char[] haystack; auto r = haystack.findSplitBefore('_'); static assert(is(typeof(r.pre()) == char[])); static assert(is(typeof(r.post()) == char[])); assert(!r); assert(!r.pre); assert(!r.post); auto f()() @safe pure nothrow { char[1] x = "_"; return x[].findSplitBefore(' '); } static if (isDIP1000) static assert(!__traits(compiles, { auto _ = f(); }));
const(char)[] haystack; auto r = haystack.findSplitBefore('_'); static assert(is(typeof(r.pre()) == const(char)[])); static assert(is(typeof(r.post()) == const(char)[])); assert(!r); assert(!r.pre); assert(!r.post);
const r = "a*b".findSplitBefore('*'); assert(r); assert(r.pre == "a"); assert(r.post == "*b");
const r = "a*b".findSplitBefore('_'); assert(!r); assert(r.pre == "a*b"); assert(r.post == "");
https://forum.dlang.org/post/dhxwgtaubzbmjaqjmnmq@forum.dlang.org https://forum.dlang.org/post/zhgajqdhybtbufeiiofp@forum.dlang.org
Array-specialization of findSplitBefore with default predicate.