RNG Query

CLI to use pseudorandomness the easy way and help me with decision paralysis

rq "a, b, c"              # choose a, b or c at random
rq "2d20"                 # roll 2 20 sided dice and sum the result
rq "[1, 10)"              # random decimal between 1 and 10, not including 10
rq "a, b, c / shuffle"    # shuffle the list
rq "coin, d6, -5..5 / 2"  # 2 values from the list and evaluate the result
cat file.txt | rq "/10o"  # choose 10 lines keeping original order

CLI

# Install it
cargo install rng-query

# Basic usage
rq "your query"   # run a quick query
rq --help         # see help message

There are also precompiled binaries in the github releases.

With the CLI you can read entries from stdin. Each line will be an entry, but just as text. You can pass the -e flag to evaluate each line as a separate expression. Then the query you execute will have the entries of stdin already included.

Input files will be stored in memory with a little overhead. Therefore, very large files may use a lot of memory. It is possible to improve this, but it's currently not in the scope of this project.

Syntax

A query is a selection of entries from a list with options. Each entry can be an expression or just text.

Entries are separated by a comma , or a new line. Then, everything after / until the end of the query will be options.

Options

If the input ends without options, / 1 is the default.

The options have the format / [n] [flags], where flags are just chars. Spaces are ignored. [n] is a non negative integer or all. If not given, it's 1.

Flags are single characters, they can be separated with spaces and cannot repeat. The flags are:

• r: allow options to repeat.
• o: keep the original order when choosing multiple.

There are some presets with better names for the operation:

• / shuffle same as / all
• / list same as / all o

Expressions

Each entry can be an expression, there are currently 4 expressions:

• Subqueries
• Intervals
• Dice
• Coin

Subqueries

Another query can be nested between { and }. When selected, will be evaluated the same as the root one. This allows to express a bit more of a bias towards some options.

For example:

"a, {b, c}"  # a query where 'a' has a 50% chance of being selected and 'b'
              # and 'c' split the other 50%, so 25% each

Intervals

Choose a random number. Between [ or ( and ] or ). The bounds are determined by the enclosing character. Square brackets include the bound and parenthesis dont.

Inside 2 numbers represent the lower and upper limit. If they are separated by a comma , the will be treated as floats. If they are separated with .. it will be floats if any of them are. Some examples are:

"(1, 5)"   # decimal between 1 and 5, not included
"(1, 5]"   # decimal between 1 and 5, 5 included
"[1..5]"   # integer between 1 and 5
"[1..5.5)" # decimal betwen 1 and 5.5, not included

An alternative syntax just for integers is a range like this:

"1..5"  # integer between 1 and 4
"1..=5" # integer between 1 and 5

Negatives number are supported both in integers and floats.

Open/half-open intervals are not supported because I don't know a good way to handle max/min values.

Dice

Roll dice with a D&D like syntax.

[amount]d<sides>[!][select][modifier*]

d6        => roll a 6 sided die
2d6       => 2 x 6s dice and sum
2d20k     => 2 x 20s dice and keep the highest

Sides can also be % which equals to 100.

! is exploding. If rolled the maximum value, roll another die.

For select you can add <k|d>[h|l][n]. If n is not given, it's 1. You can have:

• k or kh to keep the highest n dice.
• kl to keep the lowest n dice.
• d or dl to drop the lowest n dice.
• dh to drop the n highest dice.

The modifer is <+|->[m] to add or subtract a value to the total result. You can specify more than one.

When evaluated you will get the sum of all the dice rolls.

There are many more ways to expand this dice notation, but please don't use this tool for your D&D game, roll real dice! If you really really really think more modifiers can be useful, submit an issue.

Coin

Toss a coin. Simple, just write coin. At the end it's equivalent to a subquery like { heads, tails }.

Notes on pseudorandomness

Currently, randomness should be statistically valid, but NOT cryptographically secure. If you need this to change, submit an issue.