b8867a0239
The function 'builtins.split' takes a POSIX extended regular expression
and an arbitrary string. It returns a list of non-matching substring
interleaved by lists of matched groups of the regular expression.
```nix
with builtins;
assert split "(a)b" "abc" == [ "" [ "a" ] "c" ];
assert split "([ac])" "abc" == [ "" [ "a" ] "b" [ "c" ] "" ];
assert split "(a)|(c)" "abc" == [ "" [ "a" null ] "b" [ null "c" ] "" ];
assert split "([[:upper:]]+)" " FOO "
== [ " " [ "FOO" ] " " ];
```
48 lines
1.8 KiB
Nix
48 lines
1.8 KiB
Nix
with builtins;
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# Non capturing regex returns empty lists
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assert split "foobar" "foobar" == ["" [] ""];
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assert split "fo*" "f" == ["" [] ""];
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assert split "fo+" "f" == ["f"];
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assert split "fo*" "fo" == ["" [] ""];
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assert split "fo*" "foo" == ["" [] ""];
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assert split "fo+" "foo" == ["" [] ""];
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assert split "fo{1,2}" "foo" == ["" [] ""];
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assert split "fo{1,2}" "fooo" == ["" [] "o"];
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assert split "fo*" "foobar" == ["" [] "bar"];
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# Capturing regex returns a list of sub-matches
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assert split "(fo*)" "f" == ["" ["f"] ""];
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assert split "(fo+)" "f" == ["f"];
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assert split "(fo*)" "fo" == ["" ["fo"] ""];
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assert split "(f)(o*)" "f" == ["" ["f" ""] ""];
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assert split "(f)(o*)" "foo" == ["" ["f" "oo"] ""];
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assert split "(fo+)" "foo" == ["" ["foo"] ""];
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assert split "(fo{1,2})" "foo" == ["" ["foo"] ""];
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assert split "(fo{1,2})" "fooo" == ["" ["foo"] "o"];
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assert split "(fo*)" "foobar" == ["" ["foo"] "bar"];
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# Matches are greedy.
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assert split "(o+)" "oooofoooo" == ["" ["oooo"] "f" ["oooo"] ""];
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# Matches multiple times.
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assert split "(b)" "foobarbaz" == ["foo" ["b"] "ar" ["b"] "az"];
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# Split large strings containing newlines. null are inserted when a
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# pattern within the current did not match anything.
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assert split "[[:space:]]+|([',.!?])" ''
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Nix Rocks!
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That's why I use it.
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'' == [
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"Nix" [ null ] "Rocks" ["!"] "" [ null ]
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"That" ["'"] "s" [ null ] "why" [ null ] "I" [ null ] "use" [ null ] "it" ["."] "" [ null ]
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""
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];
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# Documentation examples
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assert split "(a)b" "abc" == [ "" [ "a" ] "c" ];
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assert split "([ac])" "abc" == [ "" [ "a" ] "b" [ "c" ] "" ];
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assert split "(a)|(c)" "abc" == [ "" [ "a" null ] "b" [ null "c" ] "" ];
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assert split "([[:upper:]]+)" " FOO " == [ " " [ "FOO" ] " " ];
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true
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