mirror of https://github.com/arendst/Tasmota.git
49 lines
1.9 KiB
Plaintext
49 lines
1.9 KiB
Plaintext
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What is re1.5?
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==============
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re1 (http://code.google.com/p/re1/) is "toy regular expression implementation"
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by Russel Cox, featuring simplicity and minimal code size unheard of in other
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implementations. re2 (http://code.google.com/p/re2/) is "an efficient,
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principled regular expression library" by the same author. It is robust,
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full-featured, and ... bloated, comparing to re1.
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re1.5 is an attempt to start with re1 codebase and add features required for
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minimalistic real-world use, while sticking to the minimal code size and
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memory use.
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Why?
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====
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re1.5 is intended for use in highly constrained, e.g. embedded, environments,
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where offering familiar high-level string matching functionality is still
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beneficial.
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Features
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========
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* Like re1, re1.5 retains design where compiled expression can be executed
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(matched) by multiple backends, each with its own distinctive design and
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runtime properties (complexity and memory usage).
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* Unlike re1, regexes are compiled to memory-efficient bytecode. Exact size
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of the bytecode can be found prior to compilation (for memory allocation).
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* External API functions feature namespace prefix to improve clarity and
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avoid name clashes when integrating into other projects.
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* Matchers are NUL-char clean and take size of the input string as a param.
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* Support for quoted chars in regex.
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* Support for ^, $ assertions in regex.
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* Support for "match" vs "search" operations, as common in other regex APIs.
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* Support for named character classes: \d \D \s \S \w \W.
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TODO
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====
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* Support for repetition operator {n} and {n,m}.
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* Support for Unicode (UTF-8).
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* Support for matching flags like case-insensitive, dot matches all,
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multiline, etc.
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* Support for more assertions like \A, \Z.
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Author and License
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==================
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re1.5 is maintained by Paul Sokolovsky pfalcon at users.sourceforge.net and
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licensed under BSD license, just as the original re1.
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