Wiley-World.of.Warcraft.Programming.A.Guide.and.Reference.for.Creating.WoW.Addons

Chapter 6 ■ Lua Standard Libraries 105optional numerical argument—init—specifies where to start the search; itsdefault value is 1 and may be negative. A value of true as a fourth, optionalargument, plain, turns off the pattern matching facilities, so the functiondoes a plain ‘‘find substring’’ operation, with no characters in pattern beingconsidered ‘‘magic.’’ Note that if plain is given, init must also be given.If the pattern has captures, then in a successful match the captured valuesare also returned, after the two indices.Math LibraryThe math library provides an interface to several standard math functions andconstants. Table 6-8 describes some of the more common functions in the mathlibrary. (It is not a full listing of the library; for that, please consult a properLua reference, which includes a full set of trigonometric functions such asmath.cos, math.sin, math.tan, and so on.)Table 6-8: Math FunctionsFUNCTION DESCRIPTION EXAMPLEmath.abs(x) Returns the absolutevalue of x.> print(math.abs(13))13> print(math.abs(-13))13math.ceil(x)math.deg(x)math.exp(x)math.floor(x)Returns the smallestinteger larger than orequal to x.Returns the angle x(given in radians) indegrees.Returns the value of themathematical constanteraisedtothex power.Returns the largestinteger smaller than orequal to x.> print(math.ceil(1.03))2> print(math.cell(13))13> print(math.cell(17.99))18> print(math.deg(math.pi))180> print(math.deg(math.pi * 2.5))450> print(math.exp(27))532048240601.8> print(math.floor(1.03))1> print(math.floor(13.0))13> print(math.floor(17.99)17Continued