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Nix, the purely functional package manager
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we now keep not a table of all positions, but a table of all origins and their sizes. position indices are now direct pointers into the virtual concatenation of all parsed contents. this slightly reduces memory usage and time spent in the parser, at the cost of not being able to report positions if the total input size exceeds 4GiB. this limit is not unique to nix though, rustc and clang also limit their input to 4GiB (although at least clang refuses to process inputs that are larger, we will not). this new 4GiB limit probably will not cause any problems for quite a while, all of nixpkgs together is less than 100MiB in size and already needs over 700MiB of memory and multiple seconds just to parse. 4GiB worth of input will easily take multiple minutes and over 30GiB of memory without even evaluating anything. if problems *do* arise we can probably recover the old table-based system by adding some tracking to Pos::Origin (or increasing the size of PosIdx outright), but for time being this looks like more complexity than it's worth. since we now need to read the entire input again to determine the line/column of a position we'll make unsafeGetAttrPos slightly lazy: mostly the set it returns is only used to determine the file of origin of an attribute, not its exact location. the thunks do not add measurable runtime overhead. notably this change is necessary to allow changing the parser since apparently nothing supports nix's very idiosyncratic line ending choice of "anything goes", making it very hard to calculate line/column positions in the parser (while byte offsets are very easy). |
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| doc | ||
| m4 | ||
| maintainers | ||
| misc | ||
| mk | ||
| perl | ||
| scripts | ||
| src | ||
| tests | ||
| .clang-format | ||
| .clang-tidy | ||
| .dir-locals.el | ||
| .editorconfig | ||
| .gitignore | ||
| .version | ||
| configure.ac | ||
| CONTRIBUTING.md | ||
| COPYING | ||
| default.nix | ||
| docker.nix | ||
| flake.lock | ||
| flake.nix | ||
| local.mk | ||
| Makefile | ||
| Makefile.config.in | ||
| package.nix | ||
| precompiled-headers.h | ||
| README.md | ||
| shell.nix | ||
Nix
Nix is a powerful package manager for Linux and other Unix systems that makes package management reliable and reproducible. Please refer to the Nix manual for more details.
Installation and first steps
Visit nix.dev for installation instructions and beginner tutorials.
Full reference documentation can be found in the Nix manual.
Building And Developing
See our Hacking guide in our manual for instruction on how to set up a development environment and build Nix from source.
Contributing
Check the contributing guide if you want to get involved with developing Nix.
Additional Resources
License
Nix is released under the LGPL v2.1.