Language Guide

CHAPTER 6
Expressions
176 Operations
RECORD
A record contains another record if all the properties in the record to the
right of the operator are included in the record to the left, and the values
of properties in the record to the right are equal to the values of the correspon-
ding properties in the record to the left. A record is contained by another record
if all the properties in the record to the left of the operator are included in the
record to the right, and the values of the properties in the record to the left
are equal to the values of the corresponding properties in the record to the
right. The order in which the properties appear does not matter. For example,
{ name:"Eric", mileage:"8000", description:"fast"} 
contains { description:"fast", name:"Eric" }
is true.
STRING
A string contains another string if the characters in the string to the right of the
operator are equal to any contiguous series of characters in the string to the left
of the operator. For example,
"operand" contains "era"
is true, but
"operand" contains "dna"
is false.
A string is contained by another string if the characters in the string to the left
of the operator are equal to any series of characters in the string to the right of
the operator. For example, this statement is true:
"era" is contained by "operand"