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

102 Part I ■ Learning to ProgramPattern AnchorsA pattern is quite literally a sequence of characters to be matched. Using ˆ atthe beginning of a pattern can match the beginning of a string, whereas using$ at the end of a pattern can match the end of a string. When used anywhereelse in the pattern, these strings will match their literal equivalent. Anchorscanbeusedtomakeapatternmoreexplicit.Pattern ExamplesTable 6-7 illustrates a number of common requirements for pattern matchingand shows what that pattern might look like. These are general examples andmayonlyworkinspecificcases.Table 6-7: Example PatternsREQUIREMENTMatch a non-space token in a string.Match a string beginning with the text MYADDON:followed by at least one character, capturing the rest ofthe string.Match a number, optionally with a fractional part after adecimal point, capturing the entire number. The numbercan be positive or negative.Match an assignment in the form xxxx=yyyy, where xxxxis alphanumeric and yyyy contains no spaces, andcapture each individually.Match a single quoted string, such as 'foo' and 'bar'.Match the last nonspace token in a string.PATTERN“%S+““ ˆ MYADDON:(.+)““(%-?%d+%.?%d*)““(%w+)=(%S+)““%b’’““%S+$“Pattern Matching FunctionsLua provides four functions that accept pattern strings:string.gmatch(s, pattern)string.gsub(s, pattern, repl [, n])string.match(s, pattern [, init])string.find(s, pattern [, init [, plain]])