package re

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

Install 

dune-project
 Dependency

github.com Readme Changelog LGPL-2.0-or-later WITH OCaml-LGPL-linking-exception License Edit opam file Versions (19)

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-1.10.4.tbz
sha256=83eb3e4300aa9b1dc7820749010f4362ea83524742130524d78c20ce99ca747c
sha512=92b05cf92c389fa8c753f2acca837b15dd05a4a2e8e2bec7a269d2e14c35b1a786d394258376648f80b4b99250ba1900cfe68230b8385aeac153149d9ce56099

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: 27 Apr 2022

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 >= "4.03"

Dev Dependencies (1)

  1. ounit with-test

  1. alcotest
  2. alcotest-async
  3. alcotest-lwt
  4. alcotest-mirage
  5. atd >= "2.2.1"
  6. atdcpp
  7. atdd
  8. atdgen >= "2.3.3"
  9. atdgen-runtime = "2.2.1"
  10. atdj >= "2.2.1"
  11. atdpy >= "2.4.1"
  12. atds < "2.3.3"
  13. atdts
  14. aws-config
  15. awsm-codegen
  16. BetterErrors
  17. bap-byteweight-frontend
  18. bap-callgraph-collator
  19. bap-fsi-benchmark
  20. bap-ida
  21. bap-objdump
  22. bap-print >= "2.2.0"
  23. bap-radare2
  24. benchpress
  25. bibfmt
  26. bio_io >= "0.5.1"
  27. biocaml
  28. bistro < "0.6.0"
  29. bonsai >= "v0.15.0"
  30. caisar < "4.0"
  31. calculon
  32. calculon-web
  33. caldav
  34. calendar >= "3.0.0"
  35. camlp5-buildscripts
  36. camyll
  37. caqti >= "1.7.0"
  38. catala
  39. chamo
  40. cinaps >= "v0.10.0"
  41. cohttp
  42. coin
  43. colibri2
  44. commons
  45. conan < "0.0.5"
  46. core_bench
  47. core_extended
  48. cosovo
  49. cowabloga >= "0.4.0"
  50. cucumber
  51. cuid
  52. current
  53. current_web
  54. daypack-lib
  55. debian-formats
  56. decompress < "1.0.0"
  57. dkml-install-installer >= "0.4.0"
  58. dns < "4.4.1"
  59. doi2bib
  60. dose3
  61. dune-release >= "0.2.0"
  62. dunolint-lib
  63. duppy >= "0.9.4"
  64. elpi
  65. expect_test_helpers_core
  66. expect_test_helpers_kernel
  67. ez_file
  68. ez_search
  69. fat-filesystem
  70. git-split < "1.0.0"
  71. gpiod
  72. graphql_parser >= "0.11.0"
  73. hardcaml_verify
  74. hardcaml_waveterm
  75. hardcaml_xilinx_components
  76. hlarp >= "0.0.3"
  77. horned_worm
  78. humane-re
  79. icalendar
  80. index
  81. index-bench
  82. irmin-bench
  83. jingoo >= "1.2.21"
  84. js_of_ocaml >= "3.10.0"
  85. js_of_ocaml-compiler >= "3.10.0"
  86. js_of_ocaml-lwt >= "3.10.0"
  87. js_of_ocaml-ocamlbuild >= "3.10.0" & < "5.0"
  88. js_of_ocaml-ppx >= "3.10.0"
  89. js_of_ocaml-ppx_deriving_json >= "3.10.0"
  90. js_of_ocaml-toplevel >= "3.10.0"
  91. js_of_ocaml-tyxml >= "3.10.0"
  92. jsonschema
  93. jwt
  94. jwto
  95. kappa-library
  96. kubecaml
  97. labrys
  98. ldap >= "2.5.1"
  99. learn-ocaml
  100. ledes
  101. lipsum
  102. magic-trace
  103. mdx
  104. mehari
  105. mparser-re
  106. naboris
  107. netsnmp
  108. ninja_utils
  109. nx-text
  110. obelisk >= "0.5.0"
  111. ocaml-lsp-server >= "1.9.0"
  112. ocamlformat >= "0.11.0"
  113. ocamlformat-mlx
  114. ocamlformat-rpc < "0.21.0"
  115. ocamlmig
  116. ocp-build
  117. ocp-index
  118. ocsigen-start
  119. octez-bls12-381-signature
  120. octez-libs
  121. opam-bin >= "0.9.5" & < "1.1.0"
  122. opam-client
  123. opam-compiler
  124. opam-core
  125. opam-format >= "2.0.8" & != "2.1.0~beta4"
  126. opam-lib
  127. opam-solver >= "2.0.8" & < "2.1.0" | >= "2.2.0"
  128. opam-state >= "2.2.0"
  129. opam_bin_lib
  130. opium
  131. opium_kernel
  132. oranger
  133. ostap
  134. ozulip
  135. pa_ppx_string
  136. patdiff
  137. pgocaml >= "2.3"
  138. pgx
  139. plato
  140. podge >= "0.3"
  141. ppx_css < "v0.17.0"
  142. ppx_cstubs
  143. ppx_expect < "v0.17.0"
  144. ppx_expect_nobase
  145. ppx_minidebug >= "1.6.0"
  146. ppx_regexp >= "0.3.2"
  147. ppx_test
  148. ppx_tyre
  149. ppxlib >= "0.21.1"
  150. prometheus >= "0.2"
  151. prometheus-app
  152. pyml_bindgen >= "0.3.1"
  153. rdf >= "0.12.0" & < "1.0.0"
  154. re_parser
  155. redis
  156. regenerate
  157. rfc1951 < "1.0.0"
  158. safemoney >= "0.3.0"
  159. sarek
  160. sarif >= "0.2.1"
  161. satyrographos >= "0.0.2.7"
  162. semantic_version
  163. sexp_pretty
  164. simple-diff
  165. slug
  166. snf_mcp
  167. soupault
  168. spoc
  169. swagger
  170. testo
  171. testo-lwt
  172. testo-util
  173. tezos-clic >= "16.0"
  174. tezos-stdlib-unix
  175. tezt
  176. timere-parse
  177. touist >= "3.5.0"
  178. tyre >= "0.4"
  179. tyxml >= "4.2.0"
  180. tyxml-syntax
  181. uri < "4.0.0"
  182. uri-re
  183. user-agent-parser
  184. user-setup
  185. uuuu
  186. validate
  187. vendredi
  188. wasm_of_ocaml-compiler
  189. webmachine
  190. xtmpl >= "0.18.0"

Conflicts

None

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