diff options
| -rw-r--r-- | doc/manual/expressions/builtins.xml | 17 | ||||
| -rw-r--r-- | src/libexpr/primops.cc | 38 | ||||
| -rw-r--r-- | tests/lang/eval-okay-replacestrings.exp | 1 | ||||
| -rw-r--r-- | tests/lang/eval-okay-replacestrings.nix | 8 |
4 files changed, 63 insertions, 1 deletions
diff --git a/doc/manual/expressions/builtins.xml b/doc/manual/expressions/builtins.xml index cb987ca02772..099f90e786e5 100644 --- a/doc/manual/expressions/builtins.xml +++ b/doc/manual/expressions/builtins.xml @@ -733,6 +733,23 @@ removeAttrs { x = 1; y = 2; z = 3; } [ "a" "x" "z" ]</programlisting> </varlistentry> + <varlistentry><term><function>builtins.replaceStrings</function> + <replaceable>from</replaceable> <replaceable>to</replaceable> <replaceable>s</replaceable></term> + + <listitem><para>Given string <replaceable>s</replaceable>, replace + every occurrence of the strings in <replaceable>from</replaceable> + with the corresponding string in + <replaceable>to</replaceable>. For example, + +<programlisting> +builtins.replaceStrings ["oo" "a"] ["a" "i"] "foobar" +</programlisting> + + evaluates to <literal>"fabir"</literal>.</para></listitem> + + </varlistentry> + + <varlistentry><term><function>builtins.seq</function> <replaceable>e1</replaceable> <replaceable>e2</replaceable></term> diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc index c320b4c39711..ece76975d034 100644 --- a/src/libexpr/primops.cc +++ b/src/libexpr/primops.cc @@ -1519,7 +1519,7 @@ static void prim_concatStringSep(EvalState & state, const Pos & pos, Value * * a PathSet context; auto sep = state.forceString(*args[0], context, pos); - state.forceList(*args[1]); + state.forceList(*args[1], pos); string res; res.reserve((args[1]->listSize() + 32) * sep.size()); @@ -1534,6 +1534,41 @@ static void prim_concatStringSep(EvalState & state, const Pos & pos, Value * * a } +static void prim_replaceStrings(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + state.forceList(*args[0], pos); + state.forceList(*args[1], pos); + if (args[0]->listSize() != args[1]->listSize()) + throw EvalError(format("‘from’ and ‘to’ arguments to ‘replaceStrings’ have different lengths, at %1%") % pos); + + Strings from; + for (unsigned int n = 0; n < args[0]->listSize(); ++n) + from.push_back(state.forceStringNoCtx(*args[0]->listElems()[n], pos)); + + Strings to; + for (unsigned int n = 0; n < args[1]->listSize(); ++n) + to.push_back(state.forceStringNoCtx(*args[1]->listElems()[n], pos)); + + PathSet context; + auto s = state.forceString(*args[2], context, pos); + + string res; + for (size_t p = 0; p < s.size(); ) { + bool found = false; + for (auto i = from.begin(), j = to.begin(); i != from.end(); ++i, ++j) + if (s.compare(p, i->size(), *i) == 0) { + found = true; + p += i->size(); + res += *j; + break; + } + if (!found) res += s[p++]; + } + + mkString(v, res, context); +} + + /************************************************************* * Versions *************************************************************/ @@ -1741,6 +1776,7 @@ void EvalState::createBaseEnv() addPrimOp("__hashString", 2, prim_hashString); addPrimOp("__match", 2, prim_match); addPrimOp("__concatStringsSep", 2, prim_concatStringSep); + addPrimOp("__replaceStrings", 3, prim_replaceStrings); // Versions addPrimOp("__parseDrvName", 1, prim_parseDrvName); diff --git a/tests/lang/eval-okay-replacestrings.exp b/tests/lang/eval-okay-replacestrings.exp new file mode 100644 index 000000000000..a2add1b7b140 --- /dev/null +++ b/tests/lang/eval-okay-replacestrings.exp @@ -0,0 +1 @@ +[ "faabar" "fbar" "fubar" "faboor" "fubar" ] diff --git a/tests/lang/eval-okay-replacestrings.nix b/tests/lang/eval-okay-replacestrings.nix new file mode 100644 index 000000000000..6284a0e660ae --- /dev/null +++ b/tests/lang/eval-okay-replacestrings.nix @@ -0,0 +1,8 @@ +with builtins; + +[ (replaceStrings ["o"] ["a"] "foobar") + (replaceStrings ["o"] [""] "foobar") + (replaceStrings ["oo"] ["u"] "foobar") + (replaceStrings ["oo" "a"] ["a" "oo"] "foobar") + (replaceStrings ["oo" "oo"] ["u" "i"] "foobar") +] |