1.3.1. - spec as a Calculator
In some respects, the spec user interface behaves like a BASIC language interpreter that uses the C language syntax. For example, you can easily print strings and the results of arithmetic expressions:
1.FOURC> p 2+2, sqrt(3), "2^16 =", 1<<16
4 1.73205 2^16 = 65536 2.FOURC>
(The
p
macro is defined as
print,
a built-in command.)
You do not need to search for your calculator, as
all the standard operators and functions are available.
The arithmetic operators (
= , * , / , % , + , - , ++ , --, += , -= , *= , /= , %= ), the relational
operators (> , < , <= , >= , == , != ), the boolean
operators (! , && , || ), the bitwise
operators (>> , << , ~ , & , ^ , | , >>= , <<= , &= , ^= , |= ) and the ternary
operator (?:)
are all available.
Parentheses can be used for grouping within expressions.
See the
Reference Manual
for a description of all the operators
and their rules of precedence.
The most useful standard C math functions are included, such as
sin(), cos(), tan(), asin(), acos(), atan(), exp(), log(), log10(), pow(), sqrt(), and
fabs(). Conversions functions such as
deg() and
rad() convert between degrees and radians, while
bcd() and
dcb() convert between decimal and binary-coded decimal.
A
rand() function to return random numbers is also provided.
Numbers can be entered in decimal, octal or hexadecimal notation, just as in C.
1.FOURC> p 100, 0100, 0x100
100 64 256 2.FOURC>
Special string functions also exist. The
date()
function provides
the current date and time as a string:
1.FOURC> p date()
Mon Feb 15 02:13:13 1994 2.FOURC>
The
date() function
can also take an argument that is the number of seconds
from the UNIX epoch.
1.FOURC> p date(1e9)
Sat Sep 8 21:46:40 2001 2.FOURC> p date(0)
Wed Dec 31 19:00:00 1969 3.FOURC> p int(time()), date(time())
729760917 Mon Feb 15 02:21:57 1994 4.FOURC>
The second example shows the (Eastern Standard Time) moment of the UNIX epoch. The function
time() returns the number of
seconds
since that moment, including a fractional part with
a resolution determined by the system clock.
The difference of subsequent calls to
time() can, for example, give a reasonable elapsed time
for each point in a scan.
The function
input() reads a string from the keyboard.
An optional argument will be printed first.
For example, a macro or command file
might prompt you for information:
1.FOURC> TITLE = input("Please enter a title: ")
Please enter a title: Au (001) Sample #1
2.FOURC> Other string functions such as
index(),
substr(), length(s)
and
sprintf(format, [args])
are also available.
See the
Reference Manual
for details.