Synopsis

rolldice, a very simple interpreter for rolling dice.

A toy project that uses GNU flex and GNU bison, released under the WTFPLv2.

Usage

• rolldice (interactive REPL mode)
• rolldice < rolls.txt (batch mode)

Syntax

Rolling dice:

• dY to roll one Y-sided die
• XdY to roll X Y-sided die and add the result

Rolling modifiers (multiple can be specified in any order after the roll):

• hZ drop Z highest results
• lZ drop Z lowest results
• rZ reroll all Z once
• rrZ reroll all Z recursively
• rhZ reroll Z highest results
• rlZ reroll Z lowest results

Simple math operators are also supported:

• + for addition.
• - for substraction.
• * for multiplication.
• / for integer division (rounds up).
• \ for integer division (rounds down).
• (…) for forcing precedence.

Nested operations are also supported:

• (d4)d4 will roll a d4, then roll the rolled amount of d4s.
• (d6)d(d12), etc.

Examples

• d6 roll a six-sided die.

• 2d10 roll two ten-sided die and add the result.

• d20+7 roll a d20 and add 7 to the result.

• 4d6l1 roll 4d6 and drop the lowest die.

• 3d6r1 roll 3d6 and reroll ones.

• 5d6rl2 roll 5d6 and reroll the two lowest dice.

• 4d6l1r1 roll 4d6, drop the lowest result, reroll ones

• 4d6r1l1 roll 4d6, reroll ones, drop the lowest result

• (2d8+3)/2 roll 2d8+3, divide the result by 2, round up

• (4d4+1)\2 roll 4d4+1, divide the result by 2, round down

Todo/Ideas

• Critical hit/fumble
• Advantage/disadvantage
• User functions/macros
• Comparison operators, control logic