YuPcre2 provides two matching algorithms, the standard Perl and alternative DFA algorithm:

• The Perl algorithm is what you are used to from Perl and JavaScript. It is fast and supports the complete pattern syntax. You will likely be using it most of the time.
• DFA is a special purpose algorithm. If finds all possible matches and, in particular, it finds the longest. It never backtracks and supports partial matching better, in particular multi-segment matching of very long subject strings.

YuPcre2 has native interfaces for 8-bit, 16-bit, and 32-bit strings. Component wrappers are available for UnicodeString / WideString and AnsiString / Utf8String / RawBytestring:

Component	String Types	Comment
TDIPerlRegEx2_16	16-bit strings: UnicodeString, WideString	Full UTF-16 Unicode processing if coUtf CompileOption set.
TDIDfaRegEx2_16
TDIPerlRegEx2_8	8-bit strings: AnsiString, RawByteString, Utf8String	Full UTF-8 Unicode processing if coUtf CompileOption set.
TDIDfaRegEx2_8

The YuPcre2 RegEx2 classes descend from common ancestors which implement the core functionalities:

• Match strings and and extract full or substring matches.
• Search for regular expressions within streams and memory buffers. TDIRegExSearchStream descendants employ a buffered search within streams and files (of virtually unlimited size) and use little memory.
• Replace full matches or partial substrings.
• List full matches or partial substrings.
• Format full matches or partial substrings by adding static or dynamic text.

Users familiar with the DIRegEx might be interessted in the differences between YuPcre2 and DIRegEx.

The YuPcre2 regular expression pattern syntax is mostly compatible with Perl. It includes the following:

• Quoting
• Escaped Characters
• Character Types
• General Category Properties for \p and \P
• PCRE2 Special Category Properties for \p and \P
• Script Names for \p and \P
• Character Classes
• Quantifiers
• Anchors and Simple Assertions
• Match Point Reset
• Alternation
• Capturing
• Atomic Groups
• Comment
• Option Setting
• Newline Convention
• What \R Matches
• Lookahead and Lookbehind Assertions
• Backreferences
• Subroutine References (possibly recursive)
• Conditional Patterns
• Backtracking Control
• Callouts

YuPcre2 can Replace, List, or Format regular expressions matches or any of its substrings, useful for text editors and word processors. Variable portions of the match can be included into the result text. The full match can be referenced by number, substrings also by name. The character to introduce these reference is freely configurable. FormatOptions allow to turn features on or off as required.

• Replace returns the original subject string with matches replaced, similar to but more flexible than Delphi's StringReplace() function.
• List collects all string matches into a single string. It extracts multiple phone numbers, e-mail addresses, or URLs, with a single call.

YuPcre2 includes two regular expression mask edits: TDIRegEx2MaskEdit and TDIRegEx2ComboBox. Both controls validate keyboard input against a regular expression. They work similar to Delphi's TMaskEdit, but more flexible and powerful.

The regular expression mask edits can:

• accept / reject specific characters at determined positions;
• allow / reject particular characters if they follow defined character(s);
• restrict input text to begin / end with exact character(s);
• flag incomplete text to show that more input is needed.

Examples: Numbers, number ranges, dates, phone numbers, e-mail addresses, URLs, currency, and more.

TDIRegEx2MaskEdit

TDIRegEx2MaskEdit is an edit control that validates keyboard input on a keystroke by keystroke basis. It accepts characters entered only if the new text matches the regular expression mask pattern. If the new text does not match, the character is silently rejected.

TDIRegEx2MaskComboBox

TDIRegEx2MaskComboBox is a combo box control with essentially the same regular expression validation as TDIRegEx2MaskEdit. Additionally, it allows to select values from the combobox drop down.

The YuPcre2 RegEx2 Workbench helps to design and test regular expressions. It allows to set options, measure execution times, and to save and load settings for later use.

The YuPcre2 RegEx2 Workbench is available as

• Design-Time Component Editor and
• Standalone Application.