Expressions
Expressions
are the building blocks of the CFML language. In its most basic form,
an expression is nothing more than a single element such as
1
, test
,
MyVar
, or CHR(54)
. Compound
expressions let you to evaluate data that is acted upon by operators.
For example, 1*10
is a mathematical expression
that evaluates to 10
. The values
1
and 10
are both data, while
the asterisk (*
) is considered an operator. On the
other end of the spectrum, expressions can be complex, consisting of
one or more subexpressions:
<CFSET x = 1+(10 MOD (3 * (11 - ACOS(-1))))>
Operators
Operators allow you to perform
calculations and make comparisons between expressions. In other
words, they allow you to combine simple expressions to form ones that
are more complex. For example, <CFSET x = 10*(3+2)>
uses the asterisk (*
) as an
operator to multiply 10 by the sum of another expression that uses
the plus (+
) operator to add 3 and 2. There are
four types of operators available in ColdFusion:
- Arithmetic
Performs arithmetic operations such as sign changes, addition, subtraction, etc., on numeric values.
- Comparison
Compares two values and return a Boolean
True
/False
.- String
There is only one string operator in the CFML language. The ampersand (
&
) concatenates strings.- Boolean
Also known as logical operators, Boolean operators perform connective and negation operations and return Boolean
True
/False
values.
Table 2-2 lists the operators available in ColdFusion by order of precedence (P).
Table 2-2. ColdFusion ...
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