forked from lix-project/lix
New primitives:
* `sub' to subtract two numbers. * `stringLength' to get the length of a string. * `substring' to get a substring of a string. These should be enough to allow most string operations to be expressed.
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7349bd0176
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@ -55,7 +55,10 @@
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<listitem><para>TODO: new built-ins
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<function>builtins.attrNames</function>,
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<function>builtins.filterSource</function>.</para></listitem>
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<function>builtins.filterSource</function>,
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<function>builtins.sub</function>,
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<function>builtins.stringLength</function>,
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<function>builtins.substring</function>.</para></listitem>
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</itemizedlist>
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@ -723,6 +723,14 @@ static Expr primAdd(EvalState & state, const ATermVector & args)
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}
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static Expr primSub(EvalState & state, const ATermVector & args)
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{
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int i1 = evalInt(state, args[0]);
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int i2 = evalInt(state, args[1]);
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return makeInt(i1 - i2);
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}
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static Expr primLessThan(EvalState & state, const ATermVector & args)
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{
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int i1 = evalInt(state, args[0]);
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@ -779,6 +787,36 @@ static Expr primFilterSource(EvalState & state, const ATermVector & args)
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}
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/*************************************************************
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* String manipulation
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*************************************************************/
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/* `substr start len str' returns the substring of `str' starting at
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character position `min(start, stringLength str)' inclusive and
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ending at `min(start + len, stringLength str)'. `start' must be
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non-negative. */
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static Expr prim_substring(EvalState & state, const ATermVector & args)
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{
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int start = evalInt(state, args[0]);
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int len = evalInt(state, args[1]);
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PathSet context;
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string s = coerceToString(state, args[2], context);
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if (start < 0) throw EvalError("negative start position in `substring'");
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return makeStr(string(s, start, len), context);
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}
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static Expr prim_stringLength(EvalState & state, const ATermVector & args)
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{
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PathSet context;
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string s = coerceToString(state, args[0], context);
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return makeInt(s.size());
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}
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void EvalState::addPrimOps()
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{
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addPrimOp("builtins", 0, primBuiltins);
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@ -813,10 +851,14 @@ void EvalState::addPrimOps()
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addPrimOp("removeAttrs", 2, primRemoveAttrs);
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addPrimOp("relativise", 2, primRelativise);
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addPrimOp("__add", 2, primAdd);
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addPrimOp("__sub", 2, primSub);
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addPrimOp("__lessThan", 2, primLessThan);
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addPrimOp("__toFile", 2, primToFile);
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addPrimOp("__filterSource", 2, primFilterSource);
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addPrimOp("__substring", 3, prim_substring);
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addPrimOp("__stringLength", 1, prim_stringLength);
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}
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}
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@ -4,6 +4,9 @@ derivation {
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builder = "@shell@";
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args = ["-e" "-x" (builtins.toFile "builder" "PATH=@testPath@; ln -s $input $out")];
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input =
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let filter = path: type: type != "symlink" && baseNameOf (toString path) != "foo";
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let filter = path: type:
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type != "symlink"
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&& baseNameOf path != "foo"
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&& !((import ./lang/lib.nix).hasSuffix ".bak" (baseNameOf path));
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in builtins.filterSource filter ./test-tmp/filterin;
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}
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@ -5,6 +5,9 @@ mkdir $TEST_ROOT/filterin
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mkdir $TEST_ROOT/filterin/foo
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touch $TEST_ROOT/filterin/foo/bar
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touch $TEST_ROOT/filterin/xyzzy
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touch $TEST_ROOT/filterin/b
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touch $TEST_ROOT/filterin/bak
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touch $TEST_ROOT/filterin/bla.c.bak
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ln -s xyzzy $TEST_ROOT/filterin/link
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$NIX_BIN_DIR/nix-build ./filter-source.nix -o $TEST_ROOT/filterout
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@ -12,4 +15,6 @@ $NIX_BIN_DIR/nix-build ./filter-source.nix -o $TEST_ROOT/filterout
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set -x
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test ! -e $TEST_ROOT/filterout/foo/bar
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test -e $TEST_ROOT/filterout/xyzzy
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test -e $TEST_ROOT/filterout/bak
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test ! -e $TEST_ROOT/filterout/bla.c.bak
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test ! -L $TEST_ROOT/filterout/link
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1
tests/lang/eval-fail-substring.nix
Normal file
1
tests/lang/eval-fail-substring.nix
Normal file
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@ -0,0 +1 @@
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builtins.substring (builtins.sub 0 1) 1 "x"
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1
tests/lang/eval-okay-substring.exp
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1
tests/lang/eval-okay-substring.exp
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@ -0,0 +1 @@
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Str("ooxfoobarybarzobaabb",[])
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tests/lang/eval-okay-substring.nix
Normal file
19
tests/lang/eval-okay-substring.nix
Normal file
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@ -0,0 +1,19 @@
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with builtins;
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let
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s = "foobar";
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in
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substring 1 2 s
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+ "x"
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+ substring 0 (stringLength s) s
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+ "y"
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+ substring 3 100 s
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+ "z"
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+ substring 2 (sub (stringLength s) 3) s
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+ "a"
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+ substring 3 0 s
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+ "b"
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+ substring 3 1 s
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@ -1,18 +1,26 @@
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with builtins;
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rec {
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fold = op: nul: list:
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if list == []
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then nul
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else op (builtins.head list) (fold op nul (builtins.tail list));
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else op (head list) (fold op nul (tail list));
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concat =
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fold (x: y: x + y) "";
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flatten = x:
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if builtins.isList x
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if isList x
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then fold (x: y: (flatten x) ++ y) [] x
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else [x];
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sum = fold (x: y: builtins.add x y) 0;
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sum = fold (x: y: add x y) 0;
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hasSuffix = ext: fileName:
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let lenFileName = stringLength fileName;
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lenExt = stringLength ext;
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in !(lessThan lenFileName lenExt) &&
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substring (sub lenFileName lenExt) lenFileName fileName == ext;
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}
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