Class RegExpSupport

Constants, some built from others by static methods, to expedite common tasks that use regular expressions.

Inheritance

System.Object

RegExpSupport

Inherited Members

System.Object.ToString()

System.Object.Equals(System.Object)

System.Object.Equals(System.Object, System.Object)

System.Object.ReferenceEquals(System.Object, System.Object)

System.Object.GetHashCode()

System.Object.GetType()

System.Object.MemberwiseClone()

Namespace: WizardWrx

Assembly: WizardWrx.Common.dll

Syntax

public static class RegExpSupport

Remarks

Reference: RegExLib.com Regular Expression Cheat Sheet (.NET), at the cross reference cited below.

Fields

CARRIAGE_RETURN

Represents a Carriage Return (CR in Windows text) in a Regular Expression

Declaration

public const string CARRIAGE_RETURN = "\\r"

Field Value

Type	Description
System.String

ESCAPED_QUOTE

Escaped quote, used to embed quotation marks in regular expressions.

Declaration

public const string ESCAPED_QUOTE = "\\\""

Field Value

Type	Description
System.String

FRIEDL_GRAY_WHOLE_HTML_TAG_MATCH

Use this to get the whole XML body in one long string. Repeated uses should allow you to perform stepwise refinements, until you get to the innermost tag.

Declaration

public const string FRIEDL_GRAY_WHOLE_HTML_TAG_MATCH = "<(/?\\w+)((\\s+\\w+(\\s*=\\s*(?:\".*?\"|'.*?'|[^'\">\\s]+))?)+\\s*|\\s*)/?>.+?</\\1>"

Field Value

Type	Description
System.String

FRIEDL_HTML_TAG_MATCH

Jeffrey Friedl's regular expression for matching any arbitrary HTML tag.

Jeffrey Friedl is the author of Mastering Regular Expressions, published by O'Reily, which is regarded as the "Bible" of Regular Expressions.

Declaration

public const string FRIEDL_HTML_TAG_MATCH = "</?\\w+((\\s+\\w+(\\s*=\\s*(?:\".*?\"|'.*?'|[^'\">\\s]+))?)+\\s*|\\s*)/?>"

Field Value

Type	Description
System.String

MATCH_ALTERNATION

Like the binary Logical OR operator in a logical expression, this character says "match either the character on its left OR the character on its right.

Regular expressions may contain many alternations, forming a group that behaves commutatively.

Declaration

public const char MATCH_ALTERNATION = '|'

Field Value

Type	Description
System.Char

MATCH_ESCAPE

Preceding another meta-character, one of these tells the Engine to treat the meta character as a literal.

Preceding certain other characters, one of these signals a special, non-printing character. For example, preceding a lower case a, it signifies an Alarm (Bell). More commonly, however, before a lower case t, this character signifies a Tab, before a lower case n means a Newline, and a lower case r denotes a Carriage Return.

N. B. A Newline in the .NET RegExp Engine and in the Perl RegExp Engine are two different things.

Declaration

public const char MATCH_ESCAPE = '\\'

Field Value

Type	Description
System.Char

MATCH_GROUP_BEGIN

Define the start of a group. This is the same as a subexpression in Perl.

Declaration

public const char MATCH_GROUP_BEGIN = '('

Field Value

Type	Description
System.Char

MATCH_GROUP_END

Define the end of a group. This is the same as a subexpression in Perl.

Declaration

public const char MATCH_GROUP_END = ')'

Field Value

Type	Description
System.Char

MATCH_MULTIPLE_PREVIOUS_CHAR

Match zero or more of the previous character or expression.

Declaration

public const char MATCH_MULTIPLE_PREVIOUS_CHAR = '*'

Field Value

Type	Description
System.Char

MATCH_ONE_OR_MORE_PREVIOUS_CHAR

Match one or more of of the previous character or expression.

Declaration

public const char MATCH_ONE_OR_MORE_PREVIOUS_CHAR = '+'

Field Value

Type	Description
System.Char

MATCH_SHORTEST

Append to a greedy match to make it match the fewest possible characters.

Declaration

public const char MATCH_SHORTEST = '?'

Field Value

Type	Description
System.Char

MATCH_STRING_END

Match end of line, absent the String modifier, which changes its meaning to match end of the entire String.

Declaration

public const char MATCH_STRING_END = '$'

Field Value

Type	Description
System.Char

MATCH_STRING_START

Match start of line, absent the String modifier, which changes its meaning to match start of the entire String.

Declaration

public const char MATCH_STRING_START = '^'

Field Value

Type	Description
System.Char

MATCH_WILDCARD_CHAR

Match one of any character, except a Newline (absent the String modifier, which adds the Newline to the list of matched characters.

Use MATCH_MULTIPLE_PREVIOUS_CHAR to extend the match to a string of the same character.

Use MATCH_SHORTEST, following this character, followed by MATCH_MULTIPLE_PREVIOUS_CHAR, to limit the match.

Declaration

public const char MATCH_WILDCARD_CHAR = '.'

Field Value

Type	Description
System.Char

MODIFIED_FRIEDL_HTML_TAG_MATCH

This is a derivation of Jeffrey Friedl's regular expression, adapted to capture the tag name in the first submatch.

Declaration

public const string MODIFIED_FRIEDL_HTML_TAG_MATCH = "<(/?\\w+)((\\s+\\w+(\\s*=\\s*(?:\".*?\"|'.*?'|[^'\">\\s]+))?)+\\s*|\\s*)/?>"

Field Value

Type	Description
System.String

NEWLINE

Represents a Newline (CR/LF in Windows text) in a Regular Expression

Declaration

public const string NEWLINE = "\\r\\n"

Field Value

Type	Description
System.String

Remarks

See "How to avoid VBScript regular expression gotchas," at http://www.xaprb.com/blog/2005/11/04/vbscript-regular-expression-gotchas/, especially the responses.

PAGE_TAG_PREFIX

Match the beginning of the Page tag in a ASP.NET page.

Declaration

public const string PAGE_TAG_PREFIX = "<%@ Page"

Field Value

Type	Description
System.String

PAGE_TAG_SUFFIX

Match the end of the Page tag in a ASP.NET page.

Declaration

public const string PAGE_TAG_SUFFIX = "%>"

Field Value

Type	Description
System.String

REGEXP_FIRST_MATCH

Not surprisingly, the .NET regular expression returns a collection of matches. Like all collections, individual members are numbered from zero.

Declaration

public const int REGEXP_FIRST_MATCH = 0

Field Value

Type	Description
System.Int32

REGEXP_FIRST_SUBMATCH

In the .NET version of the regular expression matching engine, the subexpressions are numbered from 1, just as they are in Perl.

Declaration

public const int REGEXP_FIRST_SUBMATCH = 1

Field Value

Type	Description
System.Int32

REGEXP_WHOLE_MATCH

In the .NET version of the regular expression matching engine, the first group, whose index is zero, matches the whole expression.

Declaration

public const int REGEXP_WHOLE_MATCH = 0

Field Value

Type	Description
System.Int32

SGML_CLOSING_TAG_ANY

Match any closing HTML or XML tag.

Except in special cases, you should employ the IgnoreCase modifier.

Declaration

public const string SGML_CLOSING_TAG_ANY = "</(.*?)>"

Field Value

Type	Description
System.String

SGML_CLOSING_TAG_ARBITRARY

Match an arbitrary closing HTML or XML tag.

Except in special cases, you should employ the IgnoreCase modifier.

You must interpolate the tag name into this string by calling the the static string.Format method, passing this string as the format and the tag as the sole substitution value.

You may also pass a tag name to method MatchArbitraryHtmlClosingTag, which returns a pattern. For example, to find all Anchor tags, pass "A" to MatchArbitraryHtmlClosingTag.

Declaration

public const string SGML_CLOSING_TAG_ARBITRARY = "</({0})>"

Field Value

Type	Description
System.String

SGML_COMPLETE_BODY

Match the whole body of any HTML document. Except in special cases, you must employ the String and IgnoreCase modifiers to get this expression to work.

Declaration

public const string SGML_COMPLETE_BODY = "<body .*?>(.*?)</body>"

Field Value

Type	Description
System.String

SGML_COMPLETE_HEAD

Match the entire Head section of any HTML document. Except in special cases, you must employ the String and IgnoreCase modifiers to get this expression to work.

Declaration

public const string SGML_COMPLETE_HEAD = "<head.*?>(.*?)</head>"

Field Value

Type	Description
System.String

SGML_COMPLETE_HTML_DOC

Match the entirety of any HTML document. Use this expression to discard preceding HTTP headers. Except in special cases, you must employ the String and IgnoreCase modifiers to get this expression to work.

Declaration

public const string SGML_COMPLETE_HTML_DOC = "<html>(.*?)</html>"

Field Value

Type	Description
System.String

SGML_COMPLETE_TAG_ARBITRARY

Match an arbitrary HTML or XML tag that appears on a single line (or multiple lines, if the String modifier is employed).

Except in special cases, you should employ the IgnoreCase modifier.

You must interpolate the tag name into this string by calling the the static string.Format method, passing this string as the format and the tag as the sole substitution value.

You may also pass a tag name to static method MatchArbitraryHtmlTag, which returns a pattern. For example, to find all Anchor tags, pass "A" to MatchArbitraryHtmlTag.

Declaration

public const string SGML_COMPLETE_TAG_ARBITRARY = "<({0})(.*?)>(.*?)</{0}>"

Field Value

Type	Description
System.String

SGML_OPENING_TAG_ANY

Match any opening HTML or XML tag.

Except in special cases, you should employ the IgnoreCase modifier.

Declaration

public const string SGML_OPENING_TAG_ANY = "<(.*?)(.*?)>"

Field Value

Type	Description
System.String

SGML_OPENING_TAG_ARBITRARY

Match an arbitrary opening HTML or XML tag.

Except in special cases, you should employ the IgnoreCase modifier.

You must interpolate the tag name into this string by calling the the static string.Format method, passing this string as the format and the tag as the sole substitution value.

You may also pass a tag name to method MatchArbitraryHtmlOpeningTag, which returns a pattern. For example, to find all Anchor tags, pass "A" to MatchArbitraryHtmlOpeningTag.

Declaration

public const string SGML_OPENING_TAG_ARBITRARY = "<({0})(.*?)>"

Field Value

Type	Description
System.String

TITLE_ATTRIBUTE_LABEL

Title attribute of the ASP.NET Page tag looks like this.

Declaration

public const string TITLE_ATTRIBUTE_LABEL = "Title="

Field Value

Type	Description
System.String

Methods

ExtractTextBetweenMatches(MatchCollection, Int32, String)

Given the System.Text.RegularExpression.Match at index pintMatchIndex in System.Text.RegularExpression.MatchCollection prxpMatchCollection, return the substring that follows the matching text in string pstrInputString up to the beginning of the next match, or the rest of the string inthe case of the last match.

Declaration

public static string ExtractTextBetweenMatches(MatchCollection prxpMatchCollection, int pintMatchIndex, string pstrInputString)

Parameters

Type	Name	Description
System.Text.RegularExpressions.MatchCollection	prxpMatchCollection	Pass in a reference to the System.Text.RegularExpression.MatchCollection attached to a System.Text.RegularExpression.Regex that has one or more matches.
System.Int32	pintMatchIndex	Pass in an integer that represents the index of the Match in prxpMatchCollection for which to return the text that follows the text that matched it. This integer must be greater than or equal to zero and less than the Count property on MatchCollection prxpMatchCollection.
System.String	pstrInputString	Pass in a reference to the string that was fed into the prxpMatchCollection constructor. This value cnnot be NULL or the empty string. It is the caller's responsiblity to pass in the same string that was passed into the constructor that created the prxpMatchCollection because this function makes no efrort to use Reflection to test it.

Returns

Type	Description
System.String	There are two possible return values:

Remarks

This method was perfected independently in my RegExpLab project.

MatchAnyCharacterGreedy()

Return a string that matches the maximum number of any character.

Declaration

public static string MatchAnyCharacterGreedy()

Returns

Type	Description
System.String

MatchAnyCharacterLeastGreedy()

Return a string that matches the minimum number of any character.

Declaration

public static string MatchAnyCharacterLeastGreedy()

Returns

Type	Description
System.String

MatchArbitraryHtmlClosingTag(String)

Interpolate a tag name into the SGML_CLOSING_TAG_ARBITRARY match expression template.

Declaration

public static string MatchArbitraryHtmlClosingTag(string pstrTagName)

Parameters

Type	Name	Description
System.String	pstrTagName	String containing the name of the tag to match.

Returns

Type	Description
System.String	A Regular Expression match expression that will match the closing tag named in argument pstrTagName.

MatchArbitraryHtmlOpeningTag(String)

Interpolate a tag name into the SGML_OPENING_TAG_ARBITRARY match expression template.

Declaration

public static string MatchArbitraryHtmlOpeningTag(string pstrTagName)

Parameters

Type	Name	Description
System.String	pstrTagName	String containing the name of the tag to match.

Returns

Type	Description
System.String	A Regular Expression match expression that will match the opening tag named in argument pstrTagName.

MatchArbitraryHtmlTag(String)

Interpolate a tag name into the SGML_COMPLETE_TAG_ARBITRARY match expression template.

Declaration

public static string MatchArbitraryHtmlTag(string pstrTagName)

Parameters

Type	Name	Description
System.String	pstrTagName	String containing the name of the tag to match.

Returns

Type	Description
System.String	A Regular Expression match expression that will match the tag named in argument pstrTagName.

MatchAspNetPageTag()

Return a string that matches the Page tag in a ASP.NET document.

Declaration

public static string MatchAspNetPageTag()

Returns

Type	Description
System.String

MatchFileName(String, String)

Match file names against a true regular expression, as opposed to the anemic masks supported by DOS and Windows. Though occasionally referred to as regular expressions, file specifications that use DOS wild cards are a far cry from true regular expressions.

Declaration

public static bool MatchFileName(string pstrPathString, string pstrRegExpToMatch)

Parameters

Type	Name	Description
System.String	pstrPathString	Specify the path string to match against PCRE pstrRegExpToMatch.
System.String	pstrRegExpToMatch	Specify the Perl Compatible Regular Expression against which to evaluate pstrFileName.

Returns

Type	Description
System.Boolean	The function returns TRUE if neither string is null or empty AND pstrRegExpToMatch matches PCRE pstrFileName.

Remarks

This method could have been coded inline. However, since I have at least one other project in the works that requires it, I segregated it in this routine in this small, easily navigable class.

MatchHTMLPageTitleAttribute()

Expression to match the Title attribute of an ASP.NET page.

Declaration

public static string MatchHTMLPageTitleAttribute()

Returns

Type	Description
System.String