Refactor similar die functions

3 files changed, 46 insertions, 95 deletions

diff --git a/__tests__/dice.test.js b/__tests__/dice.test.js
index fb8a155..caba0a9 100644
--- a/__tests__/dice.test.js
+++ b/__tests__/dice.test.js
@@ -7,13 +7,13 @@ const {
   bonusAdd,
   bonusSubtract,
   negative,
-  explode,
+  explodeAbove,
   explodeUnder,
   keepHigh,
   keepLow,
-  again,
+  againAbove,
   againUnder,
-  threshold,
+  thresholdHigh,
   thresholdLow
 } = require('../src/dice.js')
 
@@ -452,7 +452,7 @@ describe('compound dice', () => {
 
 describe('exploding dice', () => {
   describe('6E1d6', () => {
-    const die = explode(constant(6), d(constant(1), constant(6)))
+    const die = explodeAbove(constant(6), d(constant(1), constant(6)))
     testDie(die, {
       diceCount: 1,
       average: {
@@ -470,7 +470,7 @@ describe('exploding dice', () => {
   })
 
   describe('6E2d6', () => {
-    const die = explode(constant(6), d(constant(2), constant(6)))
+    const die = explodeAbove(constant(6), d(constant(2), constant(6)))
     testDie(die, {
       diceCount: 2,
       average: {
@@ -560,7 +560,7 @@ describe('keep', () => {
 
 describe('again', () => {
   describe('10A1d10', () => {
-    const die = again(constant(10), d(constant(1), constant(10)))
+    const die = againAbove(constant(10), d(constant(1), constant(10)))
 
     testDie(die, {
       variableDiceCount: {
@@ -608,7 +608,7 @@ describe('again', () => {
 
 describe('threshold', () => {
   describe('8T3d10', () => {
-    const die = threshold(constant(8), d(constant(3), constant(10)))
+    const die = thresholdHigh(constant(8), d(constant(3), constant(10)))
 
     testDie(die, {
       diceCount: 3,
diff --git a/index.js b/index.js
index 6dd9a5f..1851a77 100644
--- a/index.js
+++ b/index.js
@@ -8,7 +8,7 @@ const interpret = tree => {
   case 'd':
     return D.d(interpret(tree.left), interpret(tree.right))
   case 'E':
-    return D.explode(interpret(tree.left), interpret(tree.right))
+    return D.explodeAbove(interpret(tree.left), interpret(tree.right))
   case 'e':
     return D.explodeUnder(interpret(tree.left), interpret(tree.right))
   case 'K':
@@ -16,11 +16,11 @@ const interpret = tree => {
   case 'k':
     return D.keepLow(interpret(tree.left), interpret(tree.right))
   case 'A':
-    return D.again(interpret(tree.left), interpret(tree.right))
+    return D.againAbove(interpret(tree.left), interpret(tree.right))
   case 'a':
     return D.againUnder(interpret(tree.left), interpret(tree.right))
   case 'T':
-    return D.threshold(interpret(tree.left), interpret(tree.right))
+    return D.thresholdHigh(interpret(tree.left), interpret(tree.right))
   case 't':
     return D.thresholdLow(interpret(tree.left), interpret(tree.right))
   case 'add':
diff --git a/src/dice.js b/src/dice.js
index 53d337d..828a772 100644
--- a/src/dice.js
+++ b/src/dice.js
@@ -1,3 +1,6 @@
+const greaterThanOrEqual = (a, b) => a >= b
+const lessThanOrEqual = (a, b) => a <= b
+
 const constant = n => () => [() => n]
 
 const pool = (die) => {
@@ -58,13 +61,13 @@ const bonusSubtract = (die1, die2) => {
   }
 }
 
-const explode = (die1, die2) => {
+const explode = (comparison, die1, die2) => {
   return () => {
     const explodeOn = roll(die1)
     return die2().map(die => () => {
       let lastRoll = die()
       let total = lastRoll
-      while (lastRoll >= explodeOn) {
+      while (comparison(lastRoll, explodeOn)) {
         lastRoll = die()
         total += lastRoll
       }
@@ -73,26 +76,21 @@ const explode = (die1, die2) => {
   }
 }
 
+const explodeAbove = (die1, die2) => {
+  return explode(greaterThanOrEqual, die1, die2)
+}
+
 const explodeUnder = (die1, die2) => {
-  return () => {
-    const explodeOn = roll(die1)
-    return die2().map(die => () => {
-      let lastRoll = die()
-      let total = lastRoll
-      while (lastRoll <= explodeOn) {
-        lastRoll = die()
-        total += lastRoll
-      }
-      return total
-    })
-  }
+  return explode(lessThanOrEqual, die1, die2)
 }
 
-const keepHigh = (die1, die2) => {
+
+
+const keep = (order, die1, die2) => {
   return () => {
     const numberToKeep = roll(die1)
     let rolls = die2().map(die => [die, die()])
-    rolls.sort((a, b) => (a[1] - b[1])).reverse()
+    rolls.sort(order)
     return rolls.slice(0, numberToKeep).map(pair => {
       let returnedOriginal = false
       return () => {
@@ -107,26 +105,15 @@ const keepHigh = (die1, die2) => {
   }
 }
 
+const keepHigh = (die1, die2) => {
+  return keep((a, b) => (b[1] - a[1]), die1, die2)
+}
+
 const keepLow = (die1, die2) => {
-  return () => {
-    const numberToKeep = roll(die1)
-    let rolls = die2().map(die => [die, die()])
-    rolls.sort((a, b) => (a[1] - b[1]))
-    return rolls.slice(0, numberToKeep).map(pair => {
-      let returnedOriginal = false
-      return () => {
-        if (!returnedOriginal) {
-          returnedOriginal = true
-          return pair[1]
-        } else {
-          return pair[0]()
-        }
-      }
-    })
-  }
+  return keep((a, b) => (a[1] - b[1]), die1, die2)
 }
 
-const again = (die1, die2) => {
+const again = (comparison, die1, die2) => {
   return () => {
     const againOn = roll(die1)
     let rolls = []
@@ -135,7 +122,7 @@ const again = (die1, die2) => {
     const rollDie = (die) => {
       const roll = die()
 
-      if (roll >= againOn) {
+      if (comparison(roll, againOn)) {
         rollAgain.push(die)
       }
 
@@ -162,49 +149,21 @@ const again = (die1, die2) => {
   }
 }
 
-const againUnder = (die1, die2) => {
-  return () => {
-    const againOn = roll(die1)
-    let rolls = []
-    let rollAgain = []
-
-    const rollDie = (die) => {
-      const roll = die()
-
-      if (roll <= againOn) {
-        rollAgain.push(die)
-      }
-
-      let returnedOriginal = false
-      rolls.push(() => {
-        if (!returnedOriginal) {
-          returnedOriginal = true
-          return roll
-        } else {
-          return die()
-        }
-      })
-    }
-
-    die2().forEach(rollDie)
-
-    while (rollAgain.length > 0) {
-      const oldRollAgain = rollAgain
-      rollAgain = []
-      oldRollAgain.forEach(rollDie)
-    }
+const againAbove = (die1, die2) => {
+  return again(greaterThanOrEqual, die1, die2)
+}
 
-    return rolls
-  }
+const againUnder = (die1, die2) => {
+  return again(lessThanOrEqual, die1, die2)
 }
 
-const threshold = (die1, die2) => {
+const threshold = (comparison, die1, die2) => {
   return () => {
     const cutoff = roll(die1)
 
     return die2().map(die => {
       return () => {
-        if (die() >= cutoff) {
+        if (comparison(die(), cutoff)) {
           return 1
         } else {
           return 0
@@ -214,20 +173,12 @@ const threshold = (die1, die2) => {
   }
 }
 
-const thresholdLow = (die1, die2) => {
-  return () => {
-    const cutoff = roll(die1)
+const thresholdHigh = (die1, die2) => {
+  return threshold(greaterThanOrEqual, die1, die2)
+}
 
-    return die2().map(die => {
-      return () => {
-        if (die() <= cutoff) {
-          return 1
-        } else {
-          return 0
-        }
-      }
-    })
-  }
+const thresholdLow = (die1, die2) => {
+  return threshold(lessThanOrEqual, die1, die2)
 }
 
 exports.pool = pool
@@ -239,11 +190,11 @@ exports.subtract = subtract
 exports.bonusAdd = bonusAdd
 exports.bonusSubtract = bonusSubtract
 exports.negative = negative
-exports.explode = explode
+exports.explodeAbove = explodeAbove
 exports.explodeUnder = explodeUnder
 exports.keepHigh = keepHigh
 exports.keepLow = keepLow
-exports.again = again
+exports.againAbove = againAbove
 exports.againUnder = againUnder
-exports.threshold = threshold
+exports.thresholdHigh = thresholdHigh
 exports.thresholdLow = thresholdLow