Add HALF keyword support to exchange deposit

src/amount.rs

@@ -0,0 +1,26 @@
+pub enum Amount {
+    Half,
+    All,
+    Exact(u64),
+}
+
+impl Amount {
+    pub fn unwrap_or(self, all_amount: u64) -> u64 {
+        match self {
+            Self::All => all_amount,
+            Self::Half => all_amount / 2,
+            Self::Exact(exact) => exact,
+        }
+    }
+
+    pub fn unwrap_or_else<F>(self, f: F) -> u64
+    where
+        F: std::ops::FnOnce() -> u64,
+    {
+        if let Self::Exact(exact) = self {
+            exact
+        } else {
+            f()
+        }
+    }
+}

src/main.rs

@@ -1,3 +1,4 @@
+mod amount;
 mod db;
 mod field_as_string;
 mod get_transaction_balance_change;
@@ -6,7 +7,7 @@ mod rpc_client_utils;
 mod stake_spreader;
 
 use {
-    crate::get_transaction_balance_change::*,
+    crate::{amount::Amount, get_transaction_balance_change::*},
     chrono::prelude::*,
     chrono_humanize::HumanTime,
     clap::{
@@ -390,7 +391,7 @@ async fn process_exchange_deposit<T: Signers>(
     exchange_client: &dyn ExchangeClient,
     token: MaybeToken,
     deposit_address: Pubkey,
-    amount: Option<u64>,
+    amount: Amount,
     from_address: Pubkey,
     if_source_balance_exceeds: Option<u64>,
     if_exchange_balance_less_than: Option<u64>,
@@ -4968,7 +4969,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
                                 .takes_value(true)
                                 .validator(is_amount_or_all)
                                 .required(true)
-                                .help("Amount of liquidity tokens to deposit; accepts keyword ALL"),
+                                .help("Amount of liquidity tokens to deposit; accepts keywords ALL and HALF"),
                         )
                         .arg(
                             Arg::with_name("liquidity_token")
@@ -6345,8 +6346,9 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
                 ("deposit", Some(arg_matches)) => {
                     let token = MaybeToken::from(value_t!(arg_matches, "token", Token).ok());
                     let amount = match arg_matches.value_of("amount").unwrap() {
-                        "ALL" => None,
-                        amount => Some(token.amount(amount.parse().unwrap())),
+                        "ALL" => Amount::All,
+                        "HALF" => Amount::Half,
+                        amount => Amount::Exact(token.amount(amount.parse().unwrap())),
                     };
                     let if_source_balance_exceeds =
                         value_t!(arg_matches, "if_source_balance_exceeds", f64)