Developing Apama Applications > EPL Reference > Lexical Elements > Symbols
Symbols
Symbols (also called tokens, atoms, or lexemes) are the elements and words of the language, consisting of identifiers, keywords, operators, separators, and literals. Symbols are composed of one or more characters, excluding white space, comments, and line terminators.
Sometimes you must use at least one white space character between two symbols in order to make them distinguishable from each other and from another symbol. For example, the symbol >> is the right-shift operator and the symbol > is used to indicate the end of the element type in a sequence declaration. Since you can have a sequence of sequences, such a declaration could have two adjacent symbols. Since >> in a sequence declaration looks just like the right-shift operator, you have to write them with a white space character between them: > >. On the other hand, the expression a-b (subtract the value of the variable named b from the value of the variable named a) is unambiguous and no extra white space characters are needed. If you wrote it as a - b it would mean the same thing.
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