Dynamic lexer object construction

Patent metadata

Field	Value
Publication number	US-10365901-B2
Application number	US-201515752021-A
Country	US
Kind code	B2
Filing date	Aug 14, 2015
Priority date	Aug 14, 2015
Publication date	Jul 30, 2019
Grant date	Jul 30, 2019

Abstract

In one example in accordance with the present disclosure, a method for dynamic lexer object construction includes receiving a grammar rule including a variable and a Boolean function to be performed on a character sequence using the variable. The method includes receiving the character sequence and a value corresponding to the character sequence and constructing a lexer object that includes the value as the variable used by the Boolean function. The method includes parsing the character sequence using the lexer object.

First claim

The invention claimed is:

1. A method, comprising:
receiving, as an input, a value for a variable of a grammar rule, the grammar rule defining a structure of a character sequence to be parsed and including a default value for the variable;
replacing the default value in the grammar rule with the received value;
receiving the character sequence;
executing a lexer object that includes a Boolean function that evaluates the character sequence based on the grammar rule; and
parsing the character sequence using the lexer object.

2. The method of claim 1 , wherein the Boolean function includes a matching function and parsing the character sequence further comprises matching the value to a token in the character sequence.

3. The method of claim 1 , wherein the Boolean function is an unmatching function and parsing the character sequence further comprises identifying a token in the character sequence that does not match the variable and determining that the identified token includes a word character.

4. The method of claim 1 , wherein the variable is specified via an application programming interface.

5. The method of claim 1 , wherein the variable represents a standardized value.

6. The method of claim 1 , wherein the function is added to the grammar rule as an extension of a lexer class.

7. A system comprising:
a processor to:
receive an extension of a lexer class defining a Boolean function and a variable used by the Boolean function, wherein the variable represents a value to be found in a character sequence;
replace a default value in a grammar rule with the variable;
receiver to receive the character sequence;
execute a lexer object that includes the Boolean function, wherein the Boolean function evaluates the character sequence based on the grammar rule; and
parse the character sequence using the lexer object.

8. The system of claim 7 , wherein the value is one of: a token, a separator, a character set or a wordchar.

9. The system of claim 7 , wherein the Boolean function includes a matching function and the parser further matches the value to a token in the character sequence.

10. The system of claim 7 , wherein the Boolean function is an unmatching function and the parser further identifies a token in the character sequence that does not match the variable and determines that the identified token includes a word character.

11. The system of claim 7 , wherein the lexer object is to further:
construct the lexer object at run time without re-compiling a grammar rule.

12. A non-transitory machine-readable storage medium comprising instructions that when executed by a processor are to cause the processor to:
receive a grammar rule including a value and a Boolean function to be performed on a character sequence, wherein the Boolean function uses a default value for parsing the character sequence;
receive the character sequence;
construct a lexer object based on the received value; and
parse the character sequence using the lexer object.

13. The non-transitory machine-readable storage medium of claim 12 , wherein the received value represents data to be found in a character sequence.

14. The non-transitory machine-readable storage medium of claim 12 , wherein the received value is specified via an application programming interface.

15. The non-transitory machine-readable storage medium of claim 12 , further comprising instructions that are to cause the processor to:
construct the lexer object in a lexer level.

16. The method of claim 1 , wherein the Boolean function includes a matching function, and wherein parsing the character sequence comprises matching a token of the character sequence with the received value.

17. The method of claim 16 , wherein the value comprises a separator, the method further comprising:
generating a parsed array comprising a plurality of tokens that were separated by the separator in the character sequence.

18. The method of claim 16 , wherein the value comprises a replacement character set, the method further comprising:
replacing a first character set of tokens in the character sequence based on the replacement character set.

19. The method of claim 16 , wherein the value comprises a replacement word, the method further comprising:
replacing a first word in the character sequence based on the replacement word.

20. The method of claim 1 , wherein receiving the value comprises:
retrieving, at runtime, the value from a configuration file that encodes the value.

Assignees

• Entit Software Llc

Inventors

• Chen Qiming
• Hsu Meichun
• Castellanos Malu G

Classifications

• G06F9/54

  Interprogram communication · CPC title

• G06F40/205 Primary

  Parsing · CPC title

• G06F8/425 Primary

  Lexical analysis · CPC title

• G06F8/427

  Parsing · CPC title

• G06F17/2705

  Physics · mapped topic