feat(cast): add flag equivalents of parseUnits, formatUnits

crates/cast/bin/args.rs

@@ -233,6 +233,38 @@ pub enum CastSubcommand {
         unit: String,
     },
 
+    /// Convert a number from decimal to smallest unit with arbitrary decimals.
+    ///
+    /// Examples:
+    /// - 1.0 6    (for USDC, result: 1000000)
+    /// - 2.5 12   (for 12 decimals token, result: 2500000000000)
+    /// - 1.23 3   (for 3 decimals token, result: 1230)
+    #[command(visible_aliases = &["--parse-units", "pun"])]
+    ParseUnits {
+        /// The value to convert.
+        value: Option<String>,
+
+        /// The unit to convert to.
+        #[arg(default_value = "18")]
+        unit: u8,
+    },
+
+    /// Format a number from smallest unit to decimal with arbitrary decimals.
+    ///
+    /// Examples:
+    /// - 1000000 6       (for USDC, result: 1.0)
+    /// - 2500000000000 12 (for 12 decimals, result: 2.5)
+    /// - 1230 3          (for 3 decimals, result: 1.23)
+    #[command(visible_aliases = &["--format-units", "fun"])]
+    FormatUnits {
+        /// The value to format.
+        value: Option<String>,
+
+        /// The unit to format to.
+        #[arg(default_value = "18")]
+        unit: u8,
+    },
+
     /// Convert an ETH amount to wei.
     ///
     /// Consider using --to-unit.

crates/cast/bin/main.rs

@@ -133,6 +133,14 @@ async fn main_args(args: CastArgs) -> Result<()> {
             let value = stdin::unwrap_line(value)?;
             println!("{}", SimpleCast::to_unit(&value, &unit)?);
         }
+        CastSubcommand::ParseUnits { value, unit } => {
+            let value = stdin::unwrap_line(value)?;
+            println!("{}", SimpleCast::parse_units(&value, unit)?);
+        }
+        CastSubcommand::FormatUnits { value, unit } => {
+            let value = stdin::unwrap_line(value)?;
+            println!("{}", SimpleCast::format_units(&value, unit)?);
+        }
         CastSubcommand::FromWei { value, unit } => {
             let value = stdin::unwrap_line(value)?;
             println!("{}", SimpleCast::from_wei(&value, &unit)?);

crates/cast/src/lib.rs

@@ -1351,17 +1351,62 @@ impl SimpleCast {
             .wrap_err("Could not convert to uint")?
             .0;
         let unit = unit.parse().wrap_err("could not parse units")?;
-        let mut formatted = ParseUnits::U256(value).format_units(unit);
+        Ok(Self::format_unit_as_string(value, unit))
+    }
+
+    /// Convert a number into a uint with arbitrary decimals.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// use cast::SimpleCast as Cast;
+    ///
+    /// # fn main() -> eyre::Result<()> {
+    /// assert_eq!(Cast::parse_units("1.0", 6)?, "1000000"); // USDC (6 decimals)
+    /// assert_eq!(Cast::parse_units("2.5", 6)?, "2500000");
+    /// assert_eq!(Cast::parse_units("1.0", 12)?, "1000000000000"); // 12 decimals
+    /// assert_eq!(Cast::parse_units("1.23", 3)?, "1230"); // 3 decimals
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub fn parse_units(value: &str, unit: u8) -> Result<String> {
+        let unit = Unit::new(unit).ok_or_else(|| eyre::eyre!("invalid unit"))?;
+
+        Ok(ParseUnits::parse_units(value, unit)?.to_string())
+    }
 
+    /// Format a number from smallest unit to decimal with arbitrary decimals.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// use cast::SimpleCast as Cast;
+    ///
+    /// # fn main() -> eyre::Result<()> {
+    /// assert_eq!(Cast::format_units("1000000", 6)?, "1"); // USDC (6 decimals)
+    /// assert_eq!(Cast::format_units("2500000", 6)?, "2.500000");
+    /// assert_eq!(Cast::format_units("1000000000000", 12)?, "1"); // 12 decimals
+    /// assert_eq!(Cast::format_units("1230", 3)?, "1.230"); // 3 decimals
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub fn format_units(value: &str, unit: u8) -> Result<String> {
+        let value = NumberWithBase::parse_int(value, None)?.number();
+        let unit = Unit::new(unit).ok_or_else(|| eyre::eyre!("invalid unit"))?;
+        Ok(Self::format_unit_as_string(value, unit))
+    }
+
+    // Helper function to format units as a string
+    fn format_unit_as_string(value: U256, unit: Unit) -> String {
+        let mut formatted = ParseUnits::U256(value).format_units(unit);
         // Trim empty fractional part.
         if let Some(dot) = formatted.find('.') {
             let fractional = &formatted[dot + 1..];
             if fractional.chars().all(|c: char| c == '0') {
                 formatted = formatted[..dot].to_string();
             }
         }
-
-        Ok(formatted)
+        formatted
     }
 
     /// Converts wei into an eth amount

crates/cast/tests/cli/main.rs

@@ -1387,3 +1387,39 @@ casttest!(hash_message, |_prj, cmd| {
 
 "#]]);
 });
+
+casttest!(parse_units, |_prj, cmd| {
+    cmd.args(["parse-units", "1.5", "6"]).assert_success().stdout_eq(str![[r#"
+1500000
+
+"#]]);
+
+    cmd.cast_fuse().args(["pun", "1.23", "18"]).assert_success().stdout_eq(str![[r#"
+1230000000000000000
+
+"#]]);
+
+    cmd.cast_fuse().args(["--parse-units", "1.23", "3"]).assert_success().stdout_eq(str![[r#"
+1230
+
+"#]]);
+});
+
+casttest!(format_units, |_prj, cmd| {
+    cmd.args(["format-units", "1000000", "6"]).assert_success().stdout_eq(str![[r#"
+1
+
+"#]]);
+
+    cmd.cast_fuse().args(["--format-units", "2500000", "6"]).assert_success().stdout_eq(str![[
+        r#"
+2.500000
+
+"#
+    ]]);
+
+    cmd.cast_fuse().args(["fun", "1230", "3"]).assert_success().stdout_eq(str![[r#"
+1.230
+
+"#]]);
+});