NAME¶
mathop - Mathematical operators as Tcl commands
SYNOPSIS¶
package require
Tcl 8.5
::tcl::mathop::! number
::tcl::mathop::~ number
::tcl::mathop::+ ?
number ...?
::tcl::mathop::- number ?
number ...?
::tcl::mathop::* ?
number ...?
::tcl::mathop::/ number ?
number ...?
::tcl::mathop::% number number
::tcl::mathop::** ?
number ...?
::tcl::mathop::& ?
number ...?
::tcl::mathop::| ?
number ...?
::tcl::mathop::^ ?
number ...?
::tcl::mathop::<< number number
::tcl::mathop::>> number number
::tcl::mathop::== ?
arg ...?
::tcl::mathop::!= arg arg
::tcl::mathop::< ?
arg ...?
::tcl::mathop::<= ?
arg ...?
::tcl::mathop::>= ?
arg ...?
::tcl::mathop::> ?
arg ...?
::tcl::mathop::eq ?
arg ...?
::tcl::mathop::ne arg arg
::tcl::mathop::in arg list
::tcl::mathop::ni arg list
DESCRIPTION¶
The commands in the
::tcl::mathop namespace implement the same set of
operations as supported by the
expr command. All are exported from the
namespace, but are not imported into any other namespace by default. Note that
renaming, reimplementing or deleting any of the commands in the namespace does
not alter the way that the
expr command behaves, and nor does
defining any new commands in the
::tcl::mathop namespace.
The following operator commands are supported:
~ ! + - *
/ % ** & |
^ >> << == eq
!= ne < <= >
>= in ni
MATHEMATICAL OPERATORS¶
The behaviors of the mathematical operator commands are as follows:
- ! boolean
- Returns the boolean negation of boolean, where
boolean may be any numeric value or any other form of boolean value
(i.e. it returns truth if the argument is falsity or zero, and falsity if
the argument is truth or non-zero).
- + ?number ...?
- Returns the sum of arbitrarily many arguments. Each
number argument may be any numeric value. If no arguments are
given, the result will be zero (the summation identity).
- - number ?number ...?
- If only a single number argument is given, returns
the negation of that numeric value. Otherwise returns the number that
results when all subsequent numeric values are subtracted from the first
one. All number arguments must be numeric values. At least one
argument must be given.
- * ?number ...?
- Returns the product of arbitrarily many arguments. Each
number may be any numeric value. If no arguments are given, the
result will be one (the multiplicative identity).
- / number ?number ...?
- If only a single number argument is given, returns
the reciprocal of that numeric value (i.e. the value obtained by dividing
1.0 by that value). Otherwise returns the number that results when the
first numeric argument is divided by all subsequent numeric arguments. All
number arguments must be numeric values. At least one argument must
be given.
Note that when the leading values in the list of arguments are integers, integer
division will be used for those initial steps (i.e. the intermediate results
will be as if the functions
floor and
int are applied to them,
in that order). If all values in the operation are integers, the result will
be an integer.
- % number number
- Returns the integral modulus of the first argument with
respect to the second. Each number must have an integral value.
Note that Tcl defines this operation exactly even for negative numbers, so
that the following equality holds true:
( x / y) * y == x - (x % y)
- ** ?number ...?
- Returns the result of raising each value to the power of
the result of recursively operating on the result of processing the
following arguments, so “ ** 2 3 4” is the same as
“ ** 2 [** 3 4]”. Each number may be any numeric
value, though the second number must not be fractional if the first is
negative. If no arguments are given, the result will be one, and if only
one argument is given, the result will be that argument. The result will
have an integral value only when all arguments are integral values.
COMPARISON OPERATORS¶
The behaviors of the comparison operator commands (most of which operate
preferentially on numeric arguments) are as follows:
- == ?arg ...?
- Returns whether each argument is equal to the arguments on
each side of it in the sense of the expr == operator (i.e.,
numeric comparison if possible, exact string comparison otherwise). If
fewer than two arguments are given, this operation always returns a true
value.
- eq ?arg ...?
- Returns whether each argument is equal to the arguments on
each side of it using exact string comparison. If fewer than two arguments
are given, this operation always returns a true value.
- != arg arg
- Returns whether the two arguments are not equal to each
other, in the sense of the expr != operator (i.e., numeric
comparison if possible, exact string comparison otherwise).
- ne arg arg
- Returns whether the two arguments are not equal to each
other using exact string comparison.
- < ?arg ...?
- Returns whether the arbitrarily-many arguments are ordered,
with each argument after the first having to be strictly more than the one
preceding it. Comparisons are performed preferentially on the numeric
values, and are otherwise performed using UNICODE string comparison. If
fewer than two arguments are present, this operation always returns a true
value. When the arguments are numeric but should be compared as strings,
the string compare command should be used instead.
- <= ?arg ...?
- Returns whether the arbitrarily-many arguments are ordered,
with each argument after the first having to be equal to or more than the
one preceding it. Comparisons are performed preferentially on the numeric
values, and are otherwise performed using UNICODE string comparison. If
fewer than two arguments are present, this operation always returns a true
value. When the arguments are numeric but should be compared as strings,
the string compare command should be used instead.
- > ?arg ...?
- Returns whether the arbitrarily-many arguments are ordered,
with each argument after the first having to be strictly less than the one
preceding it. Comparisons are performed preferentially on the numeric
values, and are otherwise performed using UNICODE string comparison. If
fewer than two arguments are present, this operation always returns a true
value. When the arguments are numeric but should be compared as strings,
the string compare command should be used instead.
- >= ?arg ...?
- Returns whether the arbitrarily-many arguments are ordered,
with each argument after the first having to be equal to or less than the
one preceding it. Comparisons are performed preferentially on the numeric
values, and are otherwise performed using UNICODE string comparison. If
fewer than two arguments are present, this operation always returns a true
value. When the arguments are numeric but should be compared as strings,
the string compare command should be used instead.
BIT-WISE OPERATORS¶
The behaviors of the bit-wise operator commands (all of which only operate on
integral arguments) are as follows:
- ~ number
- Returns the bit-wise negation of number.
Number may be an integer of any size. Note that the result of this
operation will always have the opposite sign to the input
number.
- & ?number ...?
- Returns the bit-wise AND of each of the arbitrarily many
arguments. Each number must have an integral value. If no arguments
are given, the result will be minus one.
- | ?number ...?
- Returns the bit-wise OR of each of the arbitrarily many
arguments. Each number must have an integral value. If no arguments
are given, the result will be zero.
- ^ ?number ...?
- Returns the bit-wise XOR of each of the arbitrarily many
arguments. Each number must have an integral value. If no arguments
are given, the result will be zero.
- << number number
- Returns the result of bit-wise shifting the first argument
left by the number of bits specified in the second argument. Each
number must have an integral value.
- >> number number
- Returns the result of bit-wise shifting the first argument
right by the number of bits specified in the second argument. Each
number must have an integral value.
LIST OPERATORS¶
The behaviors of the list-oriented operator commands are as follows:
- in arg list
- Returns whether the value arg is present in the list
list (according to exact string comparison of elements).
- ni arg list
- Returns whether the value arg is not present in the
list list (according to exact string comparison of elements).
EXAMPLES¶
The simplest way to use the operators is often by using
namespace path to
make the commands available. This has the advantage of not affecting the set
of commands defined by the current namespace.
namespace path { ::tcl::mathop ::tcl::mathfunc}
# Compute the sum of some numbers
set sum [ + 1 2 3]
# Compute the average of a list
set list {1 2 3 4 5 6}
set mean [ / [+ {*}$list] [double [llength $list]]]
# Test for list membership
set gotIt [ in 3 $list]
# Test to see if a value is within some defined range
set inRange [ <= 1 $x 5]
# Test to see if a list is sorted
set sorted [ <= {*}$list]
SEE ALSO¶
expr(3tcl), mathfunc(3tcl), namespace(3tcl)
KEYWORDS¶
command, expression, operator