arbitrary text will be terminated by the occurrence of any terminal in the language defined in the lex specification whose value is above 128 thus the following snippet of bnf will cause the field u2018 pubname u2019 to be assigned whatever text occurs between the token lt publication gt and lt volume issue gt in the input file in the preferred embodiment when extracting these arbitrary text fields all trailing and leading white space is removed from the string before assignment and all occurrences of line_feed are removed to yield a valid text string the fact that tokens below 128 will not terminate the arbitrary text sequence is important in certain situations where a particular string is a terminal in the language and yet might also occur within such a text sequence where it should not be considered to have any special significance all such tokens can be assigned token numbers below 128 in the lex specification thus ensuring that no confusion arises the occurrence of another lt 1 1 gt or a lt 1 4 gt plug in causes any previous lt 1 string gt text accumulated to be discarded a lt 1 5 gt causes execution of a c statements that generally cause extracted information to be assigned to the specified field and then clears the record of the accumulation if a plug in hint consisting of a decimal number follows the lt 1 1 gt as in lt 1 1 4 gt that number specifies the maximum number of lines of input that will be consumed by the plug in four in this example this is a useful means to handle.