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Metric Teaspoons, Tablespoons & Cups #525

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Metric Teaspoons, Tablespoons & Cups #525

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2bbc60a
feat: add US, metric & aus tsp, tbsp, cups
azyritedev Jun 24, 2025
0389cfd
fix: silence some deprecation warnings from our own code
azyritedev Jun 24, 2025
b6a79b7
fix: base unit is L³ not L, missing cups
azyritedev Jun 24, 2025
266a446
fix: add us cups, deprecation msgs w/o _aus
azyritedev Jun 24, 2025
6c716a8
feat: us_legal vs us_customary cups
azyritedev Jul 6, 2025
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22 changes: 19 additions & 3 deletions src/si/volume.rs
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Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
//! Volume (base unit cubic meter, m³).
#![allow(deprecated)] // rust warns of our own deprecations

quantity! {
/// Volume (base unit cubic meter, m³).
Expand Down Expand Up @@ -63,7 +64,11 @@ quantity! {
@cubic_inch: 1.638_706_E-5; "in³", "cubic inch", "cubic inches";
@cubic_mile: 4.168_182_E9; "mi³", "cubic mile", "cubic miles";
@cubic_yard: 7.645_549_E-1; "yd³", "cubic yard", "cubic yards";
@cup: 2.365_882_E-4; "cup", "cup", "cups";
#[doc = "US cups. Deprecated."]
#[deprecated(note = "please use suffixed unit e.g. _us, _metric")]
@cup: 2.365_882_E-4; "cup (US)", "cup (US)", "cups (US)";
@cup_us: 2.365_882_E-4; "cup (US)", "cup (US)", "cups (US)";
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@OJFord OJFord Jul 4, 2025 •
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This is 'US customary' - there is also 'US legal' (240ml precisely) so it's probably worth being clear what it is even if not also providing the other.

(There's also the old UK imperial system based cup size, I believe it's the same number of floz as US customary cup, but since UK floz != US floz it works out to be about 284ml. It's obsolete though, and I think was never really that common (vs. floz & pints even if they work out to round cups or fractions) so maybe not worth adding.)

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@azyritedev azyritedev Jul 6, 2025

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Alright, thanks for the suggestion.

Modified cup_us to be cup_us_customary and added a cup_us_legal at 240mL, and also changed unit names in 6c716a8

@cup_metric: prefix!(milli) * prefix!(milli) * 250.0; "cup", "cup", "cups";
@fluid_ounce: 2.957_353_E-5; "fl oz", "fluid ounce", "fluid ounces";
@fluid_ounce_imperial: 2.841_306_E-5; "fl oz (UK)", "Imperial fluid ounce", "Imperial fluid ounces";
@gallon_imperial: 4.546_09_E-3; "gal (UK)", "Imperial gallon", "Imperial gallons";
Expand Down Expand Up @@ -97,8 +102,19 @@ quantity! {
@quart_dry: 1.101_221_E-3; "dry qt", "dry quart", "dry quarts";
@quart_liquid: 9.463_529_E-4; "liq qt", "liquid quart", "liquid quarts";
@stere: 1.0_E0; "st", "stere", "steres";
@tablespoon: 1.478_676_E-5; "tbsp", "tablespoon", "tablespoons";
@teaspoon: 4.928_922_E-6; "tsp", "teaspoon", "teaspoons";
#[deprecated(note = "please use suffixed unit e.g. _us, _aus, _metric")]
#[doc = "US tablespoons. Deprecated."] // doc is required here, see macro arms in unit.rs L368 vs L374
@tablespoon: 1.478_676_E-5; "tbsp (US)", "tablespoon (US)", "tablespoons (US)";
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@azyritedev azyritedev Jun 24, 2025

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Unsure what to do with the naming changes ­— technically this could be considered breaking if a library user is relying on matching the abbreviations or names.

However since this is the SI module I assume that the metric units should take priority.

#[deprecated(note = "please use suffixed unit e.g. _us, _metric")]
#[doc = "US teaspoons. Deprecated."]
@teaspoon: 4.928_922_E-6; "tsp (US)", "teaspoon (US)", "teaspoons (US)";
@tablespoon_us: 1.478_676_E-5; "tbsp (US)", "US tablespoon", "US tablespoons";
@teaspoon_us: 4.928_922_E-6; "tsp (US)", "US teaspoon", "US teaspoons";
@tablespoon_metric: prefix!(milli) * prefix!(milli) * 15.0; "tbsp", "tablespoon", "tablespoons";
@teaspoon_metric: prefix!(milli) * prefix!(milli) * 5.0; "tsp", "teaspoon", "teaspoons";
// note: Australian tablespoons are 20mL (so one teaspoon is 1/4 of a tbsp) instead of the
// typical 15mL. There is no difference in the Australian teaspoon.
@tablespoon_aus: prefix!(milli) * prefix!(milli) * 20.0; "tbsp (AU)", "tablespoon (AU)", "tablespoons (AU)";
@register_ton: 2.831_685_E0; "RT", "register ton", "register tons";
}
}
Expand Down