rename hat to cap

Clearer intent and avoids confusion with ds-chief `hat`. Another
candidate, `lid`, was considered but is being reserved for other
purposes.

DEVELOPING.md

@@ -44,7 +44,7 @@ Sai has the following core components:
 Sai is configured by the following 'risk parameters':
 
 - `way`: Sai reference price drift
-- `hat`: Debt ceiling
+- `cap`: Debt ceiling
 - `mat`: Liquidation ratio
 - `tax`: Stability fee
 - `axe`: Liquidation penalty
@@ -333,7 +333,7 @@ Script output gist
 - `top`: top-level system manager
 
 - `way`: which way the target price is heading
-- `hat`: upper limit of Sai issuance
+- `cap`: upper limit of Sai issuance
 - `mat`: lower limit of collateralisation
 - `tax`: continually paid by CDP holders
 - `axe`: penalty applied to bad CDP holders

README.md

@@ -92,7 +92,7 @@ Actions:
    safe            determine if a cup is safe
    setAxe          update the liquidation penalty
    setFee          update the governance fee
-   setHat          update the debt ceiling
+   setCap          update the debt ceiling
    setMat          update the liquidation ratio
    setTapGap       update the spread on `boom` and `bust`
    setTax          update the stability fee
@@ -115,7 +115,7 @@ Vars, Getters, Utils:
    fog             get the amount of skr pending liquidation
    gem             get the collateral token
    gov             get the governance token
-   hat             get the debt ceiling
+   cap             get the debt ceiling
    ice             get the good debt
    ink             get the amount of skr collateral locked in a cup
    joy             get the amount of surplus sai

bin/deploy-live-public

@@ -30,10 +30,10 @@ CHAIN=$(seth chain)
 . load-env-$CHAIN
 
 ##### configure risk params
-# mat = 1.5 axe = 1.2 hat = 100,000,000 gap = 1 [but configurable, +/- 5%] 
+# mat = 1.5 axe = 1.2 cap = 100,000,000 gap = 1 [but configurable, +/- 5%]
 # tax = way = 1 [default]
 
-seth send $SAI_MOM "setHat(uint256)" $(seth --to-uint256 $(seth --to-wei 100000000 ETH))
+seth send $SAI_MOM "setCap(uint256)" $(seth --to-uint256 $(seth --to-wei 100000000 ETH))
 seth send $SAI_MOM "setMat(uint256)" $(seth --to-uint256 $(seth --to-wei 1500000000 ETH))
 seth send $SAI_MOM "setAxe(uint256)" $(seth --to-uint256 $(seth --to-wei 1200000000 ETH))
 

bin/validate-deployment

@@ -9,7 +9,7 @@ test $(sai pip)     =
 test $(sai pep)     = 
 
 # risk parameters
-test $(sai hat)     = $(sai wad -h 100000000.0)
+test $(sai cap)     = $(sai wad -h 100000000.0)
 test $(sai mat)     = $(sai ray -h 1.50)
 test $(sai axe)     = $(sai ray -h 1.20)
 test $(sai tax)     = $(sai ray -h 1.0)

libexec/sai/sai-cap

@@ -0,0 +1,5 @@
+#!/usr/bin/env bash
+### sai-cap -- get the debt ceiling
+set -e
+wad=$(seth call "${SAI_TUB?}" "cap()")
+sai wad -h "$wad"

libexec/sai/sai-setCap

@@ -0,0 +1,9 @@
+#!/usr/bin/env bash
+### sai-setCap -- update the debt ceiling
+### Usage: sai setCap <new-cap>
+set -e
+[ $# = 1 ] || sai setCap --usage
+wad=$(sai wad -h "$1")
+echo >&2 "Setting cap to $wad..."
+wad=$(sai wad "$1")
+(set -x; seth send "${SAI_MOM?}" "setCap(uint256)" "$wad")

src/mom.sol

@@ -22,8 +22,8 @@ contract SaiMom is DSThing {
         vox = vox_;
     }
     // Debt ceiling
-    function setHat(uint wad) public note auth {
-        tub.mold("hat", wad);
+    function setCap(uint wad) public note auth {
+        tub.mold("cap", wad);
     }
     // Liquidation ratio
     function setMat(uint ray) public note auth {

src/sai.t.sol

@@ -205,7 +205,7 @@ contract SaiTestBase is DSTest, DSMath {
         mark(1 ether);
         mark(gov, 1 ether);
 
-        mom.setHat(20 ether);
+        mom.setCap(20 ether);
     }
 }
 
@@ -253,11 +253,11 @@ contract SaiTubTest is SaiTestBase {
     }
     function testMold() public {
         var setAxe = bytes4(keccak256('setAxe(uint256)'));
-        var setHat = bytes4(keccak256('setHat(uint256)'));
+        var setCap = bytes4(keccak256('setCap(uint256)'));
         var setMat = bytes4(keccak256('setMat(uint256)'));
 
-        assertTrue(mom.call(setHat, 0 ether));
-        assertTrue(mom.call(setHat, 5 ether));
+        assertTrue(mom.call(setCap, 0 ether));
+        assertTrue(mom.call(setCap, 5 ether));
 
         assertTrue(!mom.call(setAxe, ray(2 ether)));
         assertTrue( mom.call(setMat, ray(2 ether)));
@@ -410,15 +410,15 @@ contract SaiTubTest is SaiTestBase {
         tub.free(cup, 3 ether);  // 175% -- fails
     }
     function testFailDrawOverDebtCeiling() public {
-        mom.setHat(4 ether);
+        mom.setCap(4 ether);
         tub.join(10 ether);
         var cup = tub.open();
         tub.lock(cup, 10 ether);
 
         tub.draw(cup, 5 ether);
     }
     function testDebtCeiling() public {
-        mom.setHat(5 ether);
+        mom.setCap(5 ether);
         mom.setMat(ray(2 ether));  // require 200% collat
         tub.join(10 ether);
         var cup = tub.open();
@@ -442,7 +442,7 @@ contract SaiTubTest is SaiTestBase {
 contract CageTest is SaiTestBase {
     // ensure cage sets the settle prices right
     function cageSetup() public returns (bytes32) {
-        mom.setHat(5 ether);            // 5 sai debt ceiling
+        mom.setCap(5 ether);            // 5 sai debt ceiling
         mark(1 ether);   // price 1:1 gem:ref
         mom.setMat(ray(2 ether));       // require 200% collat
         tub.join(10 ether);
@@ -1179,7 +1179,7 @@ contract LiquidationTest is SaiTestBase {
         return wdiv(min, jam);
     }
     function testLiq() public {
-        mom.setHat(100 ether);
+        mom.setCap(100 ether);
         mark(2 ether);
 
         tub.join(10 ether);
@@ -1212,7 +1212,7 @@ contract LiquidationTest is SaiTestBase {
         return wdiv(pro, con);
     }
     function testCollat() public {
-        mom.setHat(100 ether);
+        mom.setCap(100 ether);
         mark(2 ether);
 
         tub.join(10 ether);
@@ -1240,7 +1240,7 @@ contract LiquidationTest is SaiTestBase {
     }
 
     function testBustMint() public {
-        mom.setHat(100 ether);
+        mom.setCap(100 ether);
         mom.setMat(ray(wdiv(3 ether, 2 ether)));  // 150% liq limit
         mark(2 ether);
 
@@ -1287,7 +1287,7 @@ contract LiquidationTest is SaiTestBase {
         assertEq(skr.totalSupply(), 12 ether);
     }
     function testBustNoMint() public {
-        mom.setHat(1000 ether);
+        mom.setCap(1000 ether);
         mom.setMat(ray(2 ether));    // 200% liq limit
         mom.setAxe(ray(1.5 ether));  // 150% liq penalty
         mark(20 ether);
@@ -1612,7 +1612,7 @@ contract TaxTest is SaiTestBase {
         mark(10 ether);
         gem.mint(1000 ether);
 
-        mom.setHat(1000 ether);
+        mom.setCap(1000 ether);
         mom.setTax(1000000564701133626865910626);  // 5% / day
         cup = tub.open();
         tub.join(100 ether);
@@ -1768,7 +1768,7 @@ contract WayTest is SaiTestBase {
         mark(10 ether);
         gem.mint(1000 ether);
 
-        mom.setHat(1000 ether);
+        mom.setCap(1000 ether);
 
         cup = tub.open();
         tub.join(100 ether);
@@ -2020,7 +2020,7 @@ contract GasTest is SaiTestBase {
         mark(1 ether);
         gem.mint(1000 ether);
 
-        mom.setHat(1000 ether);
+        mom.setCap(1000 ether);
 
         cup = tub.open();
         tub.join(1000 ether);
@@ -2117,7 +2117,7 @@ contract FeeTest is SaiTestBase {
         gem.mint(1000 ether);
         gov.mint(100 ether);
 
-        mom.setHat(1000 ether);
+        mom.setCap(1000 ether);
         mom.setFee(1000000564701133626865910626);  // 5% / day
 
         // warp(1 days);  // make chi,rhi != 1
@@ -2264,7 +2264,7 @@ contract FeeTaxTest is SaiTestBase {
         gem.mint(1000 ether);
         gov.mint(100 ether);
 
-        mom.setHat(1000 ether);
+        mom.setCap(1000 ether);
         mom.setFee(1000000564701133626865910626);  // 5% / day
         mom.setTax(1000000564701133626865910626);  // 5% / day
 
@@ -2342,7 +2342,7 @@ contract FeeTaxTest is SaiTestBase {
 
 contract AxeTest is SaiTestBase {
     function axeSetup() public returns (bytes32) {
-        mom.setHat(1000 ether);
+        mom.setCap(1000 ether);
         mark(1 ether);
         mom.setMat(ray(2 ether));       // require 200% collat
         tub.join(20 ether);

src/tub.sol

@@ -33,7 +33,7 @@ contract SaiTub is DSThing, SaiTubEvents {
     address  public  pit;  // Governance Vault
 
     uint256  public  axe;  // Liquidation penalty
-    uint256  public  hat;  // Debt ceiling
+    uint256  public  cap;  // Debt ceiling
     uint256  public  mat;  // Liquidation ratio
     uint256  public  tax;  // Stability fee
     uint256  public  fee;  // Governance fee
@@ -130,7 +130,7 @@ contract SaiTub is DSThing, SaiTubEvents {
     //--Risk-parameter-config-------------------------------------------
 
     function mold(bytes32 param, uint val) public note auth {
-        if      (param == 'hat') hat = val;
+        if      (param == 'cap') cap = val;
         else if (param == 'mat') { require(val >= RAY); mat = val; }
         else if (param == 'tax') { require(val >= RAY); drip(); tax = val; }
         else if (param == 'fee') { require(val >= RAY); drip(); fee = val; }
@@ -269,7 +269,7 @@ contract SaiTub is DSThing, SaiTubEvents {
         sai.mint(cups[cup].lad, wad);
 
         require(safe(cup));
-        require(sai.totalSupply() <= hat);
+        require(sai.totalSupply() <= cap);
     }
     function wipe(bytes32 cup, uint wad) public note {
         require(!off);