Seth: --to-fix

dapptools/src/seth.rs

@@ -28,6 +28,9 @@ async fn main() -> eyre::Result<()> {
         Subcommands::ToBytes32 { bytes } => {
             println!("{}", SimpleSeth::to_bytes32(&bytes)?);
         }
+        Subcommands::ToFix { decimals, value } => {
+            println!("{}", SimpleSeth::to_fix(unwrap_or_stdin(decimals)?, unwrap_or_stdin(value)?));
+        }
         Subcommands::Block {
             rpc_url,
             block,

dapptools/src/seth_opts.rs

@@ -23,6 +23,9 @@ pub enum Subcommands {
     #[structopt(name = "--to-bytes32")]
     #[structopt(about = "left-pads a hex bytes string to 32 bytes)")]
     ToBytes32 { bytes: String },
+    #[structopt(name = "--to-fix")]
+    #[structopt(about = "convert integers into fixed point with specified decimals")]
+    ToFix { decimals: Option<u128>, value: Option<u128> },
     #[structopt(name = "block")]
     #[structopt(
         about = "Prints information about <block>. If <field> is given, print only the value of that field"

seth/src/lib.rs

@@ -211,6 +211,31 @@ impl SimpleSeth {
         let s: String = s.as_bytes().to_hex();
         format!("0x{}", s)
     }
+
+    /// Converts integers with specified decimals into fixed point numbers
+    ///
+    /// ```
+    /// use seth::SimpleSeth as Seth;
+    ///
+    /// assert_eq!(Seth::to_fix(0, 10), "10.");
+    /// assert_eq!(Seth::to_fix(1, 10), "1.0");
+    /// assert_eq!(Seth::to_fix(2, 10), "0.10");
+    /// assert_eq!(Seth::to_fix(3, 10), "0.010");
+    /// ```
+    pub fn to_fix(decimals: u128, value: u128) -> String {
+        let mut value: String = value.to_string();
+        let decimals = decimals as usize;
+
+        if decimals >= value.len() {
+            // {0}.{0 * (number_of_decimals - value.len())}{value}
+            format!("0.{:0>1$}", value, decimals)
+        } else {
+            // Insert decimal at -idx (i.e 1 => decimal idx = -1)
+            value.insert(value.len() - decimals, '.');
+            value
+        }
+    }
+
     /// Converts decimal input to hex
     ///
     /// ```