Terminology of Languages Alphabet:a finite set of symbols (ASCII characters) String Finite sequence of symbols on an alphabet Sentence and word are also used in terms of string -8 is the empty string -s is the length of string s. ● Language:sets of strings over some fixed alphabet -3 the empty set is a language. -(s}the set containing empty string is a language The set of well-formed C programs is a language -The set of all possible identifiers is a language. Operators on Strings: -Concatenation:xy represents the concatenation of strings x and y.s s =s &s=s -sh =sss..s(n times)s CS308 Compiler Theory 6Terminology of Languages • Alphabet : a finite set of symbols (ASCII characters) • String : – Finite sequence of symbols on an alphabet – Sentence and ord are also sed in terms of string Sentence and word are also used in terms of string – ε is the empty string – |s| is the length of string s. • Language: sets of strings over some fixed alphabet – ∅ the empty set is a language. – { ε}h ii i i l } t he set containing empty string is a language – The set of well-formed C programs is a language – The set of all possible identifiers is a language. • Operators on Strings: – Concatenation: xy represents the concatenation of strings x and y. s ε = s ε s = s 6 – s n = s s s .. s ( n times) s 0 = ε CS308 Compiler Theory