diff options
| -rw-r--r-- | libbuild2/functions-builtin.cxx | 60 | ||||
| -rw-r--r-- | tests/function/builtin/testscript | 25 |
2 files changed, 84 insertions, 1 deletions
diff --git a/libbuild2/functions-builtin.cxx b/libbuild2/functions-builtin.cxx index 13b315c..e24ff8e 100644 --- a/libbuild2/functions-builtin.cxx +++ b/libbuild2/functions-builtin.cxx @@ -101,6 +101,64 @@ namespace build2 // f["empty"] += [](value* v) {return v->null || v->empty ();}; + + // $first(<value>[, <not_pair>]) + // $second(<value>[, <not_pair>]) + // + // Return the first or the second half of a pair, respectively. If a value + // is not a pair, then return `null` unless the <not_pair> argument is + // `true`, in which case return the non-pair value. + // + // If multiple pairs are specified, then return the list of first/second + // halfs. If an element is not a pair, then omit it from the resulting + // list unless the <not_pair> argument is `true`, in which case add the + // non-pair element to the list. + // + f["first"] += [] (names ns, optional<value> not_pair) + { + // @@ TODO: would be nice to return typed half if passed typed value. + + bool np (not_pair && convert<bool> (move (*not_pair))); + + names r; + for (auto i (ns.begin ()), e (ns.end ()); i != e; ) + { + name& f (*i++); + name* s (f.pair ? &*i++ : nullptr); + + if (s != nullptr || np) + { + f.pair = '\0'; + r.push_back (move (f)); + } + else if (ns.size () == 1) + return value (nullptr); // Single non-pair. + } + + return value (move (r)); + }; + + f["second"] += [] (names ns, optional<value> not_pair) + { + bool np (not_pair && convert<bool> (move (*not_pair))); + + names r; + for (auto i (ns.begin ()), e (ns.end ()); i != e; ) + { + name& f (*i++); + name* s (f.pair ? &*i++ : nullptr); + + if (s != nullptr) + r.push_back (move (*s)); + else if (np) + r.push_back (move (f)); + else if (ns.size () == 1) + return value (nullptr); // Single non-pair. + } + + return value (move (r)); + }; + // Leave this one undocumented for now since it's unclear why would anyone // want to use it currently (we don't yet have any function composition // facilities). @@ -110,7 +168,7 @@ namespace build2 // $quote(<value>[, <escape>]) // // Quote the value returning its string representation. If <escape> is - // true, then also escape (with a backslash) the quote characters being + // `true`, then also escape (with a backslash) the quote characters being // added (this is useful if the result will be re-parsed, for example as a // script command line). // diff --git a/tests/function/builtin/testscript b/tests/function/builtin/testscript index 714a38d..88f802a 100644 --- a/tests/function/builtin/testscript +++ b/tests/function/builtin/testscript @@ -55,6 +55,31 @@ $* <'print $empty([bool] false)' >'false' : bool } +: first-second +: +{ + $* <'print $first(a@1)' >'a' : first + $* <'print $second(a@1)' >'1' : second + + $* <'print $first(@1)' >'{}' : first-empty + $* <'print $second(a@)' >'{}' : second-empty + + $* <'print $first(1)' >'[null]' : first-null + $* <'print $second(a)' >'[null]' : second-null + + $* <'print $first(1, true)' >'1' : first-all + $* <'print $second(a, true)' >'a' : second-all + + $* <'print $first(0 a@1 b@2 c@ 4)' >'a b c' : firsts + $* <'print $second(z a@1 b@2 @3 d)' >'1 2 3' : seconds + + $* <'print $first(0 a@1 b@2 c@ 4, true)' >'0 a b c 4' : firsts-all + $* <'print $second(z a@1 b@2 @3 d, true)' >'z 1 2 3 d' : seconds-all + + $* <'print $first([name_pair] a@1)' >'a' : first-typed + $* <'print $second([name_pair] a@1)' >'1' : second-typed +} + : identity : { |