Stories with Tag DSL

• Writing a DSL in Lua (2015)

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  Posted: 2025-02-21 14:46:13

  Verbose tl;dr

  This 2015 blog post demonstrates how to leverage Lua's flexible syntax and metamechanisms to create a Domain Specific Language (DSL) for generating HTML. The author uses Lua's tables and functions to create a clean, readable syntax that abstracts away the verbosity of raw HTML. By overloading the concatenation operator and utilizing metatables, the DSL allows users to build HTML elements and structures in a declarative way, mirroring the structure of the output. This approach simplifies HTML generation within Lua, making the code cleaner and more maintainable. The post provides concrete examples showing how to define tags, attributes, and nested elements, offering a practical guide to building similar DSLs for other output formats.

  This 2015 blog post by Leaf Corcoran explores the creation of Domain-Specific Languages (DSLs) within Lua, leveraging Lua's flexible syntax and powerful metaprogramming capabilities. Corcoran begins by defining a DSL as a small, specialized language designed for a particular task, contrasting it with general-purpose languages like Lua itself. He argues that DSLs can improve code clarity and conciseness when dealing with specific problem domains by allowing developers to express logic in a manner closer to the problem's natural representation.

  The post then delves into a practical demonstration, building a DSL for generating HTML. Corcoran initially presents a naive approach using string concatenation, highlighting its limitations, particularly regarding code maintainability and error proneness as complexity increases. He then introduces Lua's table-based syntax as a foundation for a more sophisticated DSL. This involves leveraging Lua's metatables and the __index metamethod to dynamically handle function calls and create a fluent, chained syntax for constructing HTML elements.

  The core idea is to represent HTML tags as Lua functions. When a tag function is called, instead of directly executing code, it returns a table. This table has a metatable set up to intercept further function calls or accesses. When another function call is made on the table (representing a nested tag), the __index metamethod intercepts it and creates a new table representing the nested element. This process continues recursively, building a nested structure of tables mirroring the HTML structure.

  The post then details the implementation of an html function, which serves as the entry point for the DSL. This function takes a function as an argument, providing a closure within which the HTML structure can be defined using the DSL’s syntax. The html function manages the process of converting the final nested table structure into a string of valid HTML.

  Furthermore, Corcoran demonstrates how to handle attributes within the DSL. He introduces a special _ function to set attributes on an element. This function takes a table as input, where keys represent attribute names and values represent their corresponding values. This table is then incorporated into the element's table representation.

  Finally, the post briefly touches on handling text content within elements. It suggests a straightforward approach of simply passing strings as arguments to the tag functions. These strings are then stored within the element's table and ultimately incorporated into the final HTML output. The post concludes by highlighting the extensibility of this approach and encouraging readers to explore further enhancements, such as adding support for advanced features like event handling. The presented DSL example serves as a practical starting point for developing more complex and tailored DSLs within Lua for various applications.

  • Lua
  • DSL
  • domain specific language
  • Programming Languages
  • metaprogramming
  • parsing
  • Lexing
  • Code Generation
  • scripting
  • 2015

  Summary of Comments ( 8 )
  https://news.ycombinator.com/item?id=43128021

  Verbose tl;dr

  Hacker News users generally praised the article for its clear explanation of building a DSL in Lua, particularly appreciating the focus on leveraging Lua's existing features and metamechanisms. Several commenters shared their own experiences and preferences for using Lua for DSLs, including its use in game development and configuration management. One commenter pointed out potential performance considerations when using this approach, suggesting that precompilation could mitigate some overhead. Others discussed alternative methods for building DSLs, such as using parser generators. The use of Lua's setfenv was highlighted, with some acknowledging its power while others expressing caution due to potential debugging difficulties. A few users also mentioned other languages like Fennel and Janet as interesting alternatives to Lua for similar purposes.

  The Hacker News post titled "Writing a DSL in Lua (2015)" linking to an article about creating Domain Specific Languages (DSLs) within Lua has generated several comments. Many of the commenters discuss their experiences and perspectives on using Lua for DSLs, and the benefits and drawbacks of this approach.

  One compelling thread discusses the flexibility of Lua and how its lightweight nature and metaprogramming capabilities make it well-suited for creating DSLs quickly. Commenters highlight the power of metatables and how they allow developers to customize the language's behavior, shaping it to fit the specific needs of their DSL. This leads to discussions of real-world applications where Lua DSLs have proven effective, such as game scripting, configuration management, and embedded systems.

  Several comments delve into specific examples of Lua DSLs. One commenter mentions using Lua to create a DSL for configuring networking equipment, while another describes its use in a bioinformatics pipeline. These examples illustrate the practical applicability of Lua for a wide range of problem domains.

  Another point of discussion revolves around the trade-offs between using a full-blown language like Lua for a DSL versus creating a more limited, purpose-built parser. While Lua offers flexibility and existing infrastructure, some commenters argue that a simpler parser can be more performant and easier to maintain for very specific tasks.

  The comments also touch upon the learning curve associated with Lua and its metaprogramming features. While acknowledging the initial investment required to master these concepts, proponents argue that the long-term benefits in terms of expressiveness and code reusability are significant.

  There's also a comparison made between Lua and other languages like Ruby in the context of DSL creation. Some commenters suggest that Ruby's syntax and metaprogramming features are perhaps even more elegant for DSLs, while others maintain that Lua's minimalist approach offers performance advantages.

  Finally, some comments link the discussion to the broader topic of language-oriented programming and the idea of using languages as tools for thought. They highlight how DSLs can empower domain experts to express complex logic in a more natural and intuitive way.

• DSLs for Safe iOS/WatchOS Communication

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  Posted: 2025-02-16 08:02:30

  Verbose tl;dr

  This blog post explores improving type safety and reducing boilerplate when communicating between iOS apps and WatchOS complications using Swift. The author introduces two Domain Specific Languages (DSLs) built with Swift's result builders. The first DSL simplifies defining data models shared between the app and complication, automatically generating the necessary Codable conformance and WatchConnectivity transfer code. The second DSL streamlines updating complications, handling the asynchronous nature of data transfer and providing compile-time checks for supported complication families. By leveraging these DSLs, the author demonstrates a cleaner, safer, and more maintainable approach to iOS/WatchOS communication, minimizing the risk of runtime errors.

  This blog post, titled "DSLs for Safe iOS/WatchOS Communication," explores the challenges and proposes a solution for reliable and type-safe data exchange between an iOS app and its WatchOS counterpart. The author begins by highlighting the inherent difficulties in this inter-device communication, particularly focusing on the fragility of string-based message passing. They argue that relying on string identifiers for messages and manually verifying data types introduces a significant risk of runtime errors and crashes due to typos, inconsistencies between sender and receiver, or changes in data structures over time. This manual process is tedious, error-prone, and difficult to maintain, especially as the complexity of the application grows.

  The core of the proposed solution revolves around leveraging the power of Swift's type system and the concept of Domain Specific Languages (DSLs) to create a more robust and safer communication layer. The author advocates for defining a central, shared protocol that outlines all possible messages exchanged between the watch and the phone. This protocol, expressed in Swift code, serves as a single source of truth for the communication contract.

  The blog post then demonstrates how this protocol can be extended with functionality that generates type-safe wrappers for message sending and receiving. This involves creating helper functions that utilize Swift generics and associated types to ensure that only correctly typed data can be sent and received for each defined message type. The system is designed to catch type mismatches and other data inconsistencies at compile time, preventing potential runtime crashes.

  The post illustrates this approach with concrete examples. It showcases how to define message types within the protocol, how to construct messages on the sending side with type safety guarantees, and how to handle incoming messages on the receiving side with automatic type validation. The author also emphasizes how this method simplifies the overall communication logic, making the code cleaner, more readable, and easier to maintain. Furthermore, the DSL approach allows for effortless addition of new message types without compromising type safety.

  The described method aims to eliminate the need for string-based message identifiers and manual data type checking, significantly reducing the possibility of communication-related errors. This leads to a more reliable and robust interaction between the iOS app and its WatchOS extension, improving the overall user experience. The post concludes by suggesting this approach as a best practice for iOS/WatchOS communication, promoting safer and more maintainable code.

  • iOS
  • WatchOS
  • Apple Watch
  • Swift
  • DSL
  • domain specific language
  • Type Safety
  • Communication
  • inter-process communication
  • IPC
  • data transfer
  • mobile development
  • Software Development

  Summary of Comments ( 5 )
  https://news.ycombinator.com/item?id=43066247

  Verbose tl;dr

  HN commenters generally praised the approach outlined in the article for its type safety and potential to reduce bugs in iOS/WatchOS communication. Some expressed concern about the verbosity of the generated code and suggested exploring alternative approaches like protobuf or gRPC, while acknowledging their added complexity. Others questioned the necessity of a DSL for this specific problem, suggesting that Swift's existing features might suffice with careful design. The potential benefits for larger teams and complex projects were also highlighted, where the enforced type safety could prevent subtle communication errors. One commenter pointed out the similarity to Apache Thrift. Several users appreciated the author's clear explanation and practical example.

  The Hacker News post titled "DSLs for Safe iOS/WatchOS Communication" linking to an article about type-safe WatchOS communication has a modest number of comments, generating a brief discussion around the topic. Several users express appreciation for the approach outlined in the article, highlighting the benefits of type safety and compile-time checks in preventing errors when communicating between an iPhone app and its WatchOS counterpart.

  One commenter points out the inherent complexity and verbosity often associated with WatchOS communication, suggesting that the DSL approach could significantly streamline the process and make it less error-prone. They emphasize that catching these types of errors at compile time is much more efficient and less disruptive than dealing with them during runtime.

  Another comment builds on this by noting the frequent issues encountered with mismatched data types or message formats between the watch and phone, further reinforcing the value proposition of a type-safe solution. This commenter also subtly implies that existing solutions may not adequately address this problem.

  A different commenter focuses on the elegance of using Swift's features to create a DSL. They praise how the approach leverages the language's capabilities to improve developer experience and code clarity.

  There's a short thread discussing alternative approaches, including one suggesting the use of a shared library and another mentioning Google Protobuf and gRPC. While these suggestions are presented, they don't receive much engagement or further discussion.

  Finally, a comment mentions the historical challenges and complexities of watch development, agreeing with the original premise of the article. This commenter expresses a positive outlook toward the proposed DSL as a potential improvement in this area.

  Overall, the comments generally agree with the article's premise and express positive sentiment towards the use of DSLs for safer inter-device communication. While alternative approaches are briefly mentioned, the primary focus remains on the benefits of compile-time safety and improved developer experience afforded by the DSL. The discussion, while not extensive, provides valuable insights and perspectives on the challenges and potential solutions in this domain.

• Residential Networking over Telephone

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  Posted: 2025-02-09 23:54:20

  Verbose tl;dr

  The blog post explores the feasibility and potential advantages of using existing telephone wiring (specifically the unused pairs in twisted-pair copper lines) for home networking. It highlights POTS's robust infrastructure and broad availability, even in areas lacking cable or fiber internet. The author discusses various modulation techniques like G.hn that could deliver speeds comparable to or exceeding current home network technologies while potentially offering better security and interference resistance than Wi-Fi. They also acknowledge challenges such as distance limitations, potential crosstalk with active phone lines (if present), and the need for new hardware. Overall, the post suggests that repurposing telephone wiring could be a viable and even superior alternative to traditional home networking methods.

  This blog post, titled "Residential Networking over Telephone," explores the intriguing, albeit somewhat anachronistic, concept of utilizing existing telephone lines within a residence for networking purposes, as opposed to more conventional methods like Ethernet or Wi-Fi. The author posits that the pre-existing infrastructure of telephone wiring, often neglected in modern homes, presents a unique opportunity for creating a robust and potentially isolated local area network. This network could be particularly advantageous for applications requiring enhanced security or interference immunity, characteristics that the author argues are lacking in contemporary wireless solutions.

  The post delves into the technical specifics of this approach, elucidating the utilization of devices known as "HomePNA" (Home Phone-line Networking Alliance) adapters. These adapters facilitate the transmission of data over the existing telephone wiring, effectively transforming the conventional telephone network into a conduit for digital information exchange within the home. The author meticulously details the process of acquiring and installing these adapters, emphasizing the simplicity of setup and the minimal disruption to existing telephone services. This ease of integration is presented as a key benefit, contrasting with the perceived complexity of installing new cabling for Ethernet networks.

  Furthermore, the article underscores the potential bandwidth capabilities of this technology, noting that certain HomePNA standards can achieve speeds comparable to, or even exceeding, those of older Wi-Fi standards. This performance, the author suggests, makes HomePNA a viable alternative for activities such as streaming media or online gaming, particularly in environments where Wi-Fi signals are weak or unreliable. The author also highlights the inherent security advantages of a wired network like HomePNA, suggesting that its physical isolation provides a greater level of protection against unauthorized access compared to the inherent broadcast nature of wireless technologies.

  Finally, the post concludes with a contemplative observation on the cyclical nature of technology, highlighting how older infrastructure, often dismissed as obsolete, can be repurposed and find new relevance in a modern context. The author paints a picture of HomePNA not as a mere technological curiosity, but as a pragmatic and potentially advantageous solution for certain niche networking requirements within the home environment. The overall tone suggests a blend of practical instruction with a hint of nostalgic appreciation for the resilience and adaptability of older technologies.

  • Residential Networking
  • Telephone Lines
  • Home Networking
  • Data over Telephone Lines
  • Networking Protocols
  • DSL
  • HomePNA
  • HPNA
  • G.hn
  • Networking Technologies
  • Telecommunications
  • Bandwidth
  • Internet Access
  • Home Automation
  • Digital Subscriber Line

  Summary of Comments ( 14 )
  https://news.ycombinator.com/item?id=42995418

  Verbose tl;dr

  Hacker News users generally found the idea of networking over phone lines intriguing, though impractical in most modern contexts. Several commenters discussed the technical details, pointing out limitations in bandwidth and the potential interference issues with existing phone services like DSL. Some reminisced about earlier phone networking attempts, including using BBS systems and dedicated phone-line networking hardware. The consensus was that while the technical challenge is interesting, existing solutions like Ethernet and WiFi are far superior for most residential networking needs, making this approach a novelty rather than a practical solution. A few users pointed out niche use cases, such as situations where running new cables is impossible or extremely difficult, suggesting a very limited potential application.

  The Hacker News post titled "Residential Networking over Telephone" (linking to computer.rip/2025-02-02-residential-networking-over-telephone.html) has generated a modest number of comments, enough to provide some discussion but not an overwhelmingly large thread.

  Several commenters focus on practical aspects and limitations of using phone lines for networking. One points out the significantly lower bandwidth compared to modern technologies like cable or fiber, highlighting that phone lines were designed for voice, not data transmission. This commenter also mentions the difficulty of running higher frequencies over longer distances due to signal attenuation.

  Another commenter questions the practicality of using existing phone wiring for networking, given its often poor quality and the challenges of impedance matching. They suggest that running new, dedicated cabling would likely be a more reliable and efficient approach, even if more labor-intensive.

  There's a discussion about the feasibility of using existing telephone infrastructure for last-mile connectivity in underserved areas. One commenter notes that while the speeds achievable over phone lines might not be comparable to modern broadband, it could still be a significant improvement over nothing, particularly in rural areas lacking other options. This sparks a brief debate about the cost-effectiveness of such an approach compared to investing in other technologies like wireless or satellite internet.

  A few commenters express nostalgia for older technologies like dial-up and BBSes, reminiscing about the days when phone lines were the primary means of internet access. These comments tend to be anecdotal and less focused on the technical aspects of the article's proposal.

  One technically-inclined comment delves into the specifics of DSL technology, explaining how it utilizes higher frequencies to achieve higher data rates. They also mention the limitations imposed by distance and the quality of the copper wiring.

  Finally, a commenter touches on the potential security implications of using phone lines for networking, highlighting the vulnerability to wiretapping and the importance of encryption.

  Overall, the comments offer a mix of practical considerations, technical insights, and nostalgic reflections on the use of phone lines for data communication. While there's some interest in the possibility of using this existing infrastructure, many commenters remain skeptical about its practicality and effectiveness compared to more modern technologies. The discussion highlights the trade-offs between cost, bandwidth, and accessibility in the context of providing internet access, especially in underserved areas.

• Ohm: A user-friendly parsing toolkit for JavaScript and TypeScript

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  Posted: 2025-02-08 13:15:26

  Verbose tl;dr

  Ohm is a parsing toolkit designed for creating parsers in JavaScript and TypeScript that are both powerful and easy to use. It features a grammar definition syntax closely resembling EBNF, enabling developers to express complex syntax rules clearly and concisely. Ohm's built-in support for semantic actions allows users to directly embed JavaScript or TypeScript code within their grammar rules, simplifying the process of building abstract syntax trees (ASTs) and performing other actions during parsing. The toolkit provides excellent error reporting capabilities, helping developers quickly identify and fix syntax errors. Its flexible architecture makes it suitable for various applications, from validating user input to building full-fledged compilers and interpreters.

  Ohm is presented as a parsing toolkit designed for ease of use within JavaScript and TypeScript environments. It aims to simplify the often complex task of creating parsers, tools which analyze and interpret the structure of text according to specific grammatical rules. Ohm achieves this through a grammar definition language that is intended to be more readable and intuitive than traditional regular expressions or other parsing mechanisms. This grammar language allows developers to define the syntax of their target language in a clear and concise manner, closely mirroring the way the language is naturally structured.

  A key feature of Ohm is its focus on producing Abstract Syntax Trees (ASTs), structured representations of the parsed input. These ASTs facilitate further processing and manipulation of the parsed data, making it easier to extract meaning and perform operations on it. Ohm’s ASTs are designed to be easily traversable and manipulated using JavaScript, streamlining the integration of parsing into broader application logic.

  The toolkit provides built-in support for error handling and reporting. When a parsing error occurs, Ohm pinpoints the location of the error within the input and provides helpful diagnostic information. This assists developers in debugging their grammars and identifying issues in the input text quickly. Furthermore, Ohm offers the capability to customize error messages, allowing developers to tailor the feedback to their specific application needs.

  Ohm emphasizes a modular design, enabling the creation of reusable grammar components. This modularity promotes maintainability and reduces code duplication when working with complex grammars. It also simplifies the process of extending existing grammars to support new language features or variations.

  The website highlights Ohm’s use in diverse applications, including building domain-specific languages, creating interactive editors and code formatters, and implementing static analysis tools. This breadth of application showcases its versatility and suitability for various parsing tasks. Furthermore, the site provides extensive documentation, examples, and an interactive editor to facilitate learning and experimentation with the toolkit, contributing to its user-friendly nature. The interactive editor allows users to experiment with grammars and observe the resulting parse trees in real-time, providing a hands-on learning experience. This focus on practical application and accessible resources underscores Ohm’s commitment to simplifying the parsing process for developers.

  • javascript
  • TypeScript
  • parsing
  • parser
  • Toolkit
  • Ohm
  • grammar
  • language design
  • Programming Languages
  • compiler construction
  • DSL
  • domain specific language
  • PEG
  • Parsing Expression Grammar

  Summary of Comments ( 4 )
  https://news.ycombinator.com/item?id=42982755

  Verbose tl;dr

  HN users generally expressed interest in Ohm, praising its user-friendliness, clear documentation, and the power offered by its grammar-based approach to parsing. Several compared it favorably to traditional parser generators like PEG.js and nearley, highlighting Ohm's superior error messages and easier learning curve. Some users discussed potential applications, including building linters, formatters, and domain-specific languages. A few questioned the performance implications of its JavaScript implementation, while others suggested potential improvements like adding support for left-recursive grammars. The overall sentiment leaned positive, with many eager to try Ohm in their own projects.

  The Hacker News thread for "Ohm: A user-friendly parsing toolkit for JavaScript and TypeScript" contains several interesting comments discussing the library's merits, comparisons to other parsing tools, and potential use cases.

  Several commenters praise Ohm's ease of use and intuitive syntax. One user highlights its user-friendliness, contrasting it with the perceived complexity of traditional parser generators like PEG.js and nearley. They specifically appreciate the clear error messages, which are often a pain point when working with parsers. Another commenter echoes this sentiment, emphasizing how Ohm allows them to "think about the grammar" rather than getting bogged down in implementation details. This resonates with another user who describes Ohm as feeling more declarative than other parser generators.

  The discussion also delves into practical applications of Ohm. One commenter mentions using it for parsing custom configuration files, praising its ability to handle complex syntax with relative ease. Another suggests its potential for creating domain-specific languages (DSLs), a task often simplified by tools like Ohm. One user even shares a personal anecdote of using Ohm for a "toy language," highlighting its accessibility for experimentation and learning.

  Comparisons to other parsing tools are inevitable. One commenter draws a parallel to ANTLR, a powerful but more complex parsing tool, suggesting Ohm might be a better choice for smaller projects or those requiring a gentler learning curve. The discussion also touches on the performance aspects of Ohm, with one commenter inquiring about its speed relative to other JavaScript parsers. Another commenter brings up the topic of left recursion, a common parsing challenge, and inquires about Ohm's ability to handle it.

  Some commenters express interest in the educational aspects of Ohm. One user mentions its potential for teaching parsing concepts, appreciating its clear syntax and focus on grammar rules. Another suggests its suitability for beginners, contrasting it with the steeper learning curve associated with other parsing technologies.

  Finally, a few comments touch upon the project's maturity and community. One user expresses curiosity about the size of the Ohm community, while another inquires about the long-term maintenance and support of the project.

• Decorator JITs: Python as a DSL

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  Posted: 2025-02-03 15:03:36

  Verbose tl;dr

  This blog post explores using Python decorators as a foundation for creating just-in-time (JIT) compilers. The author demonstrates this concept by building a simple JIT for a subset of Python, focusing on numerical computations. The approach uses decorators to mark functions for JIT compilation, leveraging Python's introspection capabilities to analyze the decorated function's Abstract Syntax Tree (AST). This allows the JIT to generate optimized machine code at runtime, replacing the original Python function. The post showcases how this technique can significantly improve performance for computationally intensive tasks while still maintaining the flexibility and expressiveness of Python. The example demonstrates transforming simple arithmetic operations into optimized machine code using LLVM, effectively turning Python into a domain-specific language (DSL) for numerical computation.

  Eli Bendersky's blog post, "Decorator JITs: Python as a DSL," explores the concept of using Python's dynamic nature, specifically decorators, to create a just-in-time (JIT) compilation system for a specialized domain-specific language (DSL). Bendersky posits that Python's flexibility allows it to serve as a foundation for constructing efficient, tailored DSLs without resorting to external tools or complex infrastructure.

  The core idea revolves around leveraging decorators to mark functions within the Python code that should be JIT-compiled. These decorators act as an interface between the Python interpreter and the underlying JIT compilation mechanism. When the decorated function is called for the first time, the decorator intercepts the call. Instead of directly executing the Python code, the decorator analyzes the function's structure, including its arguments and operations. It then translates this Python code into a more efficient representation, often a lower-level language like C or machine code, optimized for the specific task at hand. This compiled version is subsequently executed, providing performance gains compared to interpreted Python.

  The blog post delves into a concrete example involving matrix operations. Bendersky illustrates how a @jit decorator can be used to transform Python functions operating on matrices into optimized C code. The decorator effectively hides the complexity of code generation and compilation from the user, allowing them to write concise, Pythonic code that gets transparently accelerated.

  The implementation details presented focus on using C as the target language for compilation. The @jit decorator utilizes the ctypes library to interact with compiled C code. It dynamically generates C code strings representing the matrix operations, compiles them using a C compiler, and then loads the resulting shared library. Subsequent calls to the decorated function directly execute the optimized C code through the loaded library.

  Bendersky highlights several advantages of this approach. First, it leverages Python's expressiveness for defining the DSL. Developers can write familiar Python code to describe the domain-specific logic without needing to learn a new language or tool. Second, the JIT compilation provides performance comparable to natively compiled code for the targeted operations. Third, the system remains flexible and extensible, as new functionalities can be added by defining appropriate decorators.

  Finally, the post acknowledges the limitations of this approach, particularly the overhead of compilation during the initial function call. While subsequent calls benefit from the optimized code, the first invocation incurs the cost of code generation, compilation, and library loading. However, the post argues that for computationally intensive tasks within the DSL, the long-term performance gains outweigh this initial overhead. Furthermore, potential optimizations, like caching compiled code, are discussed to mitigate this limitation. In essence, the post presents a compelling case for using Python decorators and JIT compilation as a powerful technique for creating performant and user-friendly DSLs.

  • Python
  • JIT
  • Just-in-time compilation
  • Decorators
  • DSL
  • domain specific language
  • performance
  • optimization
  • Code Generation
  • metaprogramming
  • Dynamic Compilation

  Summary of Comments ( 27 )
  https://news.ycombinator.com/item?id=42918846

  Verbose tl;dr

  HN users generally praised the article for its clear explanation of using decorators for JIT compilation in Python, with several appreciating the author's approach to explaining a complex topic simply. Some commenters discussed alternative approaches to JIT compilation in Python, including using Numba and C extensions. Others pointed out potential drawbacks of the decorator-based approach, such as debugging challenges and the potential for unexpected behavior. One user suggested using a tracing JIT compiler as a possible improvement. Several commenters also shared their own experiences and use cases for JIT compilation in Python, highlighting its value in performance-critical applications.

  The Hacker News post "Decorator JITs: Python as a DSL" has generated a moderate discussion with several insightful comments. Many of the comments revolve around the practicality, performance implications, and alternatives to the decorator-based JIT compilation approach described in the article.

  One commenter points out that achieving substantial performance gains often requires type hints, which partially defeats the purpose of using Python for its dynamic typing and ease of use. They suggest that if type hints are necessary, a statically typed language might be a more appropriate choice from the outset. This raises the question of whether the decorator JIT approach strikes a good balance between performance and the benefits of Python's dynamic nature.

  Another commenter highlights the potential complexity introduced by the decorator JIT approach, particularly when debugging. They express concern about the added layer of abstraction making it more difficult to understand and troubleshoot issues within the code. This echoes a broader sentiment in the comments regarding the trade-off between performance and maintainability.

  The topic of tracing JIT compilers, like PyPy, is also brought up. A commenter questions whether using PyPy would offer a simpler and more effective solution compared to the decorator-based approach. This prompts a discussion about the specific use cases where a decorator JIT might be advantageous, such as when targeting specialized hardware or requiring fine-grained control over the compilation process.

  Several commenters mention Numba as an alternative solution. Numba, a just-in-time compiler specifically designed for numerical computations in Python, is presented as a more mature and robust option for optimizing performance-critical code. This suggests that while the decorator JIT concept is interesting, existing tools like Numba might already provide a more practical solution for many users.

  Finally, a commenter observes that the approach described in the article is similar to how some DSLs are built and then translated into a lower-level language. They argue that this reinforces the idea of Python being used as a DSL, which is the central theme of the original article. This comment highlights the broader implications of the technique beyond just performance optimization, touching upon the potential for using Python as a higher-level language for generating code in other languages.

• Rhai: An embedded scripting language for Rust

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  Posted: 2025-01-17 15:40:17

  Verbose tl;dr

  Rhai is a fast and lightweight scripting language specifically designed for embedding within Rust applications. It boasts a simple, easy-to-learn syntax inspired by JavaScript and Rust, making it accessible for both developers and end-users. Rhai prioritizes performance and safety, leveraging Rust's ownership and borrowing system to prevent data races and other memory-related issues. It offers seamless integration with Rust, allowing direct access to Rust functions and data structures, and supports dynamic typing, custom functions, modules, and even asynchronous operations. Its versatility makes it suitable for a wide range of use cases, from game scripting and configuration to data processing and rapid prototyping.

  Rhai is presented as a fast, lightweight, and embeddable scripting language specifically designed for integration within Rust projects. Its primary goal is to provide a safe and performant scripting solution tailored for game scripting, application scripting, and extension purposes, empowering developers to extend their Rust applications with dynamic functionalities.

  The language boasts a syntax deliberately reminiscent of Rust, promoting familiarity and easing the transition for Rust developers. This design choice reduces the cognitive overhead associated with learning a new language, allowing developers to leverage their existing Rust knowledge when working with Rhai scripts. However, it also simplifies adoption for developers unfamiliar with Rust, offering a relatively straightforward scripting experience.

  Rhai is built with performance in mind. It leverages just-in-time (JIT) compilation powered by the Cranelift code generator, resulting in significantly faster execution speeds compared to interpreted languages. This compilation approach optimizes script execution, contributing to the overall responsiveness and efficiency of the host application. Furthermore, Rhai provides options for both interpreted and ahead-of-time (AOT) compilation modes, offering flexibility depending on the specific performance and deployment requirements.

  Safety is a paramount concern in Rhai's design. The language operates within a sandboxed environment, effectively isolating scripts from the core Rust application and mitigating potential security risks. This sandboxing mechanism prevents malicious or errant scripts from compromising the stability and integrity of the host application. Custom sandboxing controls can be implemented to fine-tune script access to resources and functionalities.

  Embeddability is a key feature of Rhai. The language is designed for seamless integration within Rust projects. It offers a simple and intuitive API for interacting with Rust code, allowing developers to effortlessly expose Rust functions and data structures to Rhai scripts. This bidirectional interoperability empowers developers to extend their Rust applications with dynamic scripting capabilities, providing a powerful tool for customizing behavior and adapting to evolving needs.

  Rhai is advertised as a versatile solution suitable for a broad range of applications. Its speed, safety, and embeddability make it a compelling choice for game scripting, where performance and dynamic behavior are essential. It's also apt for application scripting, enabling developers to extend and customize application functionality through scripting. The language further finds utility as a generic scripting engine within Rust projects, providing a flexible mechanism for configuration and automation.

  The project is actively maintained and open source, fostering community involvement and continuous improvement. It boasts comprehensive documentation and examples, further simplifying the integration process and enabling developers to quickly get started with Rhai scripting within their Rust projects.

  • rhai
  • Rust
  • scripting language
  • embedded scripting
  • programming language
  • game scripting
  • extension language
  • DSL
  • domain specific language
  • performance
  • Security
  • easy to use
  • ergonomics

  Summary of Comments ( 51 )
  https://news.ycombinator.com/item?id=42738753

  Verbose tl;dr

  HN commenters generally praised Rhai for its speed, ease of embedding, and Rust integration. Several users compared it favorably to Lua, citing better performance and a more "Rusty" feel. Some appreciated its dynamic typing and scripting-oriented nature, while others suggested potential improvements like static typing or a WASM target. The discussion touched on use cases like game scripting, configuration, and embedded systems, highlighting Rhai's versatility. A few users expressed interest in contributing to the project. Concerns raised included the potential performance impact of dynamic typing and the relatively small community size compared to more established scripting languages.

  The Hacker News post titled "Rhai: An embedded scripting language for Rust" has generated a number of comments discussing various aspects of the Rhai scripting language and its integration with Rust.

  Several commenters praised Rhai for its ease of use and embedding within Rust applications. One user appreciated its simplicity and expressiveness, noting how straightforward it was to integrate and use compared to other scripting options. Another commenter highlighted its speed, mentioning its performance is "pretty good" for their use cases involving game scripting. A different user pointed out the benefit of its small size, making it suitable for embedding in resource-constrained environments. The ability to easily expose Rust functions to Rhai was also mentioned favorably by a commenter who found it intuitive and convenient.

  The discussion also touched upon Rhai's features and design choices. One comment explored the decision to use dynamic typing, acknowledging the trade-offs between performance and flexibility. Another commenter inquired about the language's garbage collection mechanism, prompting a response from the creator of Rhai explaining its use of a mark-and-sweep garbage collector. The topic of sandboxing and security was raised, with one commenter asking about mechanisms to prevent malicious scripts from accessing sensitive resources. The project's creator replied, explaining the sandboxing capabilities available within Rhai, including limiting access to external functions and controlling resource usage.

  Comparisons were drawn to other scripting languages like Lua and JavaScript. One commenter discussed the potential advantages of Rhai over Lua for embedding in Rust, specifically mentioning tighter integration and the avoidance of FFI overhead. Another user mentioned their prior experience using JavaScript for scripting and how Rhai provided a simpler and more efficient alternative.

  Finally, some comments focused on the practical applications of Rhai. One user described using it for game scripting, highlighting its performance and ease of use. Another user envisioned using it for configuration and automation tasks. A different commenter expressed interest in exploring Rhai for embedded systems programming.

  Overall, the comments on Hacker News reflect a positive reception of Rhai, with users appreciating its ease of use, performance, and tight integration with Rust. The discussion also delved into more technical details, covering topics such as dynamic typing, garbage collection, sandboxing, and comparisons to other scripting languages. The comments demonstrate the potential of Rhai for a variety of applications, ranging from game scripting to configuration management and embedded systems programming.