VbaPcre2

PCRE2 Regular Expression (Regex) Library Wrapper for TwinBasic and Microsoft Visual Basic For Applications (VBA 32+64 bit)

This project inherits the source code from VbPcre2 of Mr. @jpbro

https://github.com/jpbro/VbPcre2

The project related licenses are clearly stated in the Repo.

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Project objectives

Previously mentioned Mr. @jpbro:

The secondary goal of this project is to be a drop-in replacement for the VBScript.RegExp object.

Also makes the Pcre2 library work in TwinBasic and VBA (Excel, Word, PowerPoint, Outlook Mail, ...)

Outstanding features added to the project:

• Inherit the syntax SubMatches instead of SubMatchValue.

• Add string retrieval from named group with position return function IndexByName in IRegExp Class, return position in group SubMatches.

  If you are familiar with the setting in VBScript.RegExp as Global, MultiLine, change it to GlobalSearch, Options.Compile.MultiLine

VBA Example Code:

Sub test1()
  Dim re As IRegExp, m As Object
  Set re = New IRegExp
  re.Pattern = "(?<numbers>123).+?(?<chars>abc).+?(?<sign>@@@)"
  re.GlobalSearch = True  ' not use: re.Global = True
  re.Options.Compile.Multiline = True ' not use: re.Multiline = True
  Set m = re.Execute("123  abc  @@@")
  Debug.Print "          Match count: "; m.count
  Debug.Print "           Match Text: "; m(0)
  Debug.Print "   Match - FirstIndex: "; m(0).FirstIndex
  Debug.Print "    Match - LastIndex: "; m(0).LastIndex
  Debug.Print "          SubMatch[1]: "; m(0).SubMatches(1)
  Debug.Print "SubMatch - FirstIndex: "; m(0).SubMatchFirstIndex(1)
  Debug.Print " SubMatch - LastIndex: "; m(0).SubMatchLastIndex(1)
  Debug.Print "  SubMatch['numbers']: "; m(0).SubMatches(re.IndexByName("numbers"))
End Sub

****** The Pcre2 library does not support the Unicode syntax \uXXXX as in Javascript and VBScript, please convert it to \x{XXXX}.

Here are some common modern syntaxes in PCRE2, not found in VBScript.RegExp:

By leveraging the Pcre2 library, PCRE2 supports many modern syntaxes, including asymmetric groups ((?>...)), character class options (e.g., (?i)), Unicode property alternative names (\p{...}), nested options ((?i:...)), whitespace wildcards (\s), and time suffix types (\d{1,2}).

• Possessive Groups: (?>...) groups sub-expressions together without allowing backtracks, which improves performance.
• Character class options: Use (?i) to enable case-insensitive mode in that sub-expression, (?m) for multi-line mode, and (?s) for viewing every character as part of a line.
• Unicode property alternative names: Use \p{<name>} or \P{<name>} to match characters with specific Unicode properties (e.g., \p{Lu} for uppercase).
• Nested Options: (?i:abc) applies case-insensitive options to that subgroup only.
• Characters representing whitespace and words: \s matches any whitespace character (including non-ASCII characters), and \w matches any word character.
• Time-based quantifiers: Allows you to quantify a sample over a given period of time.
• Backreference separation: \1 references the contents of the group capturing number 1.

• Positive Lookahead : (?=...) matches when the pattern followed by the pattern in parentheses.
• Negative Lookahead : (?!...) matches when the pattern that follows is not the pattern in parentheses.
• Positive Lookbehind : (?<=...) matches when the preceding pattern is the pattern in parentheses.
• Negative Lookbehind : (?<!...) matches when the preceding pattern is not the pattern in parentheses.

Recursion

Syntaxes: (?R), (?0), (?1), (?&name).

• Unnamed recursion ((?R)): When you use (?R) in a pattern, it will call the same pattern again from the beginning. This is useful for structures that can be infinitely nested, like parentheses or tree structures.
• Named recursion ((?&name)):If you have named a repeating group using (?<name>...), you can recall that group using (?&name).