fix: make formattime follow system locale (#1177)

closes #869

Co-authored-by: CrumblyLiquid <crumblyliquid@gmail.com>

Cargo.lock

@@ -485,6 +485,7 @@ dependencies = [
  "iana-time-zone",
  "js-sys",
  "num-traits",
+ "pure-rust-locales",
  "wasm-bindgen",
  "windows-targets 0.52.6",
 ]
@@ -975,6 +976,7 @@ dependencies = [
 name = "eww_shared_util"
 version = "0.1.0"
 dependencies = [
+ "chrono",
  "derive_more",
  "ref-cast",
  "serde",
@@ -2238,6 +2240,12 @@ dependencies = [
  "unicode-ident",
 ]
 
+[[package]]
+name = "pure-rust-locales"
+version = "0.8.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1190fd18ae6ce9e137184f207593877e70f39b015040156b1e05081cdfe3733a"
+
 [[package]]
 name = "quote"
 version = "1.0.37"

crates/eww_shared_util/Cargo.toml

@@ -12,3 +12,4 @@ homepage = "https://github.com/elkowar/eww"
 serde.workspace = true
 derive_more.workspace = true
 ref-cast.workspace = true
+chrono = { workspace = true, features = ["unstable-locales"] }

crates/eww_shared_util/src/lib.rs

@@ -1,6 +1,8 @@
+pub mod locale;
 pub mod span;
 pub mod wrappers;
 
+pub use locale::*;
 pub use span::*;
 pub use wrappers::*;
 

crates/eww_shared_util/src/locale.rs

@@ -0,0 +1,14 @@
+use chrono::Locale;
+use std::env::var;
+
+/// Returns the `Locale` enum based on the `LC_TIME` environment variable.
+/// If the environment variable is not defined or is malformed use the POSIX locale.
+pub fn get_locale() -> Locale {
+    let locale_string: String =
+        var("LC_TIME").map_or_else(|_| "C".to_string(), |v| v.split(".").next().unwrap_or("C").to_string());
+
+    match (&*locale_string).try_into() {
+        Ok(x) => x,
+        Err(_) => Locale::POSIX,
+    }
+}

crates/simplexpr/Cargo.toml

@@ -16,7 +16,7 @@ eww_shared_util.workspace = true
 
 cached.workspace = true
 chrono-tz.workspace = true
-chrono.workspace = true
+chrono = { workspace = true, features = ["unstable-locales"] }
 itertools.workspace = true
 jaq-core.workspace = true
 jaq-parse.workspace = true

crates/simplexpr/src/eval.rs

@@ -7,7 +7,7 @@ use crate::{
     ast::{AccessType, BinOp, SimplExpr, UnaryOp},
     dynval::{ConversionError, DynVal},
 };
-use eww_shared_util::{Span, Spanned, VarName};
+use eww_shared_util::{get_locale, Span, Spanned, VarName};
 use std::{
     collections::HashMap,
     convert::{Infallible, TryFrom, TryInto},
@@ -467,12 +467,16 @@ fn call_expr_function(name: &str, args: Vec<DynVal>) -> Result<DynVal, EvalError
                 };
 
                 Ok(DynVal::from(match timezone.timestamp_opt(timestamp.as_i64()?, 0) {
-                    LocalResult::Single(t) | LocalResult::Ambiguous(t, _) => t.format(&format.as_string()?).to_string(),
+                    LocalResult::Single(t) | LocalResult::Ambiguous(t, _) => {
+                        t.format_localized(&format.as_string()?, get_locale()).to_string()
+                    }
                     LocalResult::None => return Err(EvalError::ChronoError("Invalid UNIX timestamp".to_string())),
                 }))
             }
             [timestamp, format] => Ok(DynVal::from(match Local.timestamp_opt(timestamp.as_i64()?, 0) {
-                LocalResult::Single(t) | LocalResult::Ambiguous(t, _) => t.format(&format.as_string()?).to_string(),
+                LocalResult::Single(t) | LocalResult::Ambiguous(t, _) => {
+                    t.format_localized(&format.as_string()?, get_locale()).to_string()
+                }
                 LocalResult::None => return Err(EvalError::ChronoError("Invalid UNIX timestamp".to_string())),
             })),
             _ => Err(EvalError::WrongArgCount(name.to_string())),