remigermain / regex

Regular expression WIP

Prototype

ft_regex_exec

Compare s1 to reg's pattern

int	ft_regex_exec(t_regex *st, const char *s1, const char *reg)

• return 0 if si not match
• return positive integer for number that match
• return -1 for error allocation memory
• t_regex the struct with all information
• s1 is your string
• reg is your regex pattern

ft_regex_replace

Compare s1 to reg's pattern and replace all capturing string with rep's string

char	*ft_regex_replace(const char *s1, const char *reg, char *pat, enum e_regex_replace mod)

• return NULL ptr if error in allocation memory
• s1 is your string
• reg is your regex pattern
• pat is for replace string
• enum is for mod

mod	Description
REG_FIRST	Replace first pattern matching
REG_LAST	Replace last pattern matching
REG_ALL	Replace all pattern matching

ft_regex_print

For printings results

void    ft_regex_print(t_regex *st)

• print t_regex struct

ft_regex_free

You need to be free the structure after matching

void	ft_regex_free(t_regex *st)

• free t_regex struct

REGEX

Class

exemple	Description
[]	nothings
[0]	The character "0"
[0-9]	Any number
[[:isdigit:]]	Any number
[\d]	Any number
[^0-9]	Any character other than a number
[^[:isdigit:]]	Any character other than a number
[^\d]	Any character other than a number
[-0-9]	Any number or a "-"
[0-9-]	Any number or a "-"
[^-0-9]	Any character except a number or a "-"
[]0-9]	Any number or a "]"
[0-9]]	Any number followed by a "]"
[0-9-z]	Any number, or any a "-", or "z".
[0-9\-a\]]	Any number, or a "-", a "a", or a "]"

Character class

POSIX	Non standard	perl	Description
	[:word:]	\w	Alphanumeric characters plus "_"
		\W	Non-word characters
	[:ascii:]		ASCII characters
[:alnum:]			Alphanumeric characters
[:alpha:]			Alphabetic characters
[:blank:]			Space and tab
[:cntrl:]			Control characters
[:digit:]		\d	Control characters
		\D	Non-digits
[:graph:]			Visible characters
[:lower:]			Lowercase letters
[:print:]			Visible characters and the space character
[:punct:]			Punctuation characters
[:space:]		\s	Whitespace characters
		\S	Non-whitespace characters
[:upper:]			Uppercase letters
[:xdigit:]			Uppercase letters

Quantifier

By default , quantifier as Greedy means match longest possible string . The lazy mode of quantifiers is an opposite to the greedy mode. It means: “repeat minimal number of times”. If you need lazy quantifier , add ? at the end of quantifier

quantifier	lazy	Description
?	??	Matches the preceding element zero or one time. For example, ab?c matches only "ac" or "abc".
+	+?	Matches the preceding element one or more times. For example, ab+c matches "abc", "abbc", "abbbc", and so on, but not "ac".
*	*?	Matches the preceding element zero or more times. For example, ab*c matches "abc", "abbc", "ac"
{m,n}	{m,n}?	Matches the preceding element at least m and not more than n times. For example, a{3,5} matches only "aaa", "aaaa", and "aaaaa". This is not found in a few older instances of regexes. BRE mode requires {m,n}.
{,n}	{,n}?	Matches the preceding element zero or n time
{m,}	{m,}?	Matches the preceding element at least m time or more
{m;n}	{m;n}?	Matches the preceding element m time or n time
{m}	-	Matches the preceding element m time

Sepcial

metachar	Description
^	Matches the starting position within the string. In line-based tools, it matches the starting position of any line.
|	The choice (also known as alternation or set union) operator matches either the expression before or the expression after the operator. For example, abc|def matches "abc" or "def".
.	Matches any single character (many applications exclude newlines, and exactly which characters are considered newlines is flavor-, character-encoding-, and platform-specific, but it is safe to assume that the line feed character is included). Within POSIX bracket expressions, the dot character matches a literal dot. For example, a.c matches "abc", etc., but [a.c] matches only "a", ".", or "c".
$	Matches the ending position of the string or the position just before a string-ending newline. In line-based tools, it matches the ending position of any line.
\n	newline
\t	tab
\r	return
\e	escape
\0x44	hex ascii code
\0777	octal ascii code

Enclose

metachar	Description
( )	Defines a marked subexpression. The string matched within the parentheses can be recalled later (see the next entry, \n). A marked subexpression is also called a block or capturing group. BRE mode requires ( ).