forked from lix-project/lix
Add replaceStrings primop
This is a generalisation of replaceChars in Nixpkgs.
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@ -733,6 +733,23 @@ removeAttrs { x = 1; y = 2; z = 3; } [ "a" "x" "z" ]</programlisting>
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</varlistentry>
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<varlistentry><term><function>builtins.replaceStrings</function>
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<replaceable>from</replaceable> <replaceable>to</replaceable> <replaceable>s</replaceable></term>
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<listitem><para>Given string <replaceable>s</replaceable>, replace
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every occurrence of the strings in <replaceable>from</replaceable>
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with the corresponding string in
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<replaceable>to</replaceable>. For example,
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<programlisting>
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builtins.replaceStrings ["oo" "a"] ["a" "i"] "foobar"
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</programlisting>
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evaluates to <literal>"fabir"</literal>.</para></listitem>
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</varlistentry>
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<varlistentry><term><function>builtins.seq</function>
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<replaceable>e1</replaceable> <replaceable>e2</replaceable></term>
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@ -1519,7 +1519,7 @@ static void prim_concatStringSep(EvalState & state, const Pos & pos, Value * * a
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PathSet context;
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auto sep = state.forceString(*args[0], context, pos);
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state.forceList(*args[1]);
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state.forceList(*args[1], pos);
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string res;
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res.reserve((args[1]->listSize() + 32) * sep.size());
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@ -1534,6 +1534,41 @@ static void prim_concatStringSep(EvalState & state, const Pos & pos, Value * * a
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}
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static void prim_replaceStrings(EvalState & state, const Pos & pos, Value * * args, Value & v)
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{
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state.forceList(*args[0], pos);
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state.forceList(*args[1], pos);
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if (args[0]->listSize() != args[1]->listSize())
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throw EvalError(format("‘from’ and ‘to’ arguments to ‘replaceStrings’ have different lengths, at %1%") % pos);
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Strings from;
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for (unsigned int n = 0; n < args[0]->listSize(); ++n)
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from.push_back(state.forceStringNoCtx(*args[0]->listElems()[n], pos));
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Strings to;
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for (unsigned int n = 0; n < args[1]->listSize(); ++n)
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to.push_back(state.forceStringNoCtx(*args[1]->listElems()[n], pos));
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PathSet context;
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auto s = state.forceString(*args[2], context, pos);
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string res;
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for (size_t p = 0; p < s.size(); ) {
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bool found = false;
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for (auto i = from.begin(), j = to.begin(); i != from.end(); ++i, ++j)
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if (s.compare(p, i->size(), *i) == 0) {
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found = true;
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p += i->size();
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res += *j;
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break;
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}
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if (!found) res += s[p++];
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}
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mkString(v, res, context);
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}
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/*************************************************************
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* Versions
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*************************************************************/
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@ -1741,6 +1776,7 @@ void EvalState::createBaseEnv()
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addPrimOp("__hashString", 2, prim_hashString);
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addPrimOp("__match", 2, prim_match);
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addPrimOp("__concatStringsSep", 2, prim_concatStringSep);
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addPrimOp("__replaceStrings", 3, prim_replaceStrings);
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// Versions
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addPrimOp("__parseDrvName", 1, prim_parseDrvName);
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1
tests/lang/eval-okay-replacestrings.exp
Normal file
1
tests/lang/eval-okay-replacestrings.exp
Normal file
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@ -0,0 +1 @@
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[ "faabar" "fbar" "fubar" "faboor" "fubar" ]
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8
tests/lang/eval-okay-replacestrings.nix
Normal file
8
tests/lang/eval-okay-replacestrings.nix
Normal file
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@ -0,0 +1,8 @@
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with builtins;
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[ (replaceStrings ["o"] ["a"] "foobar")
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(replaceStrings ["o"] [""] "foobar")
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(replaceStrings ["oo"] ["u"] "foobar")
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(replaceStrings ["oo" "a"] ["a" "oo"] "foobar")
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(replaceStrings ["oo" "oo"] ["u" "i"] "foobar")
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]
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