The Kyma Language for Sound Design, Version 4.5

Booleans
Alternatively, you can place expressions to be evaluated within curly braces:
#({2+5} #(abc))
A boolean is one of two values: true or false. There are two boolean literals:
true
and
false
Some examples of boolean expressions include:
(2 + 2) = 5
i >= 2
Logical Operations
Blocks
aSet isEmpty
file atEnd
Boolean expressions can be combined using the logical operators AND and OR.
There are two different kinds of logical operations for both AND and OR. One type evaluates only as
much of the expression as is necessary to determine whether the entire expression is true or false; in this
type of expression, the second alternative is placed within a block, for example:
anArray isEmpty or: [(anArray at: 1) = 0]
aStream atEnd not and: [aStream next == ‘a’]
The other type always evaluates both arguments of the expression; in this type of expression, the two arguments
are separated by an ampersand for AND or a vertical bar for OR, for example:
t > 2.5 & (t < 550.0)
r next > 0.5 | (r next = 0.0)
The following expression is true if anArray is empty or if its first entry is 0. If the first expression is true,
then the expression within square brackets is not evaluated, since the entire expression is true if either of
the subexpressions is true. By using this form of the OR, you are protected against trying to access an
empty array.
anArray isEmpty or: [(anArray at: 1) = 0]
In the next example, the OR operation is represented by a vertical bar. Both expressions are evaluated no
matter what the value of the first expression. In this example, the message next returns the next value in a
stream of values. It also has the side effect of advancing the pointer into the stream. In cases where an expression
has a side-effect, you may want to evaluate both expressions even when the first is true.
anArray isEmpty | (aStream next = 0)
In the following example of the AND operator, the second expression is evaluated only if the first expression
is true. In the case of this example, you wouldn’t want to try accessing the ith position of anArray
unless you were sure that anArray had at least i positions in it.
(anArray size >= i) and: [(anArray at: i) = 10]
The ampersand operator is an AND in which both expressions are evaluated even if the first is false. In
this particular case, the message removeFirst returns the first element of aCollection, but it also has
the side effect of changing aCollection by removing the first element.
i > 10 & (aCollection removeFirst = 0)
A block is a deferred sequence of instructions having the form
518