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 | When this symbol occurs in the argument of a broadcast unit it indicates a "don't care" condition. I.e. any symbol can occur at that particular position of a signal without affecting its acceptance or rejection by the broadcast unit. If the symbol occurs at the last position of an argument it indicates that any terminal string (suffix) may occur from that point onward without affecting acceptance or rejection. |
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For example,  will broadcast 11 if it detects either the signal 1100 or the signal 1000 (or in fact a signal with any of the other symbols at the second position);  will broadcast 11 if it detects any string having the prefix 100, such as 1001 or 10010110 or even 100. |
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 | designates an arbitrary initial or terminal string of symbols (an arbitrary prefix or suffix) when used in the arguments of a given broadcast unit. This symbol gives the unit string-processing capability. |
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For example,  will broadcast the suffix of any signal having the symbols 11 as prefix. Thus if 1100 is detected, the signal 00 will be broadcast, whereas if the signal 11010 is detected, the signal 010 will be broadcast. (The resolution of conflicts, where more than one signal satisfies the input condition, is detailed below.) All occurrences of  within a given broadcast unit designate the same substring, but occurrences in different broadcast units are independent of each other. |
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 | A second symbol used in the same manner as . It makes concatenation of inputs possible (see below). |  | This symbol serves much as and but designates an arbitrary single symbol in the arguments of a given broadcast unit. |
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For example,  broadcasts 10 if 1100 is detected, or 11 if 1110 is detected. |
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| p | When p occurs as the first symbol of a string it designates a string which persists through time (until deleted), even though it is not a broadcast unit. | | This symbol is used to quote symbols in the arguments of a broadcast unit. |
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For example,  broadcasts 10 only if the (unique) string  is detected (i.e., the symbol occurs literally at the third position); without the quote the unit would broadcast 10 whenever any 3 symbol string with the prefix 11 is detected. |
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