package re

  1. Overview
  2. Docs
RE is a regular expression library for OCaml

Install 

dune-project
 Dependency

github.com Readme Changelog LGPL-2.1-or-later WITH OCaml-LGPL-linking-exception License Edit opam file Versions (20)

Authors

  1. J
    Jerome Vouillon
  2. T
    Thomas Gazagnaire
  3. A
    Anil Madhavapeddy
  4. R
    Rudi Grinberg
  5. Gabriel Radanne

Maintainers

  1. R
    Rudi Grinberg <me@rgrinberg.com>

Sources

1.14.0.tar.gz
md5=03f4a83100cb9229a796b85c698076e1
sha512=cd2cc39f951ca6b7be631bbb5531ed13bc040e629842671bf6fef3911b20ef1653fa9a1f0aa23b094d252cffc9a9efe7ffca69e50d362ab935bc0cc447548124

Description

Pure OCaml regular expressions with:

  • Perl-style regular expressions (module Re.Perl)
  • Posix extended regular expressions (module Re.Posix)
  • Emacs-style regular expressions (module Re.Emacs)
  • Shell-style file globbing (module Re.Glob)
  • Compatibility layer for OCaml's built-in Str module (module Re.Str)

Added to opam-repository:

README

Description

Re is a regular expression library for OCaml. Build status

Contact

This library has been written by Jerome Vouillon (Jerome.Vouillon@pps.univ-paris-diderot.fr). It can be downloaded from https://github.com/ocaml/ocaml-re

Bug reports, suggestions and contributions are welcome.

Features

The following styles of regular expressions are supported:

  • Perl-style regular expressions (module Re.Perl);
  • Posix extended regular expressions (module Re.Posix);
  • Emacs-style regular expressions (module Re.Emacs);
  • Shell-style file globbing (module Re.Glob).

It is also possible to build regular expressions by combining simpler regular expressions (module Re).

The most notable missing features are back-references and look-ahead/look-behind assertions.

There is also a subset of the PCRE interface available in the Re.Pcre module. This makes it easier to port code from that library to Re with minimal changes.

Performances

The matches are performed by lazily building a DFA (deterministic finite automaton) from the regular expression. As a consequence, matching takes linear time in the length of the matched string.

The compilation of patterns is slower than with libraries using back-tracking, such as PCRE. But, once a large enough part of the DFA is built, matching is extremely fast.

Of course, for some combinations of regular expression and string, the part of the DFA that needs to be build is so large that this point is never reached, and matching will be slow. This is not expected to happen often in practice, and actually a lot of expressions that behaves badly with a backtracking implementation are very efficient with this implementation.

The library is at the moment entirely written in OCaml. As a consequence, regular expression matching is much slower when the library is compiled to bytecode than when it is compiled to native code.

Here are some timing results (Pentium III 500Mhz):

  • Scanning a 1Mb string containing only as, except for the last character which is a b, searching for the pattern aa?b (repeated 100 times):

    • RE: 2.6s
    • PCRE: 68s

  • Regular expression example from http://www.bagley.org/~doug/shootout/ [1]

    • RE: 0.43s
    • PCRE: 3.68s

    [1] this page is no longer up but is available via the Internet Archive http://web.archive.org/web/20010429190941/http://www.bagley.org/~doug/shootout/bench/regexmatch/

  • The large regular expression (about 2000 characters long) that Unison uses with my preference file to decide whether a file should be ignored or not. This expression is matched against a filename about 20000 times.

    • RE: 0.31s
    • PCRE: 3.7s However, RE is only faster than PCRE when there are more than about 300 filenames.

Dependencies (2)

  1. ocaml >= "4.13.0"
  2. dune >= "3.17"

Dev Dependencies (5)

  1. odoc with-doc
  2. conf-npm with-test
  3. js_of_ocaml with-test
  4. ounit2 with-test
  5. ppx_expect with-test

  1. alcotest
  2. alcotest-async
  3. alcotest-lwt
  4. alcotest-mirage
  5. alice
  6. atd >= "2.2.1"
  7. atd-jsonlike
  8. atdcpp
  9. atdd
  10. atdgen >= "2.3.3"
  11. atdgen-runtime = "2.2.1"
  12. atdj >= "2.2.1"
  13. atdpy >= "2.4.1"
  14. atds < "2.3.3"
  15. atdts
  16. aws-config
  17. awsm-codegen
  18. awso
  19. BetterErrors
  20. bancos
  21. bap-byteweight-frontend
  22. bap-callgraph-collator
  23. bap-fsi-benchmark
  24. bap-ida
  25. bap-objdump
  26. bap-print
  27. bap-radare2
  28. bibfmt
  29. bio_io >= "0.5.1"
  30. biocaml
  31. bonsai >= "v0.15.0"
  32. brot
  33. caisar >= "4.0"
  34. calculon
  35. calculon-web
  36. caldav
  37. calendar >= "3.0.0"
  38. camlp5 >= "8.02.01"
  39. camlp5-buildscripts
  40. camyll
  41. caqti >= "1.7.0"
  42. cascade
  43. catala
  44. catala-format >= "1.2.0"
  45. chamo
  46. ciao_lwt
  47. cinaps
  48. cohttp
  49. coin < "0.1.5"
  50. colibri2
  51. commons
  52. conan >= "0.0.6"
  53. core_bench
  54. core_extended
  55. cosovo
  56. cowabloga >= "0.4.0"
  57. crs
  58. cucumber
  59. cuid
  60. current
  61. current_web
  62. daypack-lib
  63. debian-formats
  64. decompress < "1.0.0"
  65. dns < "4.4.1"
  66. docfd >= "13.0.0"
  67. doi2bib
  68. dose3
  69. dune-glob >= "3.21.0"
  70. dune-release >= "0.2.0"
  71. dunolint >= "0.0.20251006"
  72. dunolint-lib
  73. dunolint-lib-base
  74. duppy >= "0.9.5"
  75. elpi
  76. expect >= "0.1.0"
  77. expect_test_helpers_core
  78. expect_test_helpers_kernel
  79. ez_file
  80. ez_search
  81. fat-filesystem
  82. git-split < "1.0.0"
  83. gpiod
  84. graphql_parser >= "0.11.0"
  85. hardcaml_verify
  86. hardcaml_waveterm
  87. hardcaml_xilinx_components
  88. hegel >= "0.24.1"
  89. hlarp >= "0.0.3"
  90. humane-re
  91. icalendar
  92. index
  93. index-bench
  94. irmin-bench
  95. jingoo >= "1.2.21"
  96. js_of_ocaml >= "3.10.0"
  97. js_of_ocaml-compiler >= "3.10.0"
  98. js_of_ocaml-lwt >= "3.10.0"
  99. js_of_ocaml-ocamlbuild >= "3.10.0" & < "5.0"
  100. js_of_ocaml-ppx >= "3.10.0"
  101. js_of_ocaml-ppx_deriving_json >= "3.10.0"
  102. js_of_ocaml-toplevel >= "3.10.0"
  103. js_of_ocaml-tyxml >= "3.10.0"
  104. jsonschema
  105. jsonschema-core
  106. jsonschema-validation
  107. jwt
  108. jwto
  109. kappa-library
  110. kubecaml
  111. lastfm >= "0.3.4"
  112. ldap >= "2.5.1"
  113. learn-ocaml
  114. ledes
  115. lipsum
  116. liquidsoap >= "2.3.3" & < "2.4.2"
  117. liquidsoap-core >= "2.3.0"
  118. liquidsoap-lang >= "2.3.0"
  119. lwt_ppx_to_let_syntax
  120. MlFront_Cli >= "2.1.4~prerel2" & < "2.3.1"
  121. MlFront_Core >= "2.4.2.30"
  122. MlFront_ZipFile
  123. magic-trace
  124. mdx
  125. mehari
  126. menhir-lsp >= "0.1.2"
  127. menhirformat
  128. mnet-cli >= "0.0.3"
  129. mparser-re
  130. naboris
  131. netsnmp
  132. ninja_utils
  133. nx-text
  134. obelisk >= "0.5.0"
  135. ocaml-lsp-server >= "1.9.0"
  136. ocamlformat
  137. ocamlformat-mlx
  138. ocamlformat-rpc < "0.21.0"
  139. ocamlmig
  140. ocgtk < "0.1~preview2"
  141. ocp-build
  142. ocp-index
  143. ocsigen-start
  144. ocsigenserver >= "5.1.0"
  145. opam-bin >= "0.9.5" & < "1.1.0"
  146. opam-client < "2.6.0~alpha1"
  147. opam-compiler
  148. opam-core
  149. opam-format >= "2.0.8" & != "2.1.0~beta4" & < "2.6.0~alpha1"
  150. opam-lib
  151. opam-solver >= "2.0.8" & < "2.1.0" | >= "2.2.0" & < "2.6.0~alpha1"
  152. opam-state >= "2.2.0" & < "2.6.0~alpha1"
  153. opam_bin_lib
  154. opium
  155. opium_kernel
  156. oranger
  157. orun
  158. ostap
  159. oxbow
  160. ozulip
  161. pa_ppx_parsetree
  162. pa_ppx_regexp >= "0.04"
  163. pa_ppx_string
  164. parseff
  165. passage >= "0.3.2"
  166. patdiff
  167. pgocaml >= "2.3"
  168. pgx
  169. plato
  170. playwright
  171. podge >= "0.3"
  172. ppx_css < "v0.17.0"
  173. ppx_cstubs
  174. ppx_expect < "v0.17.0"
  175. ppx_expect_nobase = "v0.17.2.2"
  176. ppx_mikmatch
  177. ppx_minidebug >= "1.6.0"
  178. ppx_regexp >= "0.3.2"
  179. ppx_test
  180. ppx_tyre
  181. ppxlib >= "0.21.1"
  182. prometheus >= "0.2"
  183. prometheus-app < "2.0"
  184. prometheus-reporter
  185. pyml_bindgen >= "0.3.1"
  186. raga
  187. rdf
  188. re_parser
  189. redis
  190. regrade
  191. rfc1951 < "1.0.0"
  192. safemoney >= "0.3.0"
  193. saga
  194. sarek
  195. sarif >= "0.2.1"
  196. satyrographos
  197. semantic_version
  198. sexp_pretty
  199. shakuhachi
  200. simple-diff
  201. slug
  202. smtml >= "0.21.0"
  203. snf_mcp
  204. sosie
  205. soupault
  206. spectrum >= "0.7.0"
  207. spectrum_capabilities
  208. spectrum_palette_ppx
  209. spectrum_tools
  210. spoc
  211. statocaml_profile
  212. stem
  213. swagger
  214. talon < "1.0.0~alpha3"
  215. testcontainers
  216. testo
  217. testo-lwt
  218. testo-util
  219. tezt
  220. timere-parse
  221. touist >= "3.5.0"
  222. tw
  223. tyre >= "0.4"
  224. tyxml >= "4.2.0"
  225. tyxml-ppx >= "5.0.0"
  226. tyxml-syntax
  227. unic
  228. uri < "4.0.0"
  229. uri-re
  230. user-agent-parser
  231. user-setup
  232. uuuu < "0.4.0"
  233. validate
  234. vendredi
  235. wasm_of_ocaml-compiler
  236. wax-lib
  237. webmachine
  238. wire
  239. xtmpl >= "0.18.0"

Conflicts

None