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#include <Regex.h>
namespace SCO_SC {
class Substrinfo {
public:
int i;
size_t len;
operator void*();
int operator!();
};
class Subex; // see below
class Regex {
public:
// Enumerations
enum sensitivity { case_sensitive, case_insensitive };
enum { max_num_subexes = 10 };
// Constructor
Regex(const String &pattern,
sensitivity s = case_sensitive);
// Copy and assign
Regex(const Regex & r);
Regex & operator=(const Regex & r);
void assign(const String &pattern,
sensitivity s = case_sensitive);
// Checking pattern validity
operator void*() const;
int operator!() const;
String the_error() const;
// Pattern matching
Substrinfo match(const char *target) const;
Substrinfo match(const char *target,
String &the_substr) const;
Substrinfo match(const char *target, Subex &) const;
Substrinfo match(const char *target, Subex &,
String &the_substr) const;
// Pattern subexpressions
Substrinfo subex(unsigned int i) const;
Substrinfo subex(unsigned int i,
String &the_subex) const;
// Relations
friend int operator==(const Regex &, const Regex &);
friend int operator!=(const Regex &, const Regex &);
// Miscellaneous
String the_pattern() const;
sensitivity the_sensitivity() const;
void set_sensitivity(sensitivity);
// Regex constants
static Regex Int, Float, Double,
Alpha, Alphanum, Identifier;
};
class Subex {
public:
// Constructors, destructor
Subex();
~Subex();
// Subexpression information
Substrinfo operator()(unsigned int i) const;
Substrinfo operator()(unsigned int i,
String &the_substr) const;
// Miscellaneous
const char *the_target() const;
};
class Regexiter {
public:
// Enumerations
enum style { overlapping, nonoverlapping };
// Constructors
Regexiter(const Regex &, const char *target,
style = nonoverlapping);
// Iterating
Substrinfo next();
Substrinfo next(Subex &);
Substrinfo next(String &the_substr);
Substrinfo next(Subex &, String &the_substr);
// Miscellaneous
const char *the_target();
const Regex &the_regex();
style the_style();
};
}
Regex provides the C++ programmer with a consistent and slightly enhanced interface to the Section 3 regular expression compilation and matching routines (see regcmp(3G), regexpr(3G), depending on your machine). Regardless of machine, Regex uses its own regular expression compilation and matching routines, rather than relying on whatever routines may or may not happen to exist in the Section 3 library of your machine.
Regular expressions are as in egrep(1), with the following exceptions: newlines are treated as ordinary characters, $ matches the null character, and \\[0-9] subexpression references are allowed.
The Regex constructor automatically "compiles" the regular expression into an efficient internal form for matching. Member functions can be used to check the validity of the supplied pattern, and if desired, change the pattern.
Regexes can be matched against target strings; as in egrep(1), a match is successful if the pattern is valid and the target contains a matchingsubstring --- that is, a substring (possibly the null string, or the entire string itself) which exactly matches the pattern. Successful matches return the position and length of the leftmost matching substring (in the case of iterators, the leftmost matching substring following the previous matching substring). Successful matches also optionally return a Subex object, which can be used to pick out the substrings of the matching substring which matched the various pattern subexpressions. Finally, the user can pick out the subexpressions of the pattern itself.
In the following, the i'thsubexpression in a regular expression is the subexpression grouped by the i'th left parenthesis, where parentheses are counted from 1 starting at the left of the pattern. For example, in a(b(c))(d), the first, second and third subexpressions are (b(c)), (c), and (d), respectively. The 0'th subexpression is taken to be the entire regular expression.
Locates substrings within a larger string. Functions which return a Substrinfo can be considered to return three values: a boolean, an index, and a length. The boolean is true if the desired substring was found, in which case the index and length are set to the appropriate values. If the caller needs only the boolean, then the return value of the function can be tested directly without first assigning to a Substrinfo.
int i; The starting index of the substring. For example, the starting index of "bar" in "foobar" is 3. Set to -1 if the substring was not found.
size_t len; The length of the substring. Set to 0 if the substring was not found.
operator void*();
int operator!(); Returns non-zero and zero, respectively, if the substring was present.
enum sensitivity { case_sensitive, case_insensitive }; Used to specify whether matching is to be case sensitive or case insensitive. Under case insensitive matching, alphabetic characters are considered to match either their lower or upper case forms; under case sensitive matching, all characters must match exactly.
enum { max_num_subexes = 10 }; Maximum number of parenthesized subexpressions allowed in a pattern. Regexes whose patterns exceed this value are invalid.
Regex(const String &pattern, sensitivity s = case_sensitive); Constructs the regular expression from the given pattern. Notice that backslashes in the pattern must be escaped to get past the C++ compiler. For example, the egrep pattern ^(\+|-)?\.[0-9]+$ must be constructed as Regex("^(\\+|-)?\\.[0-9]+$"), and \\ (the pattern representing a literal backslash) must be constructed as Regex("\\\\"). If s is case_insensitive, then pattern matching (see match) against this Regex will ignore case.
WARNING: When used with character class ranges (e.g., [a-z], [0-9]), case insensitivity is applied only after range expansion. For example, the (rather unusual) range "[A-c]" is always first expanded into the character class { A, B, ..., Y, Z, [, , ], ^, _, `, a, b, c } (using the ASCII collating sequence). Under case sensitive matching this matches any character in the shown set, while under case insensitive matching this matches any character in the set { A, a, B, b, ..., Y, y, Z, z, [, , ], ^, ` }. Similarly, the (rather unusual) range "[a-Z]" is always first expanded into the empty character class (using the ASCII collating sequence). This matches no characters under both case sensitive and case insensitive matching.
Regex(const Regex & r);
Regex & operator=(const Regex & r); Copy constructor and assignment operator.
void assign(const String &pat, sensitivity s = case_sensitive) Equivalent to, but faster than, assigning Regex(pat, s) to this Regex.
operator void*() const;
int operator!() const; Return non-zero and zero, respectively, if the pattern is valid.
String the_error() const; If the pattern is invalid, returns a String describing the reason why, otherwise returns the null String.
Substrinfo match(const char *target) const;
Substrinfo match(const char *target, String &the_substr) const;
Substrinfo match(const char *target, Subex &subex) const;
Substrinfo match(const char *target, Subex &subex, String &the_substr) const; Matches this Regex against the given target. If the match is successful, then assigns the_substr (if supplied) the matching substring, assigns subex (if supplied) an appropriate Subex, and the return value tests true; otherwise the return value tests false and the arguments are not affected.
Substrinfo subex(unsigned int i) const;
Substrinfo subex(unsigned int i, String &the_subex) const; Picks out the i'th subexpression of the pattern. If the pattern has an i'th subexpression, then assigns it to the_subex (if supplied) and the return value tests true; otherwise the return value tests false and the arguments are not affected.
friend int operator==(const Regex & r, const Regex & s);"
friend int operator!=(const Regex & r, const Regex & s);" Equality and inequality. Regexes r and s are considered equal if and only if r.the_pattern() == s.the_pattern() and r.the_sensitivity() == s.the_sensitivity().
String the_pattern() const; Returns the current pattern.
sensitivity the_sensitivity() const;
void set_sensitivity(sensitivity s); Gets and sets, respectively, the case sensitivity of this Regex.
static Regex Int, Float, Double, Alpha, Alphanum, Identifier; The following patterns: ^(\+|-)?[0-9]+$, ^(\+|-)?((\.[0-9]+)|([0-9]+(\.[0-9]*)?))$, ^(\+|-)?((\.[0-9]+)|([0-9]+(\.[0-9]*)?)) ([eE](\+|-)?[0-9]+)?$, ^[A-Za-z]+$, ^[0-9A-Za-z]+$, and ^[A-Za-z_][A-Za-z0-9_]*$.
Subex(); Constructs a Subex, in preparation to being used as a parameter of Regex::match or Regexiter::next.
Substrinfo operator()(unsigned int i) const;
Substrinfo operator()(unsigned int i, String &the_substr) const; Picks out the substring in the_target() which matched the i'th subexpression in the pattern. If the pattern had an i'th subexpression, and the i'th subexpression matched something in the_target(), then assigns the matching substring to the_substr (if supplied) and the return value tests true; otherwise the return value tests false and the arguments are not affected. If this Subex has not been used as an argument of Regex::match or Regexiter::next, then the return value tests false and the arguments are not affected.
const char *the_target() const; Returns the target which was matched against by the most recent call to Regex::match() or Regexiter::next() to which this Subex was supplied as an argument. If there is no such call, returns 0.
Iterating a Regex over a given target picks out, in sequence, all the matching substrings in the target, beginning with the leftmost and continuing to the right.
enum style { overlapping, nonoverlapping }; Used to specify whether iteration is to be overlapping or nonoverlapping. Under overlapping iteration, the matching substring of second and later iterations is allowed to overlap a proper suffix of the matching substring of the previous iteration. Under nonoverlapping iteration, all matching substrings are disjoint.
Regexiter(const Regex &r, const char *target, style s = nonoverlapping); Constructs an iterator for r over the given target. The iterator internally stores a reference to r, and hence it is a program error to delete or move r while this iterator is extant.
Substrinfo next();
Substrinfo next(Subex &subex);
Substrinfo next(String &the_substr);
Substrinfo next(Subex &subex, String &the_substr); Picks out the next matching substring in the target. Arguments and return value are as in Regex::match().
const char *the_target(); Returns the value of target which was supplied to this Regexiter's constructor.
const Regex &the_regex(); Returns a constant reference to the Regex which was supplied to this Regexiter's constructor.
style the_style(); Returns the style.
There ought to be conversions between Regex's and Fsm's (see Fsm(3C++)).