1. In a text processor comprising input means for inputting a character string comprised of characters of a first type, macro table containing therein as pairs a phrases comprised of characters of a second type and macro codes corresponding to each phrase and comprised of character strings of characters of the first type, and conversion means for effecting a first conversion by searching said macro table based upon the input character string and selecting a phrase from among the phrases contained in the macro table corresponding to the character string inputted by said input means when the input character string is equal to one of the macro codes already contained in said macro table, and for effecting a second conversion by generating a single-character of the second type or a phrase comprised of characters of the second type, both having the same reading as that represented by the input character string when the input character string is not equal to any of the macro codes contained in the macro table; a method for automatically registering frequently used phrases and macro codes therefor into said macro table, comprising steps of: (a) repeatedly storing into a phrase table, phrases each generated by said second conversion for the input character string at least when a generated phrase is different from any of the phrases already stored in said phrase table; (b) incrementing frequency-of-occurrence-data signals of each of the phrases already stored in the phrase table each time a phrase, the same as a phrase already stored in the phrase table, is generated by said second conversion; (c) selecting, at predetermined timings, at least one phrase of the phrases already stored in the phrase table which satisfies a predetermined condition as to frequency of occurrence in order for the phrase to be registered in the macro table, in accordance with the frequency-of-occurrence-data signal of the phrases already stored in the phrase table; (d) determining a macro code for the selected phrase so that the determined macro code differs from any of macro codes already registered in said macro table; (e) registering as a pair the selected phrase and the determined macro code in the macro table; and (f) indicating the selected phrase and the determined macro code to an operator of the text processor.
9. A method for automatically registering frequently used phrases according to claim 1, wherein said phrase selecting step is carried out each time the second conversion is effected.