Fundamental Expressions ​

Note: The syntax for eg. dictionaries is documented in Data Types.

Arithmetic ​

Boolean Operations ​

cd dir1 && mkdir dir2
echo(x and y)

cd dir1 && mkdir dir2
echo(x and y)

Comparisons ​

Blocks ​

A block is a single expression that can contain several other expressions that are evaluated consecutively. The value of a block is always the value of the last expression in that block.

let x = {
    "one"
    "two"
}

assert(x == "two")

let x = {
    "one"
    "two"
}

assert(x == "two")

Pipes ​

Pipe expressions are written with the syntax value | receiver where value is the value that should be sent to the receiver function or program. The behaviour is different depending on whether the receiving side is a function call or a program invocation.

For program invocations, it is also possible to specify which output stream should be redirected, using |err to only redirect stderr or |all to redirect both stdout and stderr.

With Function Calls ​

When the receiving side is a function call, the pipe expression's value is prepended to the call's argument list, meaning it becomes the first argument of the call.

"1,2,3" | split(",")

"1,2,3" | split(",")

is equivalent to

split("1,2,3", ",")

split("1,2,3", ",")

With Program Invocations ​

When the receiving side is a program invocation, the pipe expression's value is sent to the standard input of the process created by the invocation. This behaviour can be compared to how pipes work in Bash.

cat file.txt | grep line
some-program |err write errors.txt
another-program |all write all-output.txt

cat file.txt | grep line
some-program |err write errors.txt
another-program |all write all-output.txt