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A Lean Syntax Primer — overreacted
2 months ago
- Lean uses `:=` for definitions and `=` for comparisons, with type inference for `String`, `Nat`, `Int`.
- `#eval` runs code and displays results in the InfoView, while `#print` can output to terminal.
- Proofs are written with `theorem` and tactics like `unfold`, `decide`, `simp`, and `omega`.
- Function calls use no parentheses or commas: `f a b c`; parentheses are only for grouping expressions.
- `let` bindings allow local definitions inside functions, and the last expression is the return value.
- Functions can be declared in multiple ways, with explicit or implicit types, including anonymous `fun` syntax.
- The universal quantifier `∀` enables proving statements for all possible values of a parameter.
- Implicit arguments `{ }` and instance arguments `[ ]` are automatically filled by Lean, reducing boilerplate.
- Lean is highly interactive: `Command+Click` on any identifier opens its definition or source.
Beej's Bit Bucket
2 months ago
- This demo explains building a custom drag-and-drop system with JavaScript and CSS, using jQuery for ease while implementing core functionality manually.
- The system moves elements by setting their CSS 'position' to 'absolute' and updating 'left' and 'top' properties relative to the container.
- Drag mode is initiated on mousedown, items follow the mouse during move, and on mouseup, the drop is processed with collision detection on droptargets.
- To avoid the element's corner sticking to the mouse, the system remembers the mouse offset on the element at click and adjusts positioning accordingly.
- Mouse coordinates are converted from document space to the container's coordinate system for proper absolute positioning within the container.
- Elements with class 'stayinparent' are restricted to their parent container, while others can move freely across the document.
- Drop containers are marked with class 'droptarget'; on drop, collisions are checked and a 'drop' event is dispatched with the draggable element.
- Usage involves setting 'draggable' and 'droptarget' classes, calling 'beejdnd.init()', and binding a drop event handler with a draggable reference.
- Suggestions for improvements include bounding drag areas, axis restriction, clone creation, scroll-on-edge, multitouch support, and jQuery plugin conversion.
- The code is licensed under the MIT open source license.
Beej's Bit Bucket
2 months ago
- Virtual environments isolate Python packages, preventing system pollution and conflicts.
- Create a virtual environment with `python -m venv <env-name>`; activate by sourcing `bin/activate`.
- While active, install packages using `pip install`; they are confined to the environment.
- Deactivate with `deactivate` or by exiting the shell; delete the environment directory to remove it.
- Run scripts directly using the venv's Python path (e.g., `/path/to/venv/bin/python script.py`) without activation.
- Third-party tools like `uv` can streamline virtual environment management.
Zig by Example
2 months ago
- Zig is a general-purpose programming language designed for robust, optimal, and reusable software.
- Official documentation is available for further learning.
- Zig by Example is a hands-on introduction using annotated example programs.
- The examples are written for version 0.16; check your version if something isn't working.
WebGPU Unleashed: A Practical Tutorial
2 months ago
- This free book teaches graphics programming in JavaScript using WebGPU, drawing from the author's personal learning journey.
- WebGPU is a new graphics API that wraps Vulkan, Metal, and DirectX 12, making it simpler, cross-platform, and ideal for beginners.
- The tutorial starts with GPU driver and pipeline overviews, then covers drawing triangles, 2D/3D rendering, and advanced GPU computing.
- It includes interactive online features like videos, linked references, a code playground, and reader feedback via GitHub.
- The final tutorial implements Gaussian splatting rendering, a complex technique combining GPU compute and realistic 3D scene rendering.
Vulkan Tutorial
2 months ago
- This Vulkan tutorial from 2016 is outdated; readers are directed to https://vulkan.org/learn for current guides.
- Vulkan provides better abstraction of modern GPUs, leading to better performance and less surprising driver behavior compared to OpenGL and Direct3D.
- Vulkan is cross-platform (Windows, Linux, Android) but requires verbose API setup; it targets programmers enthusiastic about high-performance graphics.
- Prerequisites include a Vulkan-compatible GPU, C++17 experience, and basic 3D computer graphics knowledge.
- The tutorial uses the original C API and covers setting up Vulkan SDK, GLM, and GLFW; each chapter builds toward rendering a triangle.
- Future chapters expand to linear transformations, textures, and 3D models; the tutorial is community-driven with feedback via GitHub.
Otary – Image and Geometry Python Library Now Has Tutorials
3 months ago
- Provides examples of using Otary for understanding its functionality.
- Covers topics like image cropping, linear entities, scoring, area computation, geometric intersections, and OCR.
- Aims to inspire exploration and practical application rather than serve as a complete reference.

tutorial

A Lean Syntax Primer — overreacted

Beej's Bit Bucket

Beej's Bit Bucket

Zig by Example

WebGPU Unleashed: A Practical Tutorial

Vulkan Tutorial

Otary – Image and Geometry Python Library Now Has Tutorials