nim AST tooling.

File: NIM · Nim
Use case: Syntax highlightingCode parsing+1

Nim Proc

Nim recursive fib proc: realistic snippet.

File: NIM · Nim
Use case: Syntax highlightingCode parsing+1

Nim Template SAMPLE

Nim Template SAMPLE for Wave G language-tooling coverage.

File: NIM · Nim
Use case: Syntax highlightingCode parsing+1

Nim: Intentionally Invalid

Intentionally invalid Nim for nim check error paths.

File: NIM · Nim
Use case: Error handlingCode parsing+1

PHP

PHP Attributes

PHP 8 attributes SAMPLE for PHP tooling.

File: PHP · PHP
Use case: Syntax highlightingCode parsing+1

Php Lint Invalid: Error Suppression Invalid

Intentionally lint-bait SAMPLE php snippet (error-suppression-invalid) for rule-engine tests.

File: PHP · PHP
Use case: Code parsingSyntax highlighting+1· Conversion set

PHP: Hello World

The classic hello-world in PHP (an opening tag and echo) for testing highlighters, the PHP interpreter, and parsers.

File: PHP · PHP
Use case: Syntax highlightingCode parsing+1

PHP: Invoice (enum, class, promoted properties)

A realistic modern-PHP snippet with strict types, a namespace, a backed enum, a final class with constructor-promoted readonly properties, and array_reduce with an arrow function, for testing highlighters, PHPStan, and parsers.

File: PHP · PHP
Use case: Syntax highlightingCode parsing+1

Python

Python Async Gather

Tiny asyncio gather stub for async Python tooling.

File: PY · Python
Use case: Syntax highlightingCode parsing+1

Python Dataclass SAMPLE

Python dataclass SAMPLE for highlighter and type-checker smoke tests.

File: PY · Python
Use case: Syntax highlightingCode parsing+1

Python Lint Invalid: Bare Except Invalid

Intentionally lint-bait SAMPLE python snippet (bare-except-invalid) for rule-engine tests.

File: PY · Python
Use case: Code parsingSyntax highlighting+1· Conversion set

Python Lint Invalid: Unused Import Invalid

Intentionally lint-bait SAMPLE python snippet (unused-import-invalid) for rule-engine tests.

File: PY · Python
Use case: Code parsingSyntax highlighting+1· Conversion set

Python: Fibonacci (dataclass, generator, type hints)

A realistic Python snippet exercising type hints, an lru_cache-memoised recursive function, a generator, and a frozen dataclass, for testing syntax highlighters, linters (ruff/flake8), and formatters (black).

File: PY · Python
Use case: Syntax highlightingCode parsing+1

Python: Hello World

The classic hello-world in idiomatic Python 3, with a shebang, a module docstring, and the standard main guard: the minimal correct program for testing highlighters and interpreters.

File: PY · Python
Use case: Syntax highlightingCode parsing+1

Python: Intentionally Invalid Indent

Intentionally invalid Python indentation for linter / parser error-path tests. Labelled intentionally invalid in title and description.

File: PY · Python
Use case: Error handlingCode parsing+1

Python: Intentionally Invalid Match

Intentionally invalid Python match (missing colon) for linters.

File: PY · Python
Use case: Error handlingCode parsing+1

R

R Data Frame

R data.frame construction: realistic snippet for R parsers.

File: R · R
Use case: Syntax highlightingCode parsing+1

R Hello

Minimal R hello-world for RStudio / language-server fixtures.

File: R · R
Use case: Syntax highlightingCode parsing+1

R Pipe

R native pipe (|>) snippet for modern R tooling.

File: R · R
Use case: Syntax highlightingCode parsing+1

R: Intentionally Invalid

Intentionally invalid R (unclosed call) for parser tests.

File: R · R
Use case: Error handlingCode parsing+1

Ruby

Ruby Lint Invalid: Rescue All Invalid

Intentionally lint-bait SAMPLE ruby snippet (rescue-all-invalid) for rule-engine tests.

File: RB · Ruby
Use case: Code parsingSyntax highlighting+1· Conversion set

Ruby Module

Ruby nested module SAMPLE for parser tests.

File: RB · Ruby
Use case: Syntax highlightingCode parsing+1

Ruby: Hello World

The classic hello-world in Ruby (a single puts) for testing highlighters, the Ruby interpreter, and parsers.

File: RB · Ruby
Use case: Syntax highlightingCode parsing+1

Ruby: Stack (Enumerable, blocks, custom error)

A realistic Ruby snippet: a Stack class that mixes in Enumerable, yields blocks, raises a custom error class, and uses string interpolation and symbol-to-proc, for testing highlighters, RuboCop, and parsers.

File: RB · Ruby
Use case: Syntax highlightingCode parsing+1

Rust

Rust Lint Invalid: Unwrap Invalid

Intentionally lint-bait SAMPLE rust snippet (unwrap-invalid) for rule-engine tests.

File: RS · Rust
Use case: Code parsingSyntax highlighting+1· Conversion set

Rust Result Map

Rust Result map chain: realistic error-handling snippet.

File: RS · Rust
Use case: Syntax highlightingCode parsing+1

Rust: Hello World

The classic hello-world in Rust: fn main and the println! macro, for testing highlighters, rustc, and parsers.

File: RS · Rust
Use case: Syntax highlightingCode parsing+1

Rust: Intentionally Invalid

Intentionally invalid Rust for rustc error-path fixtures.

File: RS · Rust
Use case: Error handlingCode parsing+1

Rust: Shapes (enum, trait, pattern matching)

A realistic Rust snippet with an enum carrying data, a trait and impl, exhaustive match, iterators, and Option handling, for testing highlighters, rustc, clippy, and parsers against real ownership-era code.

File: RS · Rust
Use case: Syntax highlightingCode parsing+1

Scala

Scala Fold

Scala foldLeft snippet for syntax and indexer tests.

File: SCALA · Scala
Use case: Syntax highlightingCode parsing+1

Scala Hello

Scala 3-style object hello for Scalac / Metals fixtures.

File: SCALA · Scala
Use case: Syntax highlightingCode parsing+1

Scala Match

Scala pattern match SAMPLE for Metals fixtures.

File: SCALA · Scala
Use case: Syntax highlightingCode parsing+1

Shell

Shell Lint Invalid: Unquoted Var Invalid

Intentionally lint-bait SAMPLE shell snippet (unquoted-var-invalid) for rule-engine tests.

File: SH · Shell
Use case: Code parsingSyntax highlighting+1· Conversion set

Shell Strict Mode

Bash strict-mode hello for shellcheck / highlighter tests.

File: SH · Shell
Use case: Syntax highlightingCode parsing+1

Shell: Backup script (strict mode, functions)

A realistic Bash script using strict mode (set -euo pipefail), functions, default parameters, a loop, and conditionals: an illustrative fixture (review before running) for testing highlighters, ShellCheck, and shfmt.

File: SH · Shell
Use case: Syntax highlightingCode parsing+1

Shell: Hello World

The classic hello-world in Bash (a shebang and echo, with LF line endings so it runs on Unix) for testing highlighters, ShellCheck, and shell parsers.

File: SH · Shell
Use case: Syntax highlightingCode parsing+1

Sql

SQL Lint Shape: Drop Table Comment

Tiny SAMPLE SQL shape (drop-table-comment) for static-analysis demos, not live DDL.

File: SQL · Sql
Use case: Code parsingSQL import+1· Conversion set

SQL Lint Shape: Implicit Cross Join

Tiny SAMPLE SQL shape (implicit-cross-join) for static-analysis demos, not live DDL.

File: SQL · Sql
Use case: Code parsingSQL import+1· Conversion set

SQL Lint Shape: Missing Where Update

Tiny SAMPLE SQL shape (missing-where-update) for static-analysis demos, not live DDL.

File: SQL · Sql
Use case: Code parsingSQL import+1· Conversion set

SQL Lint Shape: Order By Injection Shape

Tiny SAMPLE SQL shape (order-by-injection-shape) for static-analysis demos, not live DDL.

File: SQL · Sql
Use case: Code parsingSQL import+1· Conversion set

SQL Lint Shape: Select Star Invalid

Tiny SAMPLE SQL shape (select-star-invalid) for static-analysis demos, not live DDL.

File: SQL · Sql
Use case: Code parsingSQL import+1· Conversion set

SQL Lint Shape: Union All Dupes

Tiny SAMPLE SQL shape (union-all-dupes) for static-analysis demos, not live DDL.

File: SQL · Sql
Use case: Code parsingSQL import+1· Conversion set

SQL Window Function

SQL window function SAMPLE for SQL parsers.

File: SQL · Sql
Use case: Syntax highlightingCode parsing+1

SQL: Hello World

The classic first query in SQL (a single SELECT of a literal) for testing highlighters, SQL parsers, and query editors.

File: SQL · Sql
Use case: Syntax highlightingCode parsing+1

SQL: Library schema (DDL, view, join)

A realistic SQL script with CREATE TABLE constraints and foreign keys, INSERT seed data, a CREATE VIEW, and a grouped aggregate query with a join, for testing SQL parsers, formatters, and highlighters.

File: SQL · Sql
Use case: Syntax highlightingCode parsing+1

Swift

Swift Struct

Swift struct SAMPLE for SourceKit fixtures.

File: SWIFT · Swift
Use case: Syntax highlightingCode parsing+1

Swift: Hello World

The classic hello-world in Swift (a single print) for testing highlighters, the Swift compiler, and parsers.

File: SWIFT · Swift
Use case: Syntax highlightingCode parsing+1

Swift: Task list (struct, protocol, optionals)

A realistic Swift snippet with an enum, a protocol, a struct with a computed property, optionals and optional binding, and higher-order functions, for testing highlighters, the Swift compiler, SwiftLint, and parsers.

File: SWIFT · Swift
Use case: Syntax highlightingCode parsing+1

TypeScript

Typescript Lint Invalid: Any Cast Invalid

Intentionally lint-bait SAMPLE typescript snippet (any-cast-invalid) for rule-engine tests.

File: MTS · TypeScript
Use case: Code parsingSyntax highlighting+1· Conversion set

TypeScript Satisfies

TypeScript satisfies operator sample (.mts) for TS tooling.

File: MTS · TypeScript
Use case: Syntax highlightingCode parsing+1

TypeScript: Hello World

The classic hello-world in TypeScript (shipped as .mts to avoid the MPEG-TS .ts collision): a typed function for testing TypeScript-aware highlighters and the tsc compiler.

File: MTS · TypeScript
Use case: Syntax highlightingCode parsing+1

TypeScript: Shapes (union, generics, enum)

A realistic TypeScript snippet with an enum, a discriminated union, generics, exhaustive switch handling, and a typed reduce, for testing the type checker, highlighters, and the TS ESLint parser.