V8 VS Duktape

Looks like these are the two commits, based on the issue number:

https://github.com/v8/v8/commit/0981e91a4f8692af337e2588562a...

https://github.com/v8/v8/commit/a2cae2180a7a6d64ccdede44d730...

Although there could be others.

https://github.com/v8/v8/blob/master/src/objects/dictionary.h https://wiki.cdot.senecacollege.ca/wiki/Inline_Assembly_Language https://en.cppreference.com/w/c/language/asm https://en.wikipedia.org/wiki/Inline_assembler https://stackoverflow.com/questions/2268562/what-are-intrinsics https://www.codeproject.com/Articles/15971/Using-Inline-Assembly-in-C-C https://stackoverflow.com/questions/48518225/what-are-intrinsic-types-in-javascript https://stackoverflow.com/questions/12168575/executing-generated-assembler-inline

Many of the languages with much faster implementations and quicker development have literal millions of dollars paying for their progress. I mean, look at the list of authors for V8. That's tens (if not hundreds) of billions of tech heavy weights contributing. Java was painfully slow for the longest time, even with all the money and promotion that Sun put behind it.

Source:

https://github.com/v8/v8/blob/main/src/parsing/scanner.cc#L3...

And also this nice article

https://v8.dev/blog/scanner

"The scanner chooses a specific scanner method or token based on a maximum lookahead of 4 characters, the longest ambiguous sequence of characters in JavaScript"

From what I understand, builtins are coded with v8 torque language in .tq files. However in src/builtins, there is no array-flat.tq file. Then where is it implemented?

It must be a fairly large echo chamber since it has room for Clang, GCC, V8, OpenJDK, Roslyn, etc. (The Zend parser for PHP seems to use some flavor of YACC, but given PHP, I don't know if that strengthens or weakens my point.)

I agree with this, what you may do is pick a large and successful open source c++ project and mimick their structure. Here's the link to Google's V8 javascript engine (core of nodejs/Google chrome js engine) and my logic going forward would be "if it's good enough for a large company and a massive open source community it's probably good enough for me too" https://github.com/v8/v8

Fast math optimizations can break code like this by breaking isNaN.

I was porting a C++ project to a certain platform - and that platform enabled a -ffast-math equivalent by default in Release (but not Debug) builds! This broke duktape, a JS engine said project embedded, in some nasty and subtle ways. Instead of storing a number/pointer/??? (8 bytes) + type tag (4? bytes) for each dynamically typed JS value, duktape can bit-pack values into a single 8 byte "double" value by storing object/string handles as NaN values - this isn't an uncommon trick for dynamically typed scripting stuff:

https://github.com/svaarala/duktape/blob/c3722054ea4a4e50f48...

Naturally, the -ffast-math equivalent broke isNaN checks, which caused random object/string handles to be mistakenly reinterpreted as "numbers" - but only in Release builds, for this one particular platform, in one rarely taken branch, so neither QA nor CI caught it, leading to hours of manufacturing a repro case, stepping through an absurd amount of code, and then finally looking at the default build rules and facepalming.

Cursing the platform vendor under my breath, I overrode the defaults to align with the defaults of every other config x platform combination we already had: no fast math. If you want those optimizations, use SSE-friendly NaN-avoiding intrinsics - or, if you must use the compiler flags, ensure you do so consistently across build configs and platforms, perhaps limited to a few TUs or modules if possible. This allows you to have a chance at using your Debug builds to debug the resulting "optimizations".

Sure. For example, DukTape is an implementation of Javascript designed to be embedded in other projects. Google's V8 Javascript engine (used in Chrome), can also be embedded, see Node.Js for example.

- Duktape (4.8k stars)