Add builtins.string function.
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" ] " " ]; ```
This commit is contained in:
parent
f76e85d8f5
commit
b8867a0239
|
@ -873,6 +873,43 @@ builtins.sort builtins.lessThan [ 483 249 526 147 42 77 ]
|
|||
</varlistentry>
|
||||
|
||||
|
||||
<varlistentry><term><function>builtins.split</function>
|
||||
<replaceable>regex</replaceable> <replaceable>str</replaceable></term>
|
||||
|
||||
<listitem><para>Returns a list composed of non matched strings interleaved
|
||||
with the lists of the <link
|
||||
xlink:href="http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap09.html#tag_09_04">extended
|
||||
POSIX regular expression</link> <replaceable>regex</replaceable> matches
|
||||
of <replaceable>str</replaceable>. Each item in the lists of matched
|
||||
sequences is a regex group.
|
||||
|
||||
<programlisting>
|
||||
builtins.split "(a)b" "abc"
|
||||
</programlisting>
|
||||
|
||||
Evaluates to <literal>[ "" [ "a" ] "c" ]</literal>.
|
||||
|
||||
<programlisting>
|
||||
builtins.split "([ac])" "abc"
|
||||
</programlisting>
|
||||
|
||||
Evaluates to <literal>[ "" [ "a" ] "b" [ "c" ] "" ]</literal>.
|
||||
|
||||
<programlisting>
|
||||
builtins.split "(a)|(c)" "abc"
|
||||
</programlisting>
|
||||
|
||||
Evaluates to <literal>[ "" [ "a" null ] "b" [ null "c" ] "" ]</literal>.
|
||||
|
||||
<programlisting>
|
||||
builtins.split "([[:upper:]]+)" " FOO "
|
||||
</programlisting>
|
||||
|
||||
Evaluates to <literal>[ " " [ "FOO" ] " " ]</literal>.
|
||||
|
||||
</para></listitem>
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry><term><function>builtins.stringLength</function>
|
||||
<replaceable>e</replaceable></term>
|
||||
|
||||
|
|
|
@ -1745,6 +1745,73 @@ static void prim_match(EvalState & state, const Pos & pos, Value * * args, Value
|
|||
}
|
||||
|
||||
|
||||
/* Split a string with a regular expression, and return a list of the
|
||||
non-matching parts interleaved by the lists of the matching groups. */
|
||||
static void prim_split(EvalState & state, const Pos & pos, Value * * args, Value & v)
|
||||
{
|
||||
auto re = state.forceStringNoCtx(*args[0], pos);
|
||||
|
||||
try {
|
||||
|
||||
std::regex regex(re, std::regex::extended);
|
||||
|
||||
PathSet context;
|
||||
const std::string str = state.forceString(*args[1], context, pos);
|
||||
|
||||
auto begin = std::sregex_iterator(str.begin(), str.end(), regex);
|
||||
auto end = std::sregex_iterator();
|
||||
|
||||
// Any matches results are surrounded by non-matching results.
|
||||
const size_t len = std::distance(begin, end);
|
||||
state.mkList(v, 2 * len + 1);
|
||||
size_t idx = 0;
|
||||
Value * elem;
|
||||
|
||||
if (len == 0) {
|
||||
v.listElems()[idx++] = args[1];
|
||||
return;
|
||||
}
|
||||
|
||||
for (std::sregex_iterator i = begin; i != end; ++i) {
|
||||
assert(idx <= 2 * len + 1 - 3);
|
||||
std::smatch match = *i;
|
||||
|
||||
// Add a string for non-matched characters.
|
||||
elem = v.listElems()[idx++] = state.allocValue();
|
||||
mkString(*elem, match.prefix().str().c_str());
|
||||
|
||||
// Add a list for matched substrings.
|
||||
const size_t slen = match.size() - 1;
|
||||
elem = v.listElems()[idx++] = state.allocValue();
|
||||
|
||||
// Start at 1, beacause the first match is the whole string.
|
||||
state.mkList(*elem, slen);
|
||||
for (size_t si = 0; si < slen; ++si) {
|
||||
if (!match[si + 1].matched)
|
||||
mkNull(*(elem->listElems()[si] = state.allocValue()));
|
||||
else
|
||||
mkString(*(elem->listElems()[si] = state.allocValue()), match[si + 1].str().c_str());
|
||||
}
|
||||
|
||||
// Add a string for non-matched suffix characters.
|
||||
if (idx == 2 * len) {
|
||||
elem = v.listElems()[idx++] = state.allocValue();
|
||||
mkString(*elem, match.suffix().str().c_str());
|
||||
}
|
||||
}
|
||||
assert(idx == 2 * len + 1);
|
||||
|
||||
} catch (std::regex_error &e) {
|
||||
if (e.code() == std::regex_constants::error_space) {
|
||||
// limit is _GLIBCXX_REGEX_STATE_LIMIT for libstdc++
|
||||
throw EvalError("memory limit exceeded by regular expression '%s', at %s", re, pos);
|
||||
} else {
|
||||
throw EvalError("invalid regular expression '%s', at %s", re, pos);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
static void prim_concatStringSep(EvalState & state, const Pos & pos, Value * * args, Value & v)
|
||||
{
|
||||
PathSet context;
|
||||
|
@ -2039,6 +2106,7 @@ void EvalState::createBaseEnv()
|
|||
addPrimOp("__unsafeDiscardOutputDependency", 1, prim_unsafeDiscardOutputDependency);
|
||||
addPrimOp("__hashString", 2, prim_hashString);
|
||||
addPrimOp("__match", 2, prim_match);
|
||||
addPrimOp("__split", 2, prim_split);
|
||||
addPrimOp("__concatStringsSep", 2, prim_concatStringSep);
|
||||
addPrimOp("__replaceStrings", 3, prim_replaceStrings);
|
||||
|
||||
|
|
48
tests/lang/eval-okay-regex-split.nix
Normal file
48
tests/lang/eval-okay-regex-split.nix
Normal file
|
@ -0,0 +1,48 @@
|
|||
with builtins;
|
||||
|
||||
# Non capturing regex returns empty lists
|
||||
assert split "foobar" "foobar" == ["" [] ""];
|
||||
assert split "fo*" "f" == ["" [] ""];
|
||||
assert split "fo+" "f" == ["f"];
|
||||
assert split "fo*" "fo" == ["" [] ""];
|
||||
assert split "fo*" "foo" == ["" [] ""];
|
||||
assert split "fo+" "foo" == ["" [] ""];
|
||||
assert split "fo{1,2}" "foo" == ["" [] ""];
|
||||
assert split "fo{1,2}" "fooo" == ["" [] "o"];
|
||||
assert split "fo*" "foobar" == ["" [] "bar"];
|
||||
|
||||
# Capturing regex returns a list of sub-matches
|
||||
assert split "(fo*)" "f" == ["" ["f"] ""];
|
||||
assert split "(fo+)" "f" == ["f"];
|
||||
assert split "(fo*)" "fo" == ["" ["fo"] ""];
|
||||
assert split "(f)(o*)" "f" == ["" ["f" ""] ""];
|
||||
assert split "(f)(o*)" "foo" == ["" ["f" "oo"] ""];
|
||||
assert split "(fo+)" "foo" == ["" ["foo"] ""];
|
||||
assert split "(fo{1,2})" "foo" == ["" ["foo"] ""];
|
||||
assert split "(fo{1,2})" "fooo" == ["" ["foo"] "o"];
|
||||
assert split "(fo*)" "foobar" == ["" ["foo"] "bar"];
|
||||
|
||||
# Matches are greedy.
|
||||
assert split "(o+)" "oooofoooo" == ["" ["oooo"] "f" ["oooo"] ""];
|
||||
|
||||
# Matches multiple times.
|
||||
assert split "(b)" "foobarbaz" == ["foo" ["b"] "ar" ["b"] "az"];
|
||||
|
||||
# Split large strings containing newlines. null are inserted when a
|
||||
# pattern within the current did not match anything.
|
||||
assert split "[[:space:]]+|([',.!?])" ''
|
||||
Nix Rocks!
|
||||
That's why I use it.
|
||||
'' == [
|
||||
"Nix" [ null ] "Rocks" ["!"] "" [ null ]
|
||||
"That" ["'"] "s" [ null ] "why" [ null ] "I" [ null ] "use" [ null ] "it" ["."] "" [ null ]
|
||||
""
|
||||
];
|
||||
|
||||
# Documentation examples
|
||||
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" ] " " ];
|
||||
|
||||
true
|
Loading…
Reference in a new issue