Mikroelektronika MIKROE-742 데이터 시트

Regular Expressions are a widely-used method of specifying patterns of text to
search for. Special metacharacters allow you to specify, for instance, that a particu-
lar string you are looking for, occurs at the beginning, or end of a line, or contains 

n

recurrences of a certain character. 

Any single character matches itself, unless it is a metacharacter with a special
meaning described below. A series of characters matches that series of characters
in the target string, so the pattern 

would match 

in the target string.

You can cause characters that normally function as metacharacters or escape
sequences to be interpreted by preceding them with a backslash 

. 

For instance, metacharacter

matches beginning of string, but 

matches

character 

, and 

matches 

, etc. 

matches string

'

unsigned' 

\^

matches string

'^

unsigned' 

Characters may be specified using a escape sequences: 

"

\n"

matches a newline,

"\t"

a tab, etc. More generally, 

, where 

is a string of hexadecimal digits,

matches the character whose ASCII value is

. 

If you need wide (Unicode) character code, you can use 

'

\x{nnnn}'

, where 

'

nnnn'

- one or more hexadecimal digits.

- char with hex code 

- char with hex code 

(one byte for plain text and two bytes for Unicode) 

- tab (HT/TAB), same as 

- newline (NL), same as 

- car.return (CR), same as 

- form feed (FF), same as 

- alarm (bell) (BEL), same as

- escape (ESC) , same as 

matches 

'

unsigned int'

(note space in the middle)

matches

'

unsigned'

(predecessed by tab) 

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- SOFTWARE AND HARDWARE SOLUTIONS FOR EMBEDDED WORLD

CHAPTER 2