1. Field of the Invention
This invention relates to word processors and more particularly to a word processor having a function of creating documents including a character-symbol train having a special position and size such as a formula.
2. Related Background Art
Conventionally, to create a document including a formula such as is shown in FIG. 8, the input of the formula portions 81, 82, 83 are processed separately from that of the ordinary text by defining a floating block or a fixed block to perform therein the input and creation of the formula by combining a plurality of lines of character trains using, where necessary, a command such as modification of the line pitch.
However, the above method, in which the input areas are separately defined for text and formulas, is disadvantageous in that not only is an additional step required for the operation of defining a block for the input of a formula, but also the operation of re-defining the block size when the size of the formula must be increased during the input/editing operation is required.
Further, if a formula is created by combining ordinary characters without defining a separate input area therefor, the formula cannot be processed as a block, and thus input/editing operation of any portion other than the formula will cause only the formula portion to move, whereby a problem of not only destroying the created formula but also not allowing complicated formulas to be created exists.
Furthermore, there is another method involving the steps of suspending a document editing process being currently performed, creating a formula portion separately from the document, and combining the created formula portion with the document. However, this method also requires cumbersome formula input operations; in order to perform editing such as correcting the formula portion with this method, it is necessary to repeat the above steps of creating a formula and combining it with the document.
Now, apart from the relation between the document and the formula, let us refer to the input of symbols such as formulas. One conventional method requires the input of commands, for example, "SQUARE ROOT [X+Y]" or "A SUFFIX i" to input a formula with a square root or a character with a subscript, which means that it is necessary to input additional characters and symbols which are completely different from what is desired as a final product: "X +Y" and "Ai"
Further, although in the ordinary method of adding, for example, a square root symbol, the form, size, and position of the square root are defined in accordance with the size of an object to which the square root is to be added, some conventional word processors follow a simple expression which is different from that ordinary method. In defining the form of the square root in accordance with the character train to which the square root is to be added, the operator has to make his or her decision with reference to the displayed or printed results. This method requires repetition of the same input operation until one suitable form, size or the like of the symbol is selected and defined, and as a result, it entails not only much time but also hard work on the part of the operator even burdening him or her with a risk of making errors.
In the case where the length of the character train to which the square root symbol is to be added must be modified due to an editing operation such as correction, and the position and form of the square root have to be revised, the above method requires that a completely new round of input operations be executed; it is not possible to make a partial correction such as to only input a new square root symbol to the already input character train.
Further, a formula such as a fraction, in which a term taking up a plurality of lines and a term taking up only a single line are included, imposes a problem of producing a bottom-aligned, ill-balanced display when expressed with reference to a single base line. A numerator displayed in left- or right-aligned form does not look good, either. Thus, in order to express the fraction in a well-balanced, good-looking manner, it is necessary to define the position in accordance with the size and form of its constituents. As is the case with the input of the square root, the operator has to follow the steps of defining and editing the position with reference to the output results, and if the output does not look good, he has to repeat a series of steps all over again.
Furthermore, as to paired symbols which are to be arranged mutually spaced apart such as a pair of parentheses, each is input separately; thus the problem exists in that, in the case of a pair of parentheses, the closing parenthesis is often missing.