improve die parser: allow chained expressions

src/bot/config/configurator.py

@@ -18,7 +18,7 @@ class YamlConfigSettingsSource(PydanticBaseSettingsSource):
     at the project's root.
 
     Here we happen to choose to use the `env_file_encoding` from Config
-    when reading `config.json`
+    when reading `config.yaml`
     """
 
     @functools.lru_cache
@@ -59,11 +59,19 @@ class YamlConfigSettingsSource(PydanticBaseSettingsSource):
 
 
 class DiscordSettings(BaseModel):
+    """
+    Holds all the settings needed to configure the bot for Discord usage.
+    """
+
     token: str = Field()
     command_prefix: str = Field(default=".")
 
 
 class Settings(BaseSettings):
+    """
+    Settings class for the bot
+    """
+
     discord: DiscordSettings
 
     @classmethod

src/bot/discord/commands/dice.py

@@ -16,11 +16,13 @@ class DiceCog(commands.Cog):
         - 2d20 will roll a two d20 dies and multiply the result by two.
         - 2d20+5 will roll a two d20 dies and multiply the result by two and ads 5.
         """
+        if dice_expression == "":
+            return
         if dice_expression == "0/0":  # easter eggs
             return await ctx.send("What do you expect me to do, destroy the universe?")
 
         try:
-            roll_result = DiceRoller.roll(dice_expression)
+            roll_result = DiceRoller.roll_simple(dice_expression)
             await ctx.send(f"You rolled: {roll_result}")
         except ValueError as e:
             await ctx.send(f"Roll failed: {e}")

src/dice/dice.py

@@ -1,8 +1,31 @@
+import dataclasses
 import typing
 
 from src.dice.parser import DieParser
 
 
+@dataclasses.dataclass
+class DieRollResult:
+    """
+    DieRoll is the result of a die roll.
+    """
+
+    result: int
+    modifier: int
+    rolls: typing.List[int]
+    type: str
+
+
+@dataclasses.dataclass
+class DieExpressionResult:
+    """
+    DiceResult is the result of a dice roll expression.
+    """
+
+    total: int
+    dies: typing.List[DieRollResult]
+
+
 class DiceRoller:
     """
     DiceRoller is a simple class that allows you to roll dices.
@@ -10,45 +33,28 @@ class DiceRoller:
     A die can be rolled using the following expression:
     - 1d20 will roll a 20-faceted die and output the result a random number between 1 and 20.
     - 1d100 will roll a 100 faceted die.
-    - 2d20 will roll a two d20 dies and multiply the result by two.
-    - 2d20+5 will roll a two d20 dies and multiply the result by two and ads 5.
+    - 2d20 will roll two d20 dies and multiply the result by two.
+    - 2d20+5 will roll two d20 dies add them together then add 5 to the result.
     """
 
     _parser = DieParser.create()
 
     @staticmethod
-    def roll(expression: str, *, advantage: typing.Optional[bool] = None) -> int:
+    def roll_simple(expression: str) -> int:
         """
         Roll die and return the result.
         :param expression: The die expression.
-        :param advantage: Optionally, rolls a die with advantage or disadvantage.
         :return: The die result.
         """
-        if advantage is None:
-            return DiceRoller._parser.parse(expression)
-        elif advantage is True:
-            return DiceRoller.roll_with_advantage(expression)
-        elif advantage is False:
-            return DiceRoller.roll_with_disadvantage(expression)
+        result = DiceRoller._parser.parse(expression)
+        return result.get("total")
 
     @staticmethod
-    def roll_with_advantage(expression: str) -> int:
+    def roll(expression: str) -> DieExpressionResult:
         """
-        Roll two dies and return the highest result.
+        Roll die and return the DiceResult.
         :param expression: The die expression.
         :return: The die result.
         """
-        one = DiceRoller._parser.parse(expression)
-        two = DiceRoller._parser.parse(expression)
-        return max(one, two)
-
-    @staticmethod
-    def roll_with_disadvantage(expression: str) -> int:
-        """
-        Roll two dies and return the lowest result.
-        :param expression: The die expression.
-        :return: The die result.
-        """
-        one = DiceRoller._parser.parse(expression)
-        two = DiceRoller._parser.parse(expression)
-        return min(one, two)
+        result = DiceRoller._parser.parse(expression)
+        return DieExpressionResult(**result)

src/dice/parser.py

@@ -8,12 +8,12 @@ DIE_GRAMMAR = """
     @@grammar::Die
     @@whitespace :: None
 
-    start = die:die $;
+    start = die:die ~ {op:operator die:die} $;
 
     die = [number_of_dies:number] die_type:die_type die_number:number [modifier:die_modifier];
     die_modifier = op:operator modifier:number;
 
-    operator = '+' | '-';
+    operator = '+' | '-' | 'adv' | 'dis';
 
     die_type = 'd' | 'zd';
 
@@ -35,7 +35,7 @@ class DieParser:
     def create() -> "DieParser":
         return DieParser()
 
-    def parse(self, expression: str) -> int:
+    def parse(self, expression: str) -> dict:
         """
         Parses the die expression and returns the result.
         """

src/dice/semantics.py

@@ -1,4 +1,6 @@
+import copy
 import random
+from collections import deque
 from tatsu.ast import AST
 
 
@@ -8,7 +10,32 @@ class DieSemantics:
         return int(ast)
 
     def start(self, ast):
-        return ast.get("die").get("result")
+        die = ast.get("die")
+        if isinstance(die, dict):
+            return {"total": die.get("result"), "dies": [die]}
+        elif isinstance(die, list):
+            return_value = {"total": 0, "dies": copy.deepcopy(die)}
+            operators = deque(ast.get("op", []))
+
+            die_results = deque(map(lambda x: x.get("result"), die))
+            # Note: we may need to use a dequeue, the ops are quite inefficient.
+            while len(die_results) != 1:
+                left = die_results.popleft()
+                right = die_results.popleft()
+                operator = operators.popleft()
+                total = 0
+                if operator == "+":
+                    total = left + right
+                if operator == "-":
+                    total = left - right
+                if operator == "adv":
+                    total = max(left, right)
+                if operator == "dis":
+                    total = min(left, right)
+                die_results.appendleft(total)
+
+            return_value["total"] = die_results.pop()
+            return return_value
 
     def die(self, ast):
         if not isinstance(ast, AST):
@@ -34,8 +61,8 @@ class DieSemantics:
 
         return {
             "result": max(sum(rolls) + die_modifier, minimum_value_for_die),
-            "die_type": die_type,
-            "roll_history": rolls,
+            "type": die_type,
+            "rolls": rolls,
             "modifier": die_modifier,
         }
 

tests/dice/test_dice.py

@@ -48,10 +48,10 @@ def dice_roller():
         ("1d 4 +0", 1, 4),
     ],
 )
-def test_die_roller_die_roll(expression, range_min, range_max, dice_roller):
+def test_die_roller_die_roll_simple(expression, range_min, range_max, dice_roller):
     # let the dies roll...
     for i in range(100):
-        result = dice_roller.roll(expression)
+        result = dice_roller.roll_simple(expression)
         assert range_min <= result <= range_max
 
 
@@ -95,10 +95,10 @@ def test_die_roller_die_roll(expression, range_min, range_max, dice_roller):
         ("1zd 4 +0", 0, 4),
     ],
 )
-def test_die_roller_zero_die_roll(expression, range_min, range_max, dice_roller):
+def test_die_roller_zero_die_roll_simple(expression, range_min, range_max, dice_roller):
     # let the dies roll...
     for i in range(100):
-        result = dice_roller.roll(expression)
+        result = dice_roller.roll_simple(expression)
         assert range_min <= result <= range_max
 
 
@@ -119,14 +119,11 @@ def test_die_roller_zero_die_roll(expression, range_min, range_max, dice_roller)
 )
 def test_die_roller_die_parsing_fail(expression, dice_roller):
     with pytest.raises(ValueError):
-        dice_roller.roll(expression)
+        dice_roller.roll_simple(expression)
 
 
-def test_die_roller_roll_with_advantage(dice_roller):
-    assert 1 <= dice_roller.roll_with_advantage("d20") <= 20
-    assert 1 <= dice_roller.roll("d20", advantage=True) <= 20
-
-
-def test_die_roller_roll_with_disadvantage(dice_roller):
-    assert 1 <= dice_roller.roll_with_advantage("d20") <= 20
-    assert 1 <= dice_roller.roll("d20", advantage=False) <= 20
+def test_die_roller_roll(dice_roller):
+    for i in range(100):
+        result = dice_roller.roll("d20 + d20 adv d20+5 dis d12+3")
+        assert 1 <= result.total <= 15
+        assert len(result.dies) == 4