Dice

[num]d[sides] [keep modifier] [modifier]

num is the number of the dices to roll. (Optional)
sides is the number of sides of the dice. (Required)
keep_modifier is in the form of kh or kl followed by a number. This only keeps either the highest or lowest dice. (Optional)
modifier is in the form of +, -, >, <, >= or <= followed by a number. In case of + or -, the number is added or subtracted to the total. In case of >, <, >= or <=, the dice roll is checked against the condition and counted as a success if it matches it.(Optional)

Examples:
1d6
2d10 + 5
3d20 kh2 - 2
2d20 kl 2
10d6 >= 6
6d20 < 10