Series 2600B System SourceMeter® Instrument Reference Manual
Section 6: Instrument programming
2600BS-901-01 Rev. B / May 2013
6-19
Example: Concatenation
print(2 .. 3)
print("Hello " .. "World")
23
Hello World
Operator precedence
Operator precedence in Lua follows the order below (from higher to lower priority):
•
^
(exponentiation)
•
not, -
(unary)
•
*, /
•
+,
−
•
..
(concatenation)
•
<, >, <=, >=, ~=, ==
•
and
•
or
You can use parentheses to change the precedences in an expression. The concatenation ("
..
") and
exponentiation ("
^
") operators are right associative. All other binary operators are left associative. The
examples below show equivalent expressions.
Equivalent expressions
r offset < testValue/2+0.5
=
(r offset) <
((testValue/2)+0.5)
3+reading^2*4
=
3+((reading^2)*4)
Rdg < maxRdg and lastRdg <=
expectedRdg
=
(Rdg < maxRdg) and (lastRdg <=
expectedRdg)
-reading^2
=
-(reading^2)
reading^testAdjustment^2
=
reading^(testAdjustment^2)
Conditional branching
Lua uses the
if
,
else
,
elseif
,
then
, and
end
keywords to do conditional branching.
Note that in Lua,
nil
and
false
are
false
and everything else is
true
. Zero (0) is
true
in Lua.
Содержание System SourceMeter 2601B
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