JPH02270027A - Storage system for variable - Google Patents

Abstract

PURPOSE:To facilitate the control in a variable storage system by preparing a substituted character storage part and a variable storage part and storing the variable names of the variable storage part in order of addresses. CONSTITUTION:A substituted character storage part 2 stores the contents to be substituted for the variables, and a variable storage part 1 stores a pair of a variable name and the address information showing a specific position of the part 2 that stores the storage contents corresponding to the variable name. Then the variable names of the part 1 are stored in order of addresses. In other words, the constitution of a character string variable is divided into a part where a character variable itself is shown and a part where a substituted character string is stored. Then a pointer showing the latter part is added to the former part and at the same time a variable substitution process is carried out so as to secure an arrangement rule in each area of both parts. Thus an unused memory is easily secured. As a result, the addresses can be easily rewritten in response to the variable names at fluctuation of the number of substituted characters.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a variable storage system for a programmable computer that allows variable-length characters to be assigned to an assignment expression.

<Prior Art> FIG. 3 shows the storage state of a storage device of the prior art. The variable name storage section I stores variable names in alphabetical order, and is previously provided with a substitution character storage section 2 for 16 characters, which is the maximum number of characters that can be substituted. Another conventional technique, as shown in FIG. 4, stores variable names in alphabetical order in a variable name storage section 1, and determines which address in the assignment character storage section 2 the substitution character assigned to this variable name is assigned to. There is a method in which the number of characters that can be stored is stored in the variable name storage unit 1 in correspondence with the variable name. With this method, even if there are few characters to be substituted in the substitution character storage section 2, they can be stored close together, and the number of characters that can be substituted does not need to be particularly limited other than the storage capacity, so the storage capacity of the substitution character storage section 2 can be used effectively. I can do it. When calling this substitution character, first search the variable in the variable storage unit 1, read out the address and number of characters stored corresponding to that variable, and read the data for the character from the address in the substitution character storage unit 2. The assignment character for the variable will be read.

<Problems to be solved by the invention> However, in the conventional example shown in Fig. 3, a substitution character storage unit for 16 characters is always required for one variable, so if there are only 3 characters to be substituted, there are no remaining characters. The memory section for 13 characters becomes wasted. However, if the number of characters in the substitute character storage section 2 is reduced, it will not be possible to cope with the increase in the number of substitute characters, so it is necessary to reserve them for each row.

Furthermore, in the prior art shown in FIG. 4, variable names are stored in the variable name storage section I in a fixed order such as alphabetically, and the substitution character storage section 2 stores the substitution characters in the order in which they are input. If the number of substitution characters stored in storage unit 2 increases, and it is necessary to shift the subsequent substitution characters, the variable name storage unit 2 will not remember the variable name because there is no fixed relationship between the variable name in the variable name storage unit l and the substitution character in the substitution character storage unit 2. Rewriting the address of part l requires extremely complicated control. Note that 3 is an empty area.

Means for Solving Problems> The variable storage method of the present invention includes an assignment character storage section that stores at least contents to be assigned to variables, and a substitution character storage section that stores variable names and storage contents corresponding to the variable names. It is characterized by comprising a variable storage section storing address information indicating in which position in the variable storage section the variables are stored in pairs, and the variable names in the variable storage section are stored in the order of the addresses.

Function: Divide the structure of a string variable into a part that represents the character variable itself and a part that stores the substituted string, add a pointer to the latter part to the former part, and add a pointer to each area of both parts. Unused memory can be easily secured by performing variable assignment processing that gives regularity to the way they are arranged.

<Example> An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing the storage state of variable names and substitution characters according to the present invention. 2 is an assignment character storage unit that stores contents assigned to variables, l is a variable name, and an address indicating in which position of the assignment character storage unit 2 the storage content corresponding to the variable name is stored; This is a variable storage unit that stores the number of characters that can be substituted in pairs. Note that 3 is an empty area and 4 is an unused area.

FIG. 2 is a flowchart showing the operation of the present invention when changing the number of substituted characters.

The flow of variable assignment processing according to the present invention will be explained with reference to FIG. When variable assignment processing occurs, the variable name in the variable storage section I is searched to see if the variable name to be assigned has already been used in Sl. At this time, if the variable name is stored in variable storage section 1, S
If the information is not stored, the process advances to S9.

In S2, the number of characters that can be substituted and the number of characters to be substituted stored corresponding to the searched variable name is compared, and if the number of characters to be substituted is greater, the process proceeds to S3, and if the number of characters to be substituted is less, the process proceeds to S8.

In S3, it is determined whether there is an unused storage area in the substitution character storage unit equal to the number of characters that is the difference between the number of characters that can be substituted and the number of characters to be substituted.
Proceed to.

In S4, subsequent memory character information is shifted by the amount of the difference character to secure a storage area sufficient to store the substitute character.

In S5, the number of characters that can be substituted is compared with the number of characters that have actually been substituted, and it is compared with each character storage information to see if there is a free area 3. If there is even one free area, the process goes to S6.
An error will occur if it does not exist.

In S6, we will refine this area. At this time, in the storage method of the present invention, since the variable names are stored in the order in which the substitution characters are stored, the rewriting process can be performed in the variable name storage section 1 and the substitution character storage section in this order. At this time, the information before the variable name that has already been assigned is packed first, and if there is still not enough storage space, the information after it is packed after.

In S7, it is determined whether the storage area was secured based on the result of S6, and if it was secured, an error occurs in S8 if the storage area could not be secured.

In S8, character information etc. to be substituted into the storage area is newly written, and information such as the address and number of characters is rewritten.

In S9, similarly to S3, it is determined whether there is a storage area that is not stored, and if there is, the process proceeds to SI3, and if there is not, the process proceeds to SIO.

510, Sll, S12, then S5. S6. It performs the same function as S7.

In SI3, the variable name, address, and character count information input this time are added after the variable name, address, and character count information stored at the end of the variable name storage section. Similarly, the currently input substitute character information is stored after the substitute character information stored last in the substitute character storage section.

Effects> As explained above, according to the present invention, the address replacement corresponding to the variable name, which is performed when the number of assigned characters changes, can be performed in the same way, so it can be performed with simple control.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a storage state according to an embodiment of the present invention. FIG. 2 is a flowchart showing the operation of the present invention when changing the number of substituted characters. FIGS. 3 and 4 are diagrams showing storage states of the prior art. t ttShigen Otsu trap, zbxt<>, letter “a”
j',! ta984 agent Patent attorney Takeshi Sugiyama (and 1 other person) Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. In the variable storage method of a programmable computer, there is an assignment character storage section that stores at least the content to be assigned to a variable, and where in the assignment character storage section the variable name and the memory content corresponding to the variable name are stored. and a variable storage unit that stores address information indicating whether the
A variable storage method characterized in that variable names in the variable storage section are stored in the order of the addresses.