package re

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

Install

Dune Dependency

github.com Readme Changelog LGPL-2.0 with OCaml linking exception License Edit opam file Versions (23)

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@gmail.com

Sources

re-1.10.3.tbz
sha256=846546967f3fe31765935dd40a6460a9424337ecce7b12727fcba49480790ebb
sha512=d02103b7b8b8d8bc797341dcc933554745427f3c1b51b54b4ac9ff81badfd68c94726c57548b08e00ca99f3e09741b54b6500e97c19fc0e8fcefd6dfbe71da7f

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)

Published: 17 Sep 2021

README

Description

Re is a regular expression library for OCaml.

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 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 (3)

  1. seq
  2. dune >= "2.0"
  3. ocaml >= "4.02"

Dev Dependencies (1)

  1. ounit with-test

  1. alcotest < "0.4.3" | >= "1.0.0"
  2. alcotest-async >= "1.3.0"
  3. alcotest-lwt >= "1.3.0"
  4. alcotest-mirage >= "1.3.0"
  5. atd >= "2.2.1"
  6. atdd
  7. atdgen >= "2.3.3"
  8. atdgen-runtime = "2.2.1"
  9. atdj >= "2.2.1" & < "20151001.01"
  10. atdpy >= "2.4.1"
  11. atds < "2.3.3"
  12. atdts
  13. aws-config
  14. awsm-codegen
  15. BetterErrors
  16. bap < "1.0.0"
  17. bap-byteweight-frontend
  18. bap-callgraph-collator
  19. bap-fsi-benchmark
  20. bap-ida
  21. bap-objdump < "1.4.0" | >= "1.6.0"
  22. bap-print >= "2.2.0"
  23. bap-radare2
  24. bap-server
  25. benchpress
  26. bio_io >= "0.5.1"
  27. biocaml = "0.4.0" | >= "0.8.0"
  28. bistro = "0.5.0"
  29. bonsai >= "v0.15.0"
  30. bulletml
  31. calculon >= "0.2"
  32. calculon-web
  33. caldav
  34. calendar >= "3.0.0"
  35. camlp5 >= "8.00.05" & < "8.02.01"
  36. camyll
  37. caqti >= "1.7.0"
  38. catala
  39. ccss >= "1.6"
  40. cinaps >= "v0.10.0"
  41. cohttp
  42. coin
  43. colibri2
  44. conan < "0.0.5"
  45. core_bench >= "v0.9.0"
  46. core_extended >= "v0.10.0"
  47. cosovo
  48. cow < "1.2.2"
  49. cowabloga >= "0.4.0"
  50. cucumber
  51. cuid
  52. current
  53. current_web >= "0.4"
  54. daypack-lib
  55. debian-formats
  56. decompress >= "0.8" & < "1.0.0"
  57. dkml-install-installer >= "0.4.0"
  58. dns < "4.0.0"
  59. dog < "0.2.1"
  60. doi2bib >= "0.5.1"
  61. dose
  62. dose3
  63. dune-release >= "0.2.0"
  64. duppy >= "0.9.4"
  65. elpi
  66. expect_test_helpers_core
  67. expect_test_helpers_kernel
  68. ez_file
  69. ez_search
  70. fat-filesystem != "0.12.0"
  71. frag
  72. gensqlite
  73. git < "1.3.0" | >= "1.9.0" & < "1.10.0"
  74. git-split < "1.0.0"
  75. git_split
  76. gpiod
  77. graphql_parser >= "0.11.0"
  78. hardcaml_verify
  79. hardcaml_waveterm
  80. hardcaml_xilinx_components
  81. hlarp >= "0.0.3"
  82. horned_worm
  83. http_router
  84. humane-re
  85. icalendar
  86. imaplet-lwt >= "0.1.9"
  87. index
  88. index-bench
  89. irmin != "0.8.1" & < "0.10.0" | >= "1.0.0" & < "1.2.0"
  90. irmin-bench >= "2.4.0"
  91. iso-filesystem
  92. jingoo >= "1.2.21"
  93. js_of_ocaml >= "3.10.0"
  94. js_of_ocaml-compiler >= "3.10.0"
  95. js_of_ocaml-lwt >= "3.10.0"
  96. js_of_ocaml-ocamlbuild >= "3.10.0" & < "5.0"
  97. js_of_ocaml-ppx >= "3.10.0"
  98. js_of_ocaml-ppx_deriving_json >= "3.10.0"
  99. js_of_ocaml-toplevel >= "3.10.0"
  100. js_of_ocaml-tyxml >= "3.10.0"
  101. jwt
  102. jwto
  103. kappa-library
  104. kubecaml
  105. labrys
  106. ldap >= "2.5.1"
  107. learn-ocaml >= "0.13.0"
  108. libres3 >= "0.3"
  109. lipsum
  110. magic-trace
  111. mbr-format < "1.0.0"
  112. mdx
  113. message-switch
  114. mirage >= "0.10.0" & < "2.4.0"
  115. mirage-bootvar-xen < "0.3.2"
  116. mirage-www < "1.0.0"
  117. mparser-re
  118. mustache < "2.0.0"
  119. naboris
  120. netsnmp
  121. ninja_utils
  122. obelisk >= "0.5.0"
  123. ocaml-lsp-server >= "1.7.0"
  124. ocamlformat >= "0.11.0"
  125. ocamlformat-rpc < "0.21.0"
  126. ocp-build >= "1.99.21"
  127. ocp-index >= "1.0.2"
  128. ocsigen-start >= "1.7.0"
  129. octez-bls12-381-signature
  130. octez-libs
  131. odoc >= "2.0.0" & < "2.1.0"
  132. opam-bin >= "0.9.5" & < "1.1.0"
  133. opam-build-revdeps
  134. opam-client >= "2.0.0~rc2"
  135. opam-compiler
  136. opam-core
  137. opam-format >= "2.0.8" & < "2.1.0~beta2" | >= "2.1.0~rc"
  138. opam-lib
  139. opam-solver >= "2.0.8" & < "2.1.0~beta2" | >= "2.2.0~alpha"
  140. opam-state >= "2.2.0~alpha"
  141. opam2web >= "1.3.0"
  142. opam_bin_lib
  143. operf-macro
  144. opium >= "0.13.1"
  145. opium_kernel
  146. oranger
  147. ostap
  148. ozulip
  149. pa_ppx_regexp < "0.02"
  150. patdiff >= "v0.12.0"
  151. pgocaml >= "2.3"
  152. pgx
  153. plato
  154. podge >= "0.3"
  155. ppx_css < "v0.17.0"
  156. ppx_cstubs
  157. ppx_expect >= "113.33.00" & < "v0.17.0"
  158. ppx_implicits >= "0.1.0"
  159. ppx_minidebug >= "1.0.0"
  160. ppx_orakuda >= "3.0.0"
  161. ppx_regexp >= "0.3.2"
  162. ppx_sqlexpr
  163. ppx_test >= "1.1.0"
  164. ppx_tyre
  165. ppxlib >= "0.21.0"
  166. prometheus >= "0.2"
  167. prometheus-app >= "0.2"
  168. pyml_bindgen >= "0.3.1"
  169. rdf >= "0.12.0" & < "1.0.0"
  170. re_parser
  171. reason < "1.7.4"
  172. receive-mail
  173. redis >= "0.2.1"
  174. regenerate
  175. rfc1951 < "1.0.0"
  176. sarek >= "20210823"
  177. sarif >= "0.2.1"
  178. satyrographos >= "0.0.2.7"
  179. semantic_version
  180. sexp_pretty
  181. sill >= "1.3.1"
  182. simple-diff
  183. slug
  184. soupault
  185. spoc >= "20210823"
  186. sqlexpr >= "0.7.1" & < "0.9.0"
  187. swagger
  188. tar < "2.2.0"
  189. tar-format >= "0.2.0"
  190. tar-mirage < "2.2.0"
  191. tar-unix < "2.2.0"
  192. testrunner
  193. tezos-base < "7.4"
  194. tezos-clic < "8.0" | >= "13.0"
  195. tezos-protocol-compiler = "10.2" | = "13.0"
  196. tezos-stdlib-unix >= "7.4"
  197. tezt
  198. timere-parse
  199. touist >= "3.5.0"
  200. tyre >= "0.4"
  201. tyxml >= "4.0.0"
  202. tyxml-syntax
  203. uri < "4.0.0"
  204. uri-re
  205. user-agent-parser
  206. user-setup
  207. uuuu
  208. validate
  209. vendredi
  210. vhd-tool >= "0.12.0"
  211. webmachine
  212. xapi-idl
  213. xe
  214. xen-api-client >= "0.9.6"
  215. xtmpl >= "0.15.0"

Conflicts

None

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