YuPcre2 is a new regular expression library for Delphi with Perl syntax. Directly supports UnicodeString, AnsiString, or UCS4String, as well as UTF-8, and UTF-16.
YuPcre2 provides two matching algorithms, the standard Perl and alternative DFA algorithm:
- 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.
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.
TDIRegExSearchStreamdescendants 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.
The YuPcre2 regular expression pattern syntax is mostly compatible with Perl. It includes the following:
- 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
- Anchors and Simple Assertions
- Match Point Reset
- Atomic Groups
- Option Setting
- Newline Convention
- What \R Matches
- Lookahead and Lookbehind Assertions
- Subroutine References (possibly recursive)
- Conditional Patterns
- Backtracking Control
YuPcre2 RegEx2 String Processing
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.
Replacereturns the original subject string with matches replaced, similar to but more flexible than Delphi's StringReplace() function.
Listcollects all string matches into a single string. It extracts multiple phone numbers, e-mail addresses, or URLs, with a single call.
YuPcre2 RegEx2 MaskControls
YuPcre2 includes two regular expression mask edits:
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 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 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.
YuPcre2 1.10.0 – 7 Mar 2019:
TDIRegEx2_16.Replacedid not return the start of the string if StartOffset > 0.
TDIRegEx2SearchStream_Encto DIConverters 1.18.0: Converter functions now use the native unsigned integer type for the length of a string and support stings longer than 2 GB. This change only affects projects using DIConverters 1.18.0.