Language Extensions
These language extensions are provided in the following namespace URI:
http://www.juiblex.co.uk/ns/libxexpr
People using this namespace are encouraged to use the libxexpr namespace
prefix.
Function <pi>
Synopsis
<pi> returns the value of π.
Arguments
<pi> takes no arguments.
Return Values
<pi> returns the value of π.
<libxexpr:pi/> ≅ <float>3.14</float>
Function <sin>
Synopsis
<sin> computes the sine function.
Arguments
<sin> takes one argument: x. If no argument is given, an error
occurs.
Return Values
<sin> returns the sine of its argument, given in radians.
If the argument does not evaluate to a finite number,
<sin> returns an indeterminate result.
<libxexpr:sin>
<divide>
<libxexpr:pi/>
2
</divide>
</libxexpr:sin> --> <float>1</float>
Function <atan>
Synopsis
<atan> computes the arc tangent function.
Arguments
<atan> takes two arguments: x and y. The y argument defaults to
1. If the x argument is missing, an error occurs.
Return Values
<atan> returns the principal value of the arc tangent of its
argument(s) in radians. If either argument is indeterminate,
the result is also indeterminate.
If two arguments are given, <atan> returns the arc tangent of
y/x, using the signs of the two arguments to determine the quadrant
of the result which will be in the range [-π, π]. If both arguments
are 0, the result will also be 0.
If only one argument is given, <atan> returns the arc tangent of
its argument. The result will be in the range [-π/2, π/2].
<libxexpr:atan>1 0</libxexpr:atan> --> <float>0</float>
Function <exp>
Synopsis
<exp> computes the base-e exponential function.
Arguments
<exp> takes zero or one argument: x.
Return Values
<exp> returns the value of e (the base of natural logarithms)
raised to the power of its argument (or just e if no argument is
supplied). If the argument does not evaluate to a finite number,
<exp> returns an indeterminate result.
<libxexpr:exp>2</libxexpr:exp> ≅ <float>7.389</float>
Function <log>
Synopsis
<log> computes the natural logarithmic function.
Arguments
<log> takes one argument: x. If no argument is given, an error
occurs.
Return Values
<log> returns the natural logarithm of its argument.
If the argument does not evaluate to a positive finite number,
<log> returns an indeterminate result.
<libxexpr:log>
<libxexpr:exp>2</libxexpr:exp>
</libxexpr:log> --> <float>2</float>
Function <pow>
Synopsis
<pow> computes the value of its first argument raised to the
power of its second argument.
Arguments
<pow> takes two arguments: x and y. If fewer arguments are
given, an error occurs.
Return Values
<pow> returns the value of x (its first argument) raised to the
power of y (its second argument).
If x is a finite value less than 0, and y is a finite non-integer,
<pow> returns an indeterminate result.
If the result overflows, <pow> returns an indeterminate result.
If result underflows, and is not representable, 0 is returned.
Except as specified below, if either argument is indeterminate,
the result is also indeterminate.
If x is 1, the result is 1 (even if y is indeterminate).
If y is 0, the result is 1 (even if x is indeterminate).
If x is 0, and y is an odd integer greater than 0, the result is 0.
If x is 0, and y greater than 0 and not an odd integer, the result
is 0.
If x is 0, and y is less than 0,
<pow> returns an indeterminate result.
<libxexpr:pow>10 2</libxexpr:pow> --> <float>100</float>