JPH06214798A - Programing language compiler - Google Patents

Abstract

PURPOSE:To increase the free degree of programming so as to facilitate program generation and make a program easy to read by calling the same partial program by means of plural different names. CONSTITUTION:At first, a present symbol table is read in a function name retrieval procedure generating part 11 and function name retrieval procedure (procedure for inspecting the matching of normal expression with a character string) is prepared. Then, in a function name retrieval precedure executing part 12, it is inspected whether or not a function name delivered from a syntax element decomposing part 8 in accordance with function name retrieval procedure matches with the function name (the character string of formal expression) in the symbol table. Information belonging to the function name is delivered to a function calling-out code output part 13. Thus, the function name can be called out by the plural different function names matching with it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a programming language compiler. More specifically, when defining a partial program such as a function or subroutine, the name of the partial program is allowed to be written according to a predetermined character string notation rule, and a plurality of names matching the defined name are allowed. It relates to a compiler that can call the partial program with different names.

[0002]

2. Description of the Related Art As a program for controlling the operation of a CPU of a computer, first write a program (source program) in a programming language that is easy for humans to understand.
It is created by translating this into a machine language or intermediate code with a compiler for that language. Many of these programming languages create a part of a program that is repeatedly used or a part that performs a specific process as a part program of a predetermined format called a function or subroutine, and name it The programming technique that can be used by calling the partial program by (identifier) is adopted.

In such a programming language, the name described in the call of the partial program and the name at the time of defining the partial program must be perfectly matched as a character string. Therefore, it was not possible to call the same partial program with a different name (for example, a name in which some of the letters in the name are large or small).

[0004]

An object of the present invention is to increase the degree of freedom in programming by making it possible to call the same partial program with a plurality of different names, thereby facilitating the creation of a program and also It aims to provide a programming language compiler that makes it easier to read.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, a first invention of the present application is a compiler of a programming language, wherein when defining a partial program such as a function or subroutine, the name of the partial program is represented by a predetermined character string table. It is characterized by adding a function that allows notation according to the notation and that the partial program can be called by a plurality of different names that match the defined name. A second invention of the present application is the compiler for the above programming language, wherein the character string notation rule is a regular expression.

A third invention of the present application is a compiler of the above programming language, wherein the name of a partial program described according to the character string notation rule is registered in a symbol table, and any character string is the character string notation rule. According to the procedure described above, a procedure for checking whether or not the name is matched is created, and when the function call code is translated, the function to be called is searched according to the procedure. A fourth invention of the present application is a compiler of a programming language, which allows a name of a partial program to be expressed according to a predetermined character string notation rule when defining a partial program such as a function or subroutine, and The feature is that the function to call the partial program by a plurality of different names that match the defined name is realized as a preprocessor of an existing programming language compiler.

[0007]

The present invention will be described in detail below with reference to the illustrated embodiments. FIG. 1 is an explanatory diagram showing the configuration and operation of the compiler according to the first embodiment of the present invention. The compiler of this embodiment allows a function name to be expressed in a regular expression when defining a function, and allows the function to be called by a plurality of different names that match the defined name. Is.

The most basic components of regular expressions are:・ Normal character (alphabet, number, symbol): Match the same character. -A character string enclosed in square brackets ([]): Matches all the characters inside the square brackets. For example, [abc] matches a, b or c.・ Period (.): Matches any one character. -Asterisk (*): Matches the preceding character (regular expression notation is possible) zero or more times. For example, ab * matches a, ab, abb, ....

Further, various notation rules can be added to enhance the notation ability of regular expressions. The typical ones are: -Haiphong (-): Specify the range of characters. For example [a
-z] matches the letters a through z.・ Caret (^): Specifies characters that do not match. For example, [^ abc] matches any character except a, b, or c. -Plus (+): Matches the preceding character (regular expression notation is possible) one or more times. For example ab +
Matches ab, abb, abbb, .... And so on.

In the configuration of FIG. 1, as in the conventional compiler, the lexical analyzer 1 first defines the source program according to the grammatical rules such as identifiers (names of variables and functions), instructions, operators, numerical values, etc. It divides into the smallest unit that has, that is, a token. Next, the syntactic analysis unit 2 analyzes the types and arrangements of these lexical characters according to the grammatical rules, and checks which of the syntaxes such as the function definition and the function invocation these lexical strings correspond to. The lexical set corresponding to the syntax element of the syntax is passed to the code generation unit of the corresponding syntax. The code generation part of each syntax (only the code generation part 3 of the function call and the generation part 4 of the code of the function definition are shown in FIG. 1) is passed from the syntax analysis part 2. Convert characters to machine code.

It is assumed that a function is now defined in the program, with line (1) in FIG. 2 being the first line. In the definition of this function, [A-Za-z] + is the name of the function expressed by a regular expression and means "a string of one or more uppercase or lowercase letters". Also, (X, Y) indicates the argument of the function. Then, this compiler first converts this code into a lexical string in the lexical analysis unit 1, and then checks in the syntactic analysis unit 2 what syntax the lexical string forms, and determines that it is a lexical string of a function definition. , The lexical string is
To the generating unit 4.

The function code generation unit 4 decomposes the lexical sequence from the syntax analysis unit 2 into individual lexical units in its syntax element decomposition unit 5, and the lexical characters corresponding to the function names therein are registered in the function name registration unit 6. hand over. The function name registration unit 6 registers the passed function name in the symbol table 7. This symbol table is a table that stores a character string of an identifier (symbol), its type (for example, whether it is a function name or a variable name), and attached information (location in the program, etc.). Is. FIG. 3 shows a state in which the function name of FIG. 2 is stored in the symbol table. In this embodiment, the regular expression is stored as it is. The storage order of each symbol in the symbol table can be associated with the appearance order of the identifiers in the program.

As the processing of the compiler further progresses, as shown in FIG.
Suppose there is a function call as shown in the line (2). Then, the compiler performs the lexical analysis unit 1 as described above.
At this time, this code is converted into a lexical string, the syntax analyzing unit 2 checks which syntax the lexical string forms, and passes the lexical string to the function call code generating unit 3. This lexical string includes the character string Az that constitutes the function name.

In the prior art, as shown in FIG. 5, after the syntax element decomposition unit 8 of the function call code generation unit 3 decomposes this lexical string into syntax elements, the function name is passed to the function retrieval unit 9. The function name search unit 9 checks whether there is the same function name (that is, the type is the function name and the identifier has the same character string structure), and if there is, the information attached to the function name is output to the function call code output unit. I was delivering to 10.

On the other hand, in the present embodiment, first, the function name search procedure generating unit 11 reads the current symbol table and creates a function name search procedure (a procedure for checking the matching between the regular expression and the character string). In the function name search procedure execution unit 12, it is checked according to the function name search procedure whether or not the function name passed from the syntax element decomposition unit 8 matches the function name (character string or regular expression) in the symbol table. If there is a match, the information attached to the function name is passed to the function call code output unit 13.

Function name [A-Za-z] + in the function definition of FIG.
The function name search procedure for is shown in the state transition diagram of FIG. In FIG. 4, S represents the start state, that is, the start of the matching test, is a state in which the function name has been matched until then, is a state in which the character string does not match from this function name, is Shows the state that matches the function name. The function name Az in the function call in Fig. 2 changes from state S to state because the first character is A, and from state to state again because the second character is z. Transition to
Match the function name [A-Za-z] +. Thus the function name [AZ
az] + can be called with several different function names that match it.

In this embodiment, the regular expression is used as the character string notation rule that can express the function name when the function is defined, but any other character string notation rule can also be used. Further, the present embodiment is a programming language compiler in which a partial program is created in a format called a function, but it can be similarly implemented in a programming language compiler created as a partial program in another format. Furthermore, in this embodiment, when defining a partial program such as a function or subroutine, it is allowed to describe the name of the partial program according to a predetermined character string notation rule, and a plurality of names matching the defined name are allowed. Although the function to call the partial program with a different name is built into the compiler, this function can also be realized as a preprocessor of a compiler of an existing programming language.

[0018]

As described above, according to the present invention, when a partial program such as a function or subroutine is defined in a compiler of a programming language, the name of the partial program is expressed according to a predetermined character string notation rule. Tolerate,
In addition, since it has the function of calling the partial program with a plurality of different names that match the defined name, (1) the same partial program can be called with a plurality of different names (for example, Names with different sizes of letters in parts). (2) In object-oriented programming, declare in advance that "other methods do nothing". It becomes possible to do things, etc., and has a great effect on increasing the degree of freedom in programming. As a result, the program can be easily created and the program can be easily read.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing the configuration and operation of a compiler according to an embodiment of the present invention.

FIG. 2 shows a function definition in which a function name is expressed by a regular expression and a program example of calling the function.

FIG. 3 is an explanatory diagram of registration of a function name represented by a regular expression in a symbol table.

FIG. 4 is an explanatory diagram showing a function name search procedure in a state transition diagram.

FIG. 5 is an explanatory diagram showing the configuration and operation of a conventional compiler.

Claims (4)

[Claims] 1. A compiler of a programming language, which allows a name of a partial program to be expressed according to a predetermined character string notation rule when defining a partial program such as a function or subroutine, and is defined. A programming language compiler characterized by adding a function to call the partial program by a plurality of different names matching the specified name. 2. The compiler according to claim 1, wherein the character string notation rule is a regular expression. 3. The compiler of the programming language according to claim 1, wherein the name of the partial program described according to the character string notation rule is registered in a symbol table, and an arbitrary character string is described according to the character string notation rule. A compiler of a programming language, characterized in that a procedure for checking whether or not it matches a specified name is created, and a function to be called is searched according to the procedure when the function call code is translated. 4. A compiler of a programming language, which allows a name of a partial program to be expressed according to a predetermined character string notation rule when defining a partial program such as a function or subroutine, and is defined. A compiler of a programming language, which realizes a function of calling a partial program by a plurality of different names that match the name of the same as a preprocessor of a compiler of an existing programming language.