From 976df480c918f050608f7a23a4a21415c43475c3 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <eelco.dolstra@logicblox.com>
Date: Tue, 25 Nov 2014 11:47:06 +0100
Subject: Add a primop for regular expression pattern matching
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The function ‘builtins.match’ takes a POSIX extended regular
expression and an arbitrary string. It returns ‘null’ if the string
does not match the regular expression. Otherwise, it returns a list
containing substring matches corresponding to parenthesis groups in
the regex. The regex must match the entire string (i.e. there is an
implied "^<pat>$" around the regex).  For example:

  match "foo" "foobar" => null
  match "foo" "foo" => []
  match "f(o+)(.*)" "foooobar" => ["oooo" "bar"]
  match "(.*/)?([^/]*)" "/dir/file.nix" => ["/dir/" "file.nix"]
  match "(.*/)?([^/]*)" "file.nix" => [null "file.nix"]

The following example finds all regular files with extension .nix or
.patch underneath the current directory:

  let

    findFiles = pat: dir: concatLists (mapAttrsToList (name: type:
      if type == "directory" then
        findFiles pat (dir + "/" + name)
      else if type == "regular" && match pat name != null then
        [(dir + "/" + name)]
      else []) (readDir dir));

  in findFiles ".*\\.(nix|patch)" (toString ./.)
---
 tests/lang/eval-okay-regex-match.exp |  1 +
 tests/lang/eval-okay-regex-match.nix | 26 ++++++++++++++++++++++++++
 2 files changed, 27 insertions(+)
 create mode 100644 tests/lang/eval-okay-regex-match.exp
 create mode 100644 tests/lang/eval-okay-regex-match.nix

(limited to 'tests')

diff --git a/tests/lang/eval-okay-regex-match.exp b/tests/lang/eval-okay-regex-match.exp
new file mode 100644
index 000000000000..27ba77ddaf61
--- /dev/null
+++ b/tests/lang/eval-okay-regex-match.exp
@@ -0,0 +1 @@
+true
diff --git a/tests/lang/eval-okay-regex-match.nix b/tests/lang/eval-okay-regex-match.nix
new file mode 100644
index 000000000000..ae6501532d11
--- /dev/null
+++ b/tests/lang/eval-okay-regex-match.nix
@@ -0,0 +1,26 @@
+with builtins;
+
+let
+
+  matches = pat: s: match pat s != null;
+
+  splitFN = match "((.*)/)?([^/]*)\\.(nix|cc)";
+
+in
+
+assert  matches "foobar" "foobar";
+assert  matches "fo*" "f";
+assert !matches "fo+" "f";
+assert  matches "fo*" "fo";
+assert  matches "fo*" "foo";
+assert  matches "fo+" "foo";
+assert  matches "fo{1,2}" "foo";
+assert !matches "fo{1,2}" "fooo";
+assert !matches "fo*" "foobar";
+
+assert match "(.*)\\.nix" "foobar.nix" == [ "foobar" ];
+
+assert splitFN "/path/to/foobar.nix" == [ "/path/to/" "/path/to" "foobar" "nix" ];
+assert splitFN "foobar.cc" == [ null null "foobar" "cc" ];
+
+true
-- 
cgit 1.4.1