This commit refactors the parsing and rolling for the dice pool system
to prepare for support of user variables. The nom parser was dropped
in favor of the easier-to-understand combine parser in most parts of
the code.
A breaking change was introduced into the dice pool syntax to allow
for proper expressions and variables. The syntax is now
"modifiers:pool-amount", e.g. "n:gnosis+8". The simple single-number
syntax with no modifiers is also still understood.
Dice pool expressions are translated into a Vec of "Amount" objects,
stored by the DicePool struct. They have an operator (+ or -) and
either a number or variable name. When the dice pool is rolled, this
list of Amonuts are is collapsed into a single number that is rolled,
as it was before the refactor.
The following changes were made to the dice rolling code:
- Store Vec<Amount> on DicePool instead of single number to roll.
- New struct RolledDicePool to store result of a dice pool roll.
- Remove Display trait from DicePool, move it over to RolledDicePool.
- Separate extra dice pool info into DicePoolModifiers.
- DicePoolModifiers is shared between DicePool and RolledDicePool.
- Dice parsing and rolling now return standard Result objects.
This commit does NOT enable support of actually using variables. Any
dice pool roll containing a variable will result in an eror.
The command parser was also rewritten to use combine and rely on the
standard Result pattern.
projectmoon