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.
This behavior became broken again after switching away from the
macro-based command parsing. The bot would return any non !command
message as an error, which would cause it to read more messages, and
return those as errors, until finally the matrix SDK would throw up.
Command parser now more properly handles empty messages and
non-commands, but we also simply abort processing if the incoming
message doesn't start with an exclamation point.
projectmoon
Taylor C. Richberger