goawk VS nio

TIL: GoAWK [1] - A POSIX-compliant AWK interpreter written in Go, with CSV support.

[1]: https://github.com/benhoyt/goawk

Another nice project that I have used from time to time (and a very good source for insight) is the awk interpreter written in go https://github.com/benhoyt/goawk

No, I want exactly the opposite - it should be a , b,c as a single string field containing a literal comma, and c. For example, https://github.com/benhoyt/goawk has csv support. https://github.com/benhoyt/goawk/blob/master/docs/csv.md - more info.

I've had a go at solving this in this PR -- feedback welcome. I don't love it, but oh well, it solves the problem at hand. Your comment pointed me in the right direction, thanks again.

There are quite a few re-implementations of scripting languages like Lua in Go. I've written an AWK interpreter in Go.

github.com/benhoyt/goawk -> this library lets you embed an AWK runtime in your applications, very easy to use and useful for enabling some powerful scripting in things you build

Yes, that's right. With my simplistic UTF-8-based implementation it turned length() -- for example -- from O(1) to O(N), turning O(N) algorithms which use length() into O(N^2). See this issue: https://github.com/benhoyt/goawk/issues/93

Similar with substr() and other string functions, which when operating as bytes are O(1), but become O(N) when trying to count the number of codepoints as UTF-8.

GNU Gawk has a fancier approach, which stores strings as UTF-8 as long as it can, but converts to UTF-32 if it needs to (eg: the string is non-ASCII and you call substr).

It looks like Brian Kernighan's code has the same issue with length() and substr(). I'm going to try to email him about this, as I think it's kind of a performance blocker.

I'm not sure if it was via my personal website or just my GitHub profile, but I got my current job at Canonical due to the CTO there reaching out about my GoAWK project (https://github.com/benhoyt/goawk). I get regular recruitment emails because I have my CV/resume online: most of them are very low-effort, but 1 in 20 or something are interesting emails where the recruiter has actually looked at my website and will tailor it personally. I also just enjoy technical writing, and get joy out of sharing it on HN. So it's "worth it" for me.

Sure. No problem.

Even Windows has popen these days. There are some tiny popenr/popenw wrappers in https://github.com/c-blake/cligen/blob/master/cligen/osUt.ni...

Depending upon how balanced work is on either side of the pipe, you usually can even get parallel speed-up on multicore with almost no work. For example, there is no need to use quote-escaped CSV parsing libraries when you just read from a popen()d translator program producing an easier format: https://github.com/c-blake/nio/blob/main/utils/c2tsv.nim

I think it's a pretty nice prog.lang. You may be very happy. Though nothing is perfect, there is much to recommend it. By now I've written over 150 command-line tools with https://github.com/c-blake/cligen . A few are at https://github.com/c-blake/bu or https://github.com/c-blake/nio (screw 1970s COBOL-esque SQL) or in their own repos.

If it helps, I like to use the "mob branch" [0] of TinyCC/tcc [1] for really fast builds in debugging mode, but this may only work if you toss `@if tcc: mm:markAndSweep @end` or similar in your nim.cfg. Then I have a little `@if r: ...` so I can say `nim c -d:r foo` for a release build with gcc/whatever.

[0] https://repo.or.cz/w/tinycc.git

[1] https://en.wikipedia.org/wiki/Tiny_C_Compiler

When you have "format wars", the best idea is usually to have a converter program change to the easiest to work with format - unless this incurs a massive expansion in space as per some image/video formats.

With CSV-like data, bulk conversion from quoted-escaped RFC4180 CSV to a simpler-to-parse format is the best plan for several reasons. First, it may "catch on", help Microsoft/R/whoever embrace the format and in doing so squash many bugs written by "data analyst/scientist coders". Second, in a shell a|b run programs a & b in parallel on multi-core and allow things like csv2x|head -n10000|b. Third, bulk conversion to a random access file where literal delimiters cannot occur as non-delimiters allows trivial file segmentation to be nCores times faster (under often satisfied assumptions). There are some D tools for this in https://github.com/eBay/tsv-utils and a much smaller stand-alone Nim tool https://github.com/c-blake/nio/blob/main/utils/c2tsv.nim . Optional quoting was always going to be a PITA due to its non-locality. What if there is no quote anywhere? Fourth, by using a program as the unit of modularity in this case, you make things programming language agnostic. Someone could go to town and write a pure SIMD/AVX512 converter in assembly even and solve the problem "once and for all" on a given CPU. The problem is actually just simple enough that this smells possible.

I am unaware of any "document" that "standardizes" this escaped/lossless TSV format. { Maybe call it "DSV" for delimiter separated values where "delimiters actually separate"? } Someone want to write an RFC or point to one? It can be just as "general/lossless" (see https://news.ycombinator.com/item?id=31352170).

Of course, if you are going to do a lot of data processing against some data, it is even better to parse all the way to down to binary so that you never have to parse again (Well, unless you call CPUs loading registers "parsing") which is what database systems have been doing since the 1960s.

With https://github.com/c-blake/nio/blob/main/utils/catz.nim you can get similar format agnostic decoding/decompression not just in tar but in any pipeline context (based on magic numbers, not filename extensions and even doing the copy loop needed for unseekable inputs to replace the early read).

Part of the value prop is that you can directly author/access any library code in your native prog.lang in your query as naturally as native imports and routine calls. Awk is pretty established and for trivial one-liners you may not need any libs, but there are a lot more Go/Python/etc. libs than awk libs, AFAICT.

Beyond lib existence there is lib API understanding. There is not only language learning to be saved, but also lib ecosystem learning. I'm sure 'perl -na' folks could rattle off dozens of examples with CPAN package PDQ. I know many people who would say learning the ecosystem is what takes the most time...

There is also little barrier to using the same approach to also "compile" your data as well as the code. This is basically how 'nio qry' works as a kind of open architecture ghetto DB. [1] I mean, yeah, Big Iron, corporate database XYZ probably also has some ugly, non-portable extension language with 1970s prog.lang aesthetics that also sacrifices much value of SQL standardization.

[1] https://github.com/c-blake/nio

I get ~50% the speed of the article's variant with no SIMD at all in https://github.com/c-blake/nio/blob/main/utils/c2tsv.nim

While in Nim, the main logic is really just bout 1 screenful for me and should not be so hard to follow.

As commented elsewhere, but bearing repeating, a better approach is to bulk convert text to binary and then operate off of that. One feature you get is fixed sized rows and thus random access to rows without an index. You can even mmap the file and cast it to a struct pointer if you like (though you need the struct pointer to be the right type). When DBs or DB-ish file formats are faster, being in binary is the 0th order reason why.

The main reason not to do this is if you have no disk space for it.