Order execution and using decimal

src/engine/fetch.rs

@@ -1,13 +1,14 @@
+use hypersdk::Decimal;
 use pulse_sdk::prelude::*;
 use serde_json::Value;
 use std::collections::HashMap;
 
-fn number(value: &Value, field: &str) -> Result<f64, String> {
+fn number(value: &Value, field: &str) -> Result<Decimal, String> {
     let raw = value[field]
         .as_str()
         .ok_or_else(|| format!("asset context field {field} must be a string"))?;
 
-    raw.parse::<f64>()
+    raw.parse::<Decimal>()
         .map_err(|error| format!("could not parse asset context field {field} ({raw}): {error}"))
 }
 
@@ -56,7 +57,7 @@ pub async fn fetch_watch_list(
         let previous_day_price = number(context, "prevDayPx")?;
         let volume_24h = number(context, "dayNtlVlm")?;
 
-        if previous_day_price <= 0.0 {
+        if previous_day_price.is_zero() || previous_day_price.is_sign_negative() {
             return Err(format!("{symbol} has an invalid previous-day price"));
         }
 
@@ -66,7 +67,8 @@ pub async fn fetch_watch_list(
                 symbol: Symbol(symbol.to_owned()),
                 price: USD(price),
                 volume_24h: USD(volume_24h),
-                trend: ((price / previous_day_price) - 1.0) * 100.0,
+                trend: ((price / previous_day_price) - <Decimal as From<i32>>::from(1))
+                    * <Decimal as From<i32>>::from(100),
             },
         );
     }