package re

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

Install

Dune Dependency

Authors

Maintainers

Sources

re-1.11.0.tbz
sha256=01fc244780c0f6be72ae796b1fb750f367de18624fd75d07ee79782ed6df8d4f
sha512=3e3712cc1266ec1f27620f3508ea2ebba338f4083b07d8a69dccee1facfdc1971a6c39f9deea664d2a62fd7f2cfd2eae816ca4c274acfadaee992a3befc4b757

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: 23 Aug 2023

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 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 (3)

  1. seq
  2. dune >= "2.0"
  3. ocaml >= "4.03"

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. caisar
  32. calculon >= "0.2"
  33. calculon-web
  34. caldav
  35. calendar >= "3.0.0"
  36. camlp5 >= "8.00.05"
  37. camlp5-buildscripts
  38. camyll
  39. caqti >= "1.7.0"
  40. catala
  41. ccss >= "1.6"
  42. chamo >= "4.0"
  43. cinaps >= "v0.10.0"
  44. cohttp
  45. coin
  46. colibri2
  47. commons
  48. conan >= "0.0.5"
  49. core_bench >= "v0.9.0"
  50. core_extended >= "v0.10.0"
  51. cosovo
  52. cow < "1.2.2"
  53. cowabloga >= "0.4.0"
  54. cucumber
  55. cuid
  56. current
  57. current_web >= "0.4"
  58. daypack-lib
  59. debian-formats
  60. decompress >= "0.8" & < "1.0.0"
  61. dns < "4.0.0"
  62. dog < "0.2.1"
  63. doi2bib >= "0.5.1"
  64. dose
  65. dose3
  66. dune-release >= "0.2.0"
  67. elpi
  68. expect_test_helpers_core
  69. expect_test_helpers_kernel
  70. ez_file
  71. ez_search
  72. fat-filesystem != "0.12.0"
  73. frag
  74. gensqlite
  75. git < "1.3.0" | >= "1.9.0" & < "1.10.0"
  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. learn-ocaml >= "0.13.0"
  107. libres3 >= "0.3"
  108. lipsum
  109. magic-trace
  110. mbr-format < "1.0.0"
  111. mdx
  112. mehari
  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. ocsigenserver >= "5.1.0"
  130. octez-bls12-381-signature
  131. octez-libs
  132. odoc >= "2.0.0" & < "2.1.0"
  133. opam-bin >= "0.9.5" & < "1.1.0"
  134. opam-build-revdeps
  135. opam-client >= "2.0.0~rc2"
  136. opam-compiler
  137. opam-core
  138. opam-format >= "2.0.8" & < "2.1.0~beta2" | >= "2.1.0~rc"
  139. opam-lib
  140. opam-solver >= "2.0.8" & < "2.1.0~beta2" | >= "2.2.0~alpha"
  141. opam-state >= "2.2.0~alpha"
  142. opam2web >= "1.3.0"
  143. opam_bin_lib
  144. operf-macro
  145. opium >= "0.13.1"
  146. opium_kernel
  147. oranger
  148. orun
  149. ostap
  150. ozulip
  151. pa_ppx_parsetree
  152. pa_ppx_regexp >= "0.02"
  153. pa_ppx_string
  154. patdiff >= "v0.12.0"
  155. pgocaml >= "2.3"
  156. pgx
  157. plato
  158. podge >= "0.3"
  159. ppx_css
  160. ppx_cstubs
  161. ppx_expect >= "113.33.00"
  162. ppx_implicits >= "0.1.0"
  163. ppx_minidebug >= "1.0.0"
  164. ppx_orakuda >= "3.0.0"
  165. ppx_regexp >= "0.3.2"
  166. ppx_sqlexpr
  167. ppx_test >= "1.1.0"
  168. ppx_tyre
  169. ppxlib >= "0.21.0"
  170. prometheus >= "0.2"
  171. prometheus-app >= "0.2"
  172. pyml_bindgen >= "0.3.1"
  173. rdf >= "0.12.0"
  174. re_parser
  175. reason < "1.7.4"
  176. receive-mail
  177. redis >= "0.2.1"
  178. regenerate
  179. rfc1951 < "1.0.0"
  180. sarek >= "20210823"
  181. sarif >= "0.2.1"
  182. satyrographos >= "0.0.2.7"
  183. semantic_version
  184. sexp_pretty
  185. sill >= "1.3.1"
  186. simple-diff
  187. slug
  188. soupault
  189. spoc >= "20210823"
  190. sqlexpr >= "0.7.1" & < "0.9.0"
  191. swagger
  192. tar < "2.2.0"
  193. tar-format >= "0.2.0"
  194. tar-mirage < "2.2.0"
  195. tar-unix < "2.2.0"
  196. testrunner
  197. tezos-base < "7.4"
  198. tezos-clic < "8.0" | >= "13.0"
  199. tezos-protocol-compiler = "10.2" | = "13.0"
  200. tezos-stdlib-unix >= "7.4"
  201. tezt
  202. timere-parse
  203. touist >= "3.5.0"
  204. tyre >= "0.4"
  205. tyxml >= "4.0.0"
  206. tyxml-syntax
  207. uri < "4.0.0"
  208. uri-re
  209. user-agent-parser
  210. user-setup
  211. uuuu
  212. validate
  213. vendredi
  214. vhd-tool >= "0.12.0"
  215. webmachine
  216. xapi-idl
  217. xe
  218. xen-api-client >= "0.9.6"
  219. xtmpl >= "0.15.0"

Conflicts

None