From: "jzakiya (Jabari Zakiya) via ruby-core" <ruby-core@ml.ruby-lang.org>
To: ruby-core@ml.ruby-lang.org
Cc: "jzakiya (Jabari Zakiya)" <noreply@ruby-lang.org>
Subject: [ruby-core:117400] [Ruby master Feature#20404] `2pi`
Date: Mon, 01 Apr 2024 16:00:42 +0000 (UTC) [thread overview]
Message-ID: <redmine.journal-107560.20240401160042.18@ruby-lang.org> (raw)
In-Reply-To: redmine.issue-20404.20240331165144.18@ruby-lang.org
Issue #20404 has been updated by jzakiya (Jabari Zakiya).
This has been brought up before to add the constant `tau`
https://bugs.ruby-lang.org/issues/17496
----------------------------------------
Feature #20404: `2pi`
https://bugs.ruby-lang.org/issues/20404#change-107560
* Author: mame (Yusuke Endoh)
* Status: Open
----------------------------------------
I propose a new Float literal: `2pi`.
```ruby
p 2pi #=> 6.283185307179586 == 2 * Math::PI
```
I am not proposing `1pi`, `3pi` or `4pi`. I do only `2pi`. Because in most cases, all you need is `2pi`. Any other multiple of pi is rarely needed.
I've got the statistics. GitHub code search revealed that more than 80% of the occurrences of `n * Math::PI` and `Math::PI * n` had n = 2. [1]
| n |`n * Math::PI`|`Math::PI * n`|sum | % |
|--:|-------------:|-------------:|----:|---:|
| 0 | 48| 1| 49|1.4%|
| 1 | 58| 3| 61|1.7%|
| 2 | 2300| 534| 2834|80.4%|
| 3 | 218| 17| 235|6.7%|
| 4 | 200| 23| 223|6.3%|
| 5 | 24| 2| 26|0.7%|
| 6 | 41| 3| 44|1.2%|
| 7 | 14| 0| 14|0.4%|
| 8 | 6| 2| 8|0.2%|
| 9 | 8| 0| 8|0.2%|
|10 | 17| 0| 17|0.5%|
|11 | 2| 0| 2|0.1%|
|12 | 2| 0| 2|0.1%|
Here is the PIe chart
![](https://gist.github.com/assets/21557/1c077af3-f753-4ee1-bc75-5b38a3bd6487)
I know that a new constant name "Tau" is proposed (#4897, #17496). But notice: "2pi" and "Tau" have the same number of characters. Then, it is obvious that familiarity is better. In fact, `2 * Math::PI` is 4 times more than `Math::PI * 2`, indicating that all programmers are copying "2pi" in their textbook.
The idea of 2pi came up regularly in chats among committers. The discussion quickly shifted to its generalization: should we treat `3e` as `3 * Math::E`, or even `42foo` as `42 * foo`? However, I noticed such a generalization is unnecessary because all we need is 2pi. Unneeded generalization is evil.
Here is a patch.
```diff
diff --git a/parse.y b/parse.y
index 55619273b8..93b16a16ac 100644
--- a/parse.y
+++ b/parse.y
@@ -10208,6 +10208,13 @@ parse_numeric(struct parser_params *p, int c)
return set_number_literal(p, tINTEGER, suffix, 10, 0);
}
}
+ else if (c == '2' && peek(p, 'p') && peek_n(p, 'i', 1)) {
+ tokadd(p, c);
+ tokadd(p, nextc(p));
+ tokadd(p, nextc(p));
+ tokfix(p);
+ return set_number_literal(p, tFLOAT, 0, 0, 0);
+ }
for (;;) {
switch (c) {
diff --git a/ruby_parser.c b/ruby_parser.c
index 6d85a72c5b..3a6e0b5704 100644
--- a/ruby_parser.c
+++ b/ruby_parser.c
@@ -936,6 +936,9 @@ VALUE
rb_node_float_literal_val(const NODE *n)
{
const rb_node_float_t *node = RNODE_FLOAT(n);
+ if (strcmp(node->val, "2pi") == 0) {
+ return DBL2NUM(2 * M_PI);
+ }
double d = strtod(node->val, 0);
if (node->minus) {
d = -d;
P I
Happy a r l fool
```
[1] I used these queries: [`/[^.]\b2 ?\* ?Math::PI/ language:Ruby`](https://github.com/search?type=code&q=%2F%5B%5E.%5D%5Cb2+%3F%5C*+%3FMath%3A%3API%2F+language%3ARuby) and [`/Math::PI *\* *2\b *[^.\/]/ language:Ruby`](https://github.com/search?type=code&q=%2FMath%3A%3API+*%5C*+*2%5Cb+*%5B%5E.%5C%2F%5D%2F+language%3ARuby)
--
https://bugs.ruby-lang.org/
______________________________________________
ruby-core mailing list -- ruby-core@ml.ruby-lang.org
To unsubscribe send an email to ruby-core-leave@ml.ruby-lang.org
ruby-core info -- https://ml.ruby-lang.org/mailman3/postorius/lists/ruby-core.ml.ruby-lang.org/
next prev parent reply other threads:[~2024-04-01 16:00 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-31 16:51 [ruby-core:117390] [Ruby master Feature#20404] `2pi` mame (Yusuke Endoh) via ruby-core
2024-04-01 5:40 ` [ruby-core:117393] " duerst via ruby-core
2024-04-01 11:24 ` [ruby-core:117397] " byroot (Jean Boussier) via ruby-core
2024-04-01 14:26 ` [ruby-core:117399] " shan (Shannon Skipper) via ruby-core
2024-04-01 16:00 ` jzakiya (Jabari Zakiya) via ruby-core [this message]
2024-04-03 1:16 ` [ruby-core:117409] " mame (Yusuke Endoh) via ruby-core
2024-04-03 6:35 ` [ruby-core:117422] " zverok (Victor Shepelev) via ruby-core
2024-04-03 7:04 ` [ruby-core:117423] " duerst via ruby-core
2024-04-09 3:30 ` [ruby-core:117468] " nobu (Nobuyoshi Nakada) via ruby-core
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-list from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
List information: https://www.ruby-lang.org/en/community/mailing-lists/
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=redmine.journal-107560.20240401160042.18@ruby-lang.org \
--to=ruby-core@ruby-lang.org \
--cc=noreply@ruby-lang.org \
--cc=ruby-core@ml.ruby-lang.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).