The Blots Programming Language

The most recent version of Blots is 0.7.1, released on 9/16/2025.

If you're on macOS, the recommended way to install the latest version of Blots is with Homebrew:

brew install paul-russo/tap/blots

You can also install Blots 0.7.1 for both Linux and macOS by running the following command:

curl --proto '=https' --tlsv1.2 -LsSf https://github.com/paul-russo/blots-lang/releases/download/v0.7.1/blots-installer.sh | sh

Here's a quick example of how you could use Blots to interactively compute some basic statistics about the weather forecast for the next 7 days in Denver, CO:

First, we'll grab the forecast for Denver from the National Weather Service API and pass the response to Blots as an input. We'll also use the --output flag to provide a filename to write the outputs to (this is optional; if we didn't provide a filename, the outputs would just be written to stdout):

blots --input "$(curl -s https://api.weather.gov/gridpoints/BOU/63,62/forecast)" --output weather.json

Since we provided neither a source file nor some inline code, Blots will open up in interactive mode. We can now use the inputs record to access the forecast data and bind it to a name (forecasts):

> forecasts = inputs.properties.periods
= [{detailedForecast: "A chance of showers and thunderstorms... (truncated)

Next, we'll grab the temperatures from the forecasts by mapping over the list. We can use Blots's via operator to apply a function to each element of the list. Our function will take just the forecasted tempeature for that period and return it, so the whole expression evaluates to a new list containing only the temperatures:

> temps = forecasts via forecast => forecast.temperature
= [52, 71, 49, 73, 49, 80, 53, 85, 56, 83, 56, 83, 54, 86]

Now we can compute the average temperature using Blots's avg function. We want to include this in our output file `weather.json`, so we'll use the output keyword to bind the result to a name and record it in the outputs:

> output average = avg(temps)
= 66.42857142857143
[output 'average' recorded]

Let's do the same for the minimum and maximum temperatures:

> output minimum = min(temps)
= 49
[output 'minimum' recorded]
> output maximum = max(temps)
= 86
[output 'maximum' recorded]

We can now exit Blots (by typing exit or hitting Ctrl + c). Let's take a look at the output file:

cat weather.json
{"average":66.42857142857143,"minimum":49.0,"maximum":86.0}