format
This library has the goal to bring the Common Lisp format directive to Go. This is work-in-progress, see the summary implementation table below for an overview on what is working and what not.
For a nice introduction to the Common Lisp format see https://en.wikipedia.org/wiki/Format_(Common_Lisp).
Example Code
import "github.com/ragnaroek/format/pkg"
ft.Sformat("~8r", 8) //returns "10"
ft.Sformat("~10,'#,'π₯,2:@X", 4099) //returns "####+10π₯03"
ft.Sformat("~r", 4343637058903381868) //returns "four quintillion three hundred forty-three quadrillion six hundred thirty-seven trillion fifty-eight billion nine hundred three million three hundred eighty-one thousand eight hundred sixty-eight"
ft.Sformat("~:@r", 2799) //returns "MMDCCLXXXXVIIII"
ft.Sformat("~@r", 2799) //returns "MMDCCXCIX"
Playground
Since the format directives can get complicated and the best way to figure them output is to play around with them the format playground was created:
The playground is hosted here: https://ragnaroek.github.io/format/ The library is compiled to WASM to make it run on the browser.
Implementation Status
The directives listed below are already implemented:
| ~ | Name | Prefix args | : | @ | :@ | Note |
|---|---|---|---|---|---|---|
| ~c | Char | Pretty | Escape | :@ not yet implemented | ||
| ~% | Newline | # newline | ||||
| ~& | Freshline | # lines | ||||
~| |
Page | # pages | ||||
| ~~ | Tilde | # ~ | ||||
| ~r | Radix | mincol, padchar, comma-char, comma-interval | Ordinal | Roman | Old Roman | |
| ~d | Decimal | mincol, padchar, comma-char, comma-interval | ||||
| ~b | Binary | mincol, padchar, comma-char, comma-interval | ||||
| ~o | Octal | mincol, padchar, comma-char, comma-interval | ||||
| ~x | Hexadecimal | mincol, padchar, comma-char, comma-interval | ||||
| ~f | Float | width, decimals, scale, overflow, pad | Sign | |||
| ~{ ~} | Iteration | : and @ not yet implemented |
This table is derived from https://www.hexstreamsoft.com/articles/common-lisp-format-reference/clhs-summary/#subsections-summary-table, which was also a great help in the implementation of the directives so far. Many thanks to Jean-Philippe Paradis.
All other directives not mentioned in the table are not implemented yet.
Current work-in-progress
Implementing more directives.
Optimisation! format is currently 16% to 22% times slower than fmt for the standard cases. Currently 47% slower in the float performance.
BenchmarkFmtSimple-12 18412630 59.0 ns/op
BenchmarkFmtLong-12 5016384 235 ns/op
BenchmarkFmtFloat-12 4191775 293 ns/op
BenchmarkFormatSimple-12 17161602 68.5 ns/op
BenchmarkFormatLong-12 4237104 286 ns/op
BenchmarkFormatFloat-12 2731093 429 ns/op
You can run the benchmarks yourself with make bench. A history of benchmark results is collected in BENCHMARK.md.
Thanks
This software is open source (LGPLv3) and was made while listening to a lot of Rage against the Machine βπΏ
