Feature: implemented string.format

COMPATIBILITY.md

@@ -93,7 +93,7 @@ likely not be implemented due to differences between piccolo and PUC-Lua.
 | 🔵   | `char(args...)`                   |             |       |
 | ⚫️️   | `dump(function[, strip])`         |             |       |
 | ⚫️️   | `find(s, pattern[, init, plain])` |             |       |
-| ⚫️️   | `format(formatstring, args...)`   |             |       |
+| 🔵   | `format(formatstring, args...)`   |             |       |
 | ⚫️️   | `gmatch(s, pattern[, init])`      |             |       |
 | ⚫️️   | `gsub(s, pattern, repl[, n])`     |             |       |
 | 🔵     | `len(s)`                          |             |       |

Cargo.toml

@@ -41,6 +41,7 @@ repository.workspace = true
 ahash.workspace = true
 allocator-api2.workspace = true
 anyhow.workspace = true
+fhex = "1.0.0"
 gc-arena.workspace = true
 hashbrown.workspace = true
 rand.workspace = true

src/stdlib/string.rs

@@ -1,4 +1,6 @@
-use crate::{Callback, CallbackReturn, Context, FromValue, String, Table, Value};
+use crate::{Callback, CallbackReturn, Context, FromValue, IntoValue, String, Table, Value};
+
+mod format;
 
 pub fn load_string<'gc>(ctx: Context<'gc>) {
     let string = Table::new(&ctx);
@@ -97,6 +99,25 @@ pub fn load_string<'gc>(ctx: Context<'gc>) {
         }),
     );
 
+    string.set_field(
+        ctx,
+        "format",
+        Callback::from_fn(&ctx, |ctx, _, mut stack| {
+            let formatstring = stack.consume::<String>(ctx)?;
+            let formatstring = formatstring.to_str()?;
+
+            let args: Vec<Value> = stack.into_iter().collect();
+
+            let formatted = format::format(&ctx, formatstring, &args).map_err(|err| {
+                let err = err.to_string();
+                err.into_value(ctx)
+            })?;
+
+            stack.replace(ctx, formatted);
+            Ok(CallbackReturn::Return)
+        }),
+    );
+
     ctx.set_global("string", string);
 }