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 & >= "v0.17.0"

  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. k7
  110. kappa-library
  111. kubecaml
  112. lastfm >= "0.3.4"
  113. ldap >= "2.5.1"
  114. learn-ocaml
  115. ledes
  116. lipsum
  117. liquidsoap >= "2.3.3" & < "2.4.2"
  118. liquidsoap-core >= "2.3.0"
  119. liquidsoap-lang >= "2.3.0"
  120. lwt_ppx_to_let_syntax
  121. MlFront_Cli >= "2.1.4~prerel2" & < "2.3.1"
  122. MlFront_Core >= "2.4.2.30"
  123. MlFront_ZipFile
  124. magic-trace
  125. mdx
  126. mehari
  127. menhir-lsp >= "0.1.2"
  128. menhirformat
  129. mnet-cli >= "0.0.3" & < "0.0.8"
  130. mparser-re
  131. naboris
  132. netsnmp
  133. ninja_utils
  134. nx-text
  135. obelisk >= "0.5.0"
  136. ocaml-lsp-server >= "1.9.0"
  137. ocamlformat
  138. ocamlformat-mlx
  139. ocamlformat-rpc < "0.21.0"
  140. ocamlmig
  141. ocgtk < "0.1~preview2"
  142. ocp-build
  143. ocp-index
  144. ocsigen-start
  145. ocsigenserver >= "5.1.0"
  146. opam-bin >= "0.9.5" & < "1.1.0"
  147. opam-client < "2.6.0~alpha1"
  148. opam-compiler
  149. opam-core
  150. opam-format >= "2.0.8" & != "2.1.0~beta4" & < "2.6.0~alpha1"
  151. opam-lib
  152. opam-solver >= "2.0.8" & < "2.1.0" | >= "2.2.0" & < "2.6.0~alpha1"
  153. opam-state >= "2.2.0" & < "2.6.0~alpha1"
  154. opam_bin_lib
  155. opium
  156. opium_kernel
  157. oranger
  158. orun
  159. ostap
  160. oxbow
  161. ozulip
  162. pa_ppx_parsetree
  163. pa_ppx_regexp >= "0.04"
  164. pa_ppx_string
  165. parseff
  166. passage >= "0.3.2"
  167. patdiff
  168. pgocaml >= "2.3"
  169. pgx
  170. plato
  171. playwright
  172. podge >= "0.3"
  173. ppx_css < "v0.17.0"
  174. ppx_cstubs
  175. ppx_elpi
  176. ppx_expect < "v0.17.0"
  177. ppx_expect_nobase = "v0.17.2.2"
  178. ppx_mikmatch
  179. ppx_minidebug >= "1.6.0"
  180. ppx_regexp >= "0.3.2"
  181. ppx_test
  182. ppx_tyre
  183. ppxlib >= "0.21.1"
  184. prometheus >= "0.2"
  185. prometheus-app < "2.0"
  186. prometheus-reporter
  187. pyml_bindgen >= "0.3.1"
  188. raga
  189. rdf
  190. re_parser
  191. redis
  192. regrade
  193. rfc1951 < "1.0.0"
  194. safemoney >= "0.3.0"
  195. saga
  196. sarek
  197. sarif >= "0.2.1"
  198. satyrographos
  199. semantic_version
  200. sexp_pretty
  201. shakuhachi
  202. simple-diff
  203. slug
  204. smtml >= "0.21.0"
  205. snf_mcp
  206. sosie
  207. soupault
  208. spectrum >= "0.7.0"
  209. spectrum_capabilities
  210. spectrum_palette_ppx
  211. spectrum_tools
  212. spoc
  213. statocaml_profile
  214. stem
  215. swagger
  216. talon < "1.0.0~alpha3"
  217. testcontainers
  218. testo
  219. testo-lwt
  220. testo-util
  221. tezt
  222. timere-parse
  223. touist >= "3.5.0"
  224. tw
  225. tyre >= "0.4"
  226. tyxml >= "4.2.0"
  227. tyxml-ppx >= "5.0.0"
  228. tyxml-syntax
  229. unic
  230. uri < "4.0.0"
  231. uri-re
  232. user-agent-parser
  233. user-setup
  234. uuuu < "0.4.0"
  235. validate
  236. vendredi
  237. wasm_of_ocaml-compiler
  238. wax-lib
  239. webmachine
  240. wire
  241. xtmpl >= "0.18.0"

Conflicts

None