A cat­a­log of sup­port for dec­i­mal num­bers in var­i­ous pro­gram­ming lan­guages

Dec­i­mals num­bers are a data type that aims to ex­act­ly rep­re­sent dec­i­mal num­bers. Some pro­gram­mers may not know, or ful­ly re­al­ize, that, in most pro­gram­ming lan­guages, the num­bers that you en­ter look like dec­i­mal num­bers but in­ter­nal­ly are rep­re­sent­ed as bi­na­ry—that is, base-2—float­ing-point num­bers. Things that are to­tal­ly sim­ple for us, such as 0.1, sim­ply can­not be rep­re­sent­ed ex­act­ly in bi­na­ry. The dec­i­mal data type—what­ev­er its stripe or fla­vor—aims to rem­e­dy this by giv­ing us a way of rep­re­sent­ing and work­ing with dec­i­mal num­bers, not bi­na­ry ap­prox­i­ma­tions there­of. (Wikipedia has more.)

To help with my work on adding dec­i­mals to JavaScript, I've gone through a list of pop­u­lar pro­gram­ming lan­guages, tak­en from the 2022 Stack­Over­flow de­vel­op­er sur­vey. What fol­lows is a brief sum­ma­ry of where these lan­guages stand re­gard­ing dec­i­mals. The in­ten­tion is to keep things sim­ple. The pur­pose is:

  1. If a lan­guage does have dec­i­mals, say so;
  2. If a lan­guage does not have dec­i­mals, but at least one third-par­ty li­brary ex­ists, men­tion it and link to it. If a dis­cus­sion is un­der­way to add dec­i­mals to the lan­guage, link to that dis­cus­sion.

There is no in­ten­tion to fil­ter out an lan­guage in par­tic­u­lar; I'm just work­ing with a slice of lan­guages found in in the Stack­Over­flow list linked to ear­li­er. If a lan­guage does not have dec­i­mals, there may well be mul­ti­ple third-part dec­i­mal li­braries. I'm not aware of all li­braries, so if I have linked to a mi­nor li­brary and ne­glect to link to a more high-pro­file one, please let me know. More im­por­tant­ly, if I have mis­rep­re­sent­ed the ba­sic fact of whether dec­i­mals ex­ists at all in a lan­guage, send mail.

C

C does not have dec­i­mals. But they're work­ing on it! The C23 stan­dard (as in, 2023) stan­dard pro­pos­es to add new fixed bit-width data types (32, 64, and 128) for these num­bers.

C#

C# has dec­i­mals in its un­der­ly­ing .NET sub­sys­tem. (For the same rea­son, dec­i­mals also ex­ist in Vi­su­al Ba­sic.)

C++

C++ does not have dec­i­mals. But—like C—they're work­ing on it!

Dart

Dart does not have dec­i­mals. But a third-par­ty li­brary ex­ists.

Go

Go does not have dec­i­mals, but a third-par­ty li­brary ex­ists.

Java

Java has dec­i­mals.

JavaScript

JavaScript does not have dec­i­mals. We're work­ing on it!

Kotlin

Kotlin does not have dec­i­mals. But, in a way, it does: since Kotlin is run­ning on the JVM, one can get dec­i­mals by us­ing Java's built-in sup­port.

PHP

PHP does not have dec­i­mals. An ex­ten­sion ex­ists and at least one third-par­ty li­brary ex­ists.

Python

Python has dec­i­mals.

Ruby

Ruby has dec­i­mals. De­spite that, there is some third-par­ty work to im­prove the built-in sup­port.

Rust

Rust does not have dec­i­mals, but a crate ex­ists.

SQL

SQL has dec­i­mals (it is the DEC­I­MAL data type). (Here is the doc­u­men­ta­tion for, e.g., Post­greSQL, and here is the doc­u­men­ta­tion for MySQL.)

Swift

Swift has dec­i­mals

Type­Script

Type­Script does not have dec­i­mals. How­ev­er, if dec­i­mals get added to JavaScript (see above), Type­Script will prob­a­bly in­her­it dec­i­mals, even­tu­al­ly.