V5 Decimal numeric type in Move Vm (#654)

* add decimal native

* ol_decimal.rs tests

* decimal irrational number test

* change move decimal type to u128 to use throughout.

* patch negative number casting

language/diem-framework/modules/0L/Decimal.move

@@ -0,0 +1,169 @@
+address 0x1 {
+module Decimal {
+    // The Move Decimal data structure is optimized for readability and compatibility.
+    // In particular it is indended for compatibility with the underlying rust_decimal crate https://github.com/paupino/rust-decimal. In that library a new decimal type is initialized with Decimal::from_i128_with_scale(mantissa: i128, scale: u32)
+    // Note: While the underlying Rust crate type has optimal storage characteristics, this Move decimal representation is NOT optimized for storage.
+
+    struct Decimal has key, store, drop {
+        sign: bool,
+        int: u128,
+        scale: u8, // max intger is number 28
+    }
+
+    // while stored in u128, the largest integer possible in the rust_decimal vm dependency is 2^96
+    const MAX_RUST_DECIMAL_U128: u128 = 79228162514264337593543950335;
+
+    // pair decimal ops
+    const ADD: u8 = 1;
+    const SUB: u8 = 2;
+    const MUL: u8 = 3;
+    const DIV: u8 = 4;
+    const POW: u8 = 5;
+    const ROUND: u8 = 6;
+
+    // single ops
+    const SQRT: u8 = 100;
+    const TRUNC: u8 = 101;
+
+    const ROUND_MID_TO_EVEN: u8 = 0; // This is the default in the rust_decimal lib.
+    const ROUND_MID_FROM_ZERO: u8 = 1;
+
+
+
+    native public fun decimal_demo(sign: bool, int: u128, scale: u8): (bool, u128, u8);
+
+    native public fun single_op(op_id: u8, sign: bool, int: u128, scale: u8): (bool, u128, u8);
+
+    native public fun pair_op(
+      op_id: u8,
+      rounding_strategy_id: u8,
+      // left number
+      sign_1: bool,
+      int_1: u128,
+      scale_1: u8,
+      // right number
+      sign_2: bool,
+      int_2: u128,
+      scale_3: u8
+    ): (bool, u128, u8);
+
+    public fun new(sign: bool, int: u128, scale: u8): Decimal {
+
+      assert(int < MAX_RUST_DECIMAL_U128, 01);
+
+      // check scale < 28
+      assert(scale < 28, 02);
+
+      return Decimal {
+        sign: sign,
+        int: int,
+        scale: scale
+      }
+    }
+
+    /////// SUGAR /////////
+    public fun trunc(d: &Decimal): Decimal {
+      let (sign, int, scale) = single_op(TRUNC, *&d.sign, *&d.int, *&d.scale);
+      return Decimal {
+        sign: sign,
+        int: int,
+        scale: scale,
+      }
+    }
+
+    public fun sqrt(d: &Decimal): Decimal {
+      let (sign, int, scale) = single_op(SQRT, *&d.sign, *&d.int, *&d.scale);
+      return Decimal {
+        sign: sign,
+        int: int,
+        scale: scale,
+      }
+    }
+
+    public fun add(l: &Decimal, r: &Decimal): Decimal {
+      let (sign, int, scale) = pair_op(ADD, ROUND_MID_TO_EVEN, *&l.sign, *&l.int, *&l.scale,  *&r.sign, *&r.int, *&r.scale);
+      return Decimal {
+        sign: sign,
+        int: int,
+        scale: scale,
+      }
+    }
+
+    public fun sub(l: &Decimal, r: &Decimal): Decimal {
+      let (sign, int, scale) = pair_op(SUB, ROUND_MID_TO_EVEN, *&l.sign, *&l.int, *&l.scale,  *&r.sign, *&r.int, *&r.scale);
+      return Decimal {
+        sign: sign,
+        int: int,
+        scale: scale,
+      }
+    }
+    public fun mul(l: &Decimal, r: &Decimal): Decimal {
+      let (sign, int, scale) = pair_op(MUL, ROUND_MID_TO_EVEN, *&l.sign, *&l.int, *&l.scale,  *&r.sign, *&r.int, *&r.scale);
+      return Decimal {
+        sign: sign,
+        int: int,
+        scale: scale,
+      }
+    }
+
+     public fun div(l: &Decimal, r: &Decimal): Decimal {
+      let (sign, int, scale) = pair_op(DIV, ROUND_MID_TO_EVEN, *&l.sign, *&l.int, *&l.scale,  *&r.sign, *&r.int, *&r.scale);
+      return Decimal {
+        sign: sign,
+        int: int,
+        scale: scale,
+      }
+    }
+
+
+    public fun rescale(l: &Decimal, r: &Decimal): Decimal {
+      let (sign, int, scale) = pair_op(0, ROUND_MID_TO_EVEN, *&l.sign, *&l.int, *&l.scale,  *&r.sign, *&r.int, *&r.scale);
+      return Decimal {
+        sign: sign,
+        int: int,
+        scale: scale,
+      }
+    }
+
+    public fun round(l: &Decimal, r: &Decimal, strategy: u8): Decimal {
+      let (sign, int, scale) = pair_op(ROUND, strategy, *&l.sign, *&l.int, *&l.scale,  *&r.sign, *&r.int, *&r.scale);
+      return Decimal {
+        sign: sign,
+        int: int,
+        scale: scale,
+      }
+    }
+
+
+    public fun power(l: &Decimal, r: &Decimal): Decimal {
+      let (sign, int, scale) = pair_op(POW, ROUND_MID_TO_EVEN, *&l.sign, *&l.int, *&l.scale,  *&r.sign, *&r.int, *&r.scale);
+      return Decimal {
+        sign: sign,
+        int: int,
+        scale: scale,
+      }
+    }
+
+    ///// GETTERS /////
+
+    // unwrap creates a new decimal instance
+    public fun unwrap(d: &Decimal): (bool, u128, u8) {
+      return (*&d.sign, *&d.int, *&d.scale)
+    }
+
+    // borrow sign
+    public fun borrow_sign(d: &Decimal): &bool {
+      return &d.sign
+    }
+
+    // borrows the value of the integer
+    public fun borrow_int(d: &Decimal): &u128 {
+      return &d.int
+    }
+
+    // borrow sign
+    public fun borrow_scale(d: &Decimal): &u8 {
+      return &d.scale
+    }
+}
+}

language/diem-framework/modules/0L/Demo_Bonding.move

@@ -0,0 +1,179 @@
+address 0x1 {
+module Bonding {
+  // use 0x1::Signer;
+  use 0x1::Decimal;
+  use 0x1::Debug::print;
+
+  struct CurveState has key {
+    is_deprecated: bool,
+    reserve: u128, //todo: change to Diem<XUS>,
+    supply_issued: u128,
+  }
+
+  struct Token has key, store { 
+    value: u128
+  }
+
+  // fun sunset() {
+  //   // if true state.is_deprecated == true
+  //   // allow holders to redeem at the spot price at sunset.
+  //   // cannot receive new deposits
+  //   //TBD
+  // }
+
+  ///////// Initialization /////////
+  public fun initialize_curve(
+    service: &signer,
+    deposit: u128, // Diem<XUS>,
+    supply_init: u128,
+  ) {
+    // let deposit_value = Diem::value<XUS>(&deposit);
+    assert(deposit > 0, 7357001);
+
+    let init_state = CurveState {
+      is_deprecated: false, // deprecate mode
+      reserve: deposit,
+      supply_issued: supply_init,
+    };
+
+    // This initializes the contract, and stores the contract state at the address of sender. TDB where the state gets stored.
+    move_to<CurveState>(service, init_state);
+
+    let first_token = Token { 
+      value: supply_init
+    };
+
+    // minting the first coin, sponsor is recipent of initial coin.
+    move_to<Token>(service, first_token);
+  }
+
+  /////////// Calculations /////////
+  public fun deposit_calc(add_to_reserve: u128, reserve: u128, supply: u128): u128 {
+
+    let one = Decimal::new(true, 1, 0);
+    print(&one);
+
+    let add_dec = Decimal::new(true, add_to_reserve, 0);
+    print(&add_dec);
+
+    let reserve_dec = Decimal::new(true, reserve, 0);
+    print(&reserve_dec);
+
+    let supply_dec = Decimal::new(true, supply, 0);
+    print(&supply_dec);
+
+    // formula: 
+    // supply * sqrt(one+(add_to_reserve/reserve))
+
+    let a = Decimal::div(&add_dec, &reserve_dec);
+    print(&a);
+    let b = Decimal::add(&one, &a);
+    print(&b);
+    let c = Decimal::sqrt(&b);
+    print(&c);
+    let d = Decimal::mul(&supply_dec, &c);
+    print(&d);
+    let int = Decimal::borrow_int(&Decimal::trunc(&d));
+    print(int);
+
+    return *int
+  }
+
+//   fun withdraw_curve(remove_from_supply: u128, supply: u128, reserve: u128):u128 {
+//     // TODO: 
+//     // formula: reserve * (one - remove_from_supply/supply )^2
+//     // let one = Decimal::new(true, 1, 0);
+//     
+//     
+//   }
+
+
+  ///////// API /////////
+  // this simulates the depositing and getting a minted token out, but just using integers, not coin types for now.
+  public fun test_bond_to_mint(_sender: &signer, service_addr: address, deposit: u128): u128 acquires CurveState {
+    assert(exists<CurveState>(service_addr), 73570002);
+    let state = borrow_global_mut<CurveState>(service_addr);
+
+    let post_supply = deposit_calc(deposit, state.reserve, state.supply_issued);
+    print(&post_supply);
+    assert(post_supply > state.supply_issued, 73570003);
+    let mint = post_supply - state.supply_issued;
+    print(&mint);
+    // update the new curve state
+    state.reserve = state.reserve + deposit;
+    state.supply_issued = state.supply_issued + mint;
+    // print(&state);
+    mint
+  }
+
+//   public fun burn_to_withdraw(sender: &signer, service_addr: address, burn_value: u128):Decimal acquires CurveState, Token {
+
+//     assert(exists<CurveState>(service_addr), 73570002);
+//     let sender_addr = Signer::address_of(sender);
+//     assert(exists<Token>(sender_addr), 73570003);
+//     assert(Coin::balance(sender_addr) >= burn_value, 73570004);
+
+//     let state = borrow_global_mut<CurveState>(service_addr);
+
+//     // Calculate the reserve change.
+//     let remove_from_supply = Decimal::new(burn_value);
+//     let withdraw_value = withdraw_curve(remove_from_supply, service_addr, state.reserve);
+
+//     withdraw_token_from(sender, burn_value);
+//     // new curve state
+//     state.reserve = state.reserve - withdraw_value;
+//     state.supply = state.supply - burn_value;
+//     withdraw_value
+//   }
+
+
+//   // Merges a GAS coin.
+//   fun deposit_gas_and_merge(sender: &signer, coin: GAS) acquires Token {
+//     //TODO: merges gas coin to bonding curve reserve
+//   }
+
+//   // Splits a coin to be used.
+//   fun withdraw_token_and_split_gas(sender: &signer, sub_value: Decimal) acquires Token {
+//    //TODO:
+//   }
+
+
+//   ///////// GETTERS /////////
+
+  public fun get_curve_state(sponsor_address: address): (u128, u128) acquires CurveState {
+    let state = borrow_global<CurveState>(sponsor_address); 
+    (state.reserve, state.supply_issued)
+  }
+
+//   public fun get_user_balance(addr: address): Decimal acquires Token {
+//     let state = borrow_global<Token>(addr);
+//     state.value
+//   }
+
+//   // This is a steady state getter
+//   public fun calc_spot_price_from_state(sponsor_addr: address): Decimal acquires CurveState {
+//     let state = borrow_global_mut<CurveState>(sponsor_addr);
+//     state.kappa * (state.reserve/state.supply)
+//   }
+
+
+//   ///////// TEST /////////
+
+//   // // NOTE:  This "invariant" may not be invariant with rounding issues.
+//   // public fun test_get_curve_invariant(sponsor_addr: address):Decimal acquires CurveState {
+//   //   let state = borrow_global_mut<CurveState>(sponsor_addr);
+//   //   let two = FixedPoint32::create_from_raw_value(2);
+//   //   let zero = FixedPoint32::create_from_raw_value(0);
+
+//   //   // TOOD: when we have native math lib the formula will be:
+//   //   // (state.supply, to power of state.kappa) / state.reserve
+//   //   if (state.kappa == two ) {
+//   //     return (state.supply * state.supply) / state.reserve
+//   //   };
+//   //   zero
+//   // }
+
+
+
+}
+}

language/diem-framework/modules/doc/Cases.md

@@ -85,7 +85,7 @@ set and/or jailed. To be compliant, validators must be BOTH validating and minin
     <a href="Roles.md#0x1_Roles_assert_diem_root">Roles::assert_diem_root</a>(vm);
     // did the validator sign blocks above threshold?
     <b>let</b> signs = <a href="Stats.md#0x1_Stats_node_above_thresh">Stats::node_above_thresh</a>(vm, node_addr, height_start, height_end);
-    <b>let</b> mines = <a href="MinerState.md#0x1_MinerState_node_above_thresh">MinerState::node_above_thresh</a>(vm, node_addr);
+    <b>let</b> mines = <a href="MinerState.md#0x1_MinerState_node_above_thresh">MinerState::node_above_thresh</a>(node_addr);
 
     <b>if</b> (signs && mines) {
         <a href="Cases.md#0x1_Cases_VALIDATOR_COMPLIANT">VALIDATOR_COMPLIANT</a> // compliant: in next set, gets paid, weight increments