Text-Objects: Use regex to select surroundings

Fixes #925

3 files changed, 124 insertions, 116 deletions

diff --git a/src/normal.cc b/src/normal.cc
index 224319b7..a92eb257 100644
--- a/src/normal.cc
+++ b/src/normal.cc
@@ -1171,7 +1171,9 @@ void select_object(Context& context, NormalParams params)
         if (cp == 'c')
         {
             const bool info = show_auto_info_ifn(
-                "Enter object desc", "format: <open text>,<close text>",
+                "Enter object desc",
+                "format: <open regex>,<close regex>\n"
+                "        escape commas with '\\'",
                 AutoInfo::Command, context);
 
             context.input_handler().prompt(
@@ -1189,7 +1191,8 @@ void select_object(Context& context, NormalParams params)
 
                     select_and_set_last<mode>(
                         context, std::bind(select_surrounding, _1, _2,
-                                           params[0], params[1],
+                                           Regex{params[0], RegexCompileFlags::Backward},
+                                           Regex{params[1], RegexCompileFlags::Backward},
                                            count, flags));
                 });
             return;
@@ -1197,36 +1200,36 @@ void select_object(Context& context, NormalParams params)
 
         static constexpr struct SurroundingPair
         {
-            StringView opening;
-            StringView closing;
-            Codepoint name;
+            char opening;
+            char closing;
+            char name;
         } surrounding_pairs[] = {
-            { "(", ")", 'b' },
-            { "{", "}", 'B' },
-            { "[", "]", 'r' },
-            { "<", ">", 'a' },
-            { "\"", "\"", 'Q' },
-            { "'", "'", 'q' },
-            { "`", "`", 'g' },
+            { '(', ')', 'b' },
+            { '{', '}', 'B' },
+            { '[', ']', 'r' },
+            { '<', '>', 'a' },
+            { '"', '"', 'Q' },
+            { '\'', '\'', 'q' },
+            { '`', '`', 'g' },
         };
         auto pair_it = find_if(surrounding_pairs,
                                [cp](const SurroundingPair& s) {
-                                   return s.opening[0_char] == cp or
-                                          s.closing[0_char] == cp or
+                                   return s.opening == cp or s.closing == cp or
                                           (s.name != 0 and s.name == cp);
                                });
         if (pair_it != std::end(surrounding_pairs))
             return select_and_set_last<mode>(
                 context, std::bind(select_surrounding, _1, _2,
-                                   pair_it->opening, pair_it->closing,
+                                   Regex{format("\\Q{}", pair_it->opening), RegexCompileFlags::Backward},
+                                   Regex{format("\\Q{}", pair_it->closing), RegexCompileFlags::Backward},
                                    count, flags));
 
         if (is_punctuation(cp) or cp == '_')
         {
-            auto utf8cp = to_string(cp);
+            auto re = Regex{"\\Q" + to_string(cp), RegexCompileFlags::Backward};
             return select_and_set_last<mode>(
                 context, std::bind(select_surrounding, _1, _2,
-                                   utf8cp, utf8cp, count, flags));
+                                   re, re, count, flags));
         }
     }, get_title(),
     build_autoinfo_for_mapping(context, KeymapMode::Object,
diff --git a/src/selectors.cc b/src/selectors.cc
index 63f874da..af53d0f9 100644
--- a/src/selectors.cc
+++ b/src/selectors.cc
@@ -275,40 +275,55 @@ select_matching(const Context& context, const Selection& selection)
     return {};
 }
 
-template<typename Iterator, typename Container>
-Optional<Iterator> find_closing(Iterator pos, Iterator end,
-                                Container opening, Container closing,
-                                int init_level, bool nestable)
+template<typename Iterator>
+Optional<std::pair<Iterator, Iterator>>
+find_opening(const Iterator& begin, Iterator pos,
+             const Regex& opening, const Regex& closing,
+             int level, bool nestable)
 {
-    const auto opening_len = opening.end() - opening.begin();
-    const auto closing_len = closing.end() - closing.begin();
+    MatchResults<Iterator> res;
+    if (backward_regex_search(begin, pos, res, closing) and
+        res[0].second == pos)
+        pos = res[0].first;
+
+    for (auto match : RegexIterator<Iterator, MatchDirection::Backward>{begin, pos, opening})
+    {
+        if (nestable)
+        {
+            for (auto m : RegexIterator<Iterator, MatchDirection::Backward>{match[0].second, pos, closing})
+                ++level;
+        }
 
-    int level = nestable ? init_level : 0;
+        if (not nestable or level == 0)
+            return match[0];
+        pos = match[0].first;
+        --level;
+    }
+    return {};
+}
 
-    if (end - pos >= opening_len and
-        std::equal(opening.begin(), opening.end(), pos))
-        pos += opening_len;
+template<typename Iterator>
+Optional<std::pair<Iterator, Iterator>>
+find_closing(Iterator pos, const Iterator& end,
+             const Regex& opening, const Regex& closing,
+             int level, bool nestable)
+{
+    MatchResults<Iterator> res;
+    if (regex_search(pos, end, res, opening) and
+        res[0].first == pos)
+        pos = res[0].second;
 
-    while (pos != end)
+    for (auto match : RegexIterator<Iterator, MatchDirection::Forward>{pos, end, closing})
     {
-        auto close = std::search(pos, end, closing.begin(), closing.end());
-        if (close == end)
-            return {};
-
         if (nestable)
         {
-            for (auto open = pos; open != close; open += opening_len)
-            {
-                open = std::search(open, close, opening.begin(), opening.end());
-                if (open == close)
-                    break;
+            for (auto m : RegexIterator<Iterator, MatchDirection::Forward>{pos, match[0].first, opening})
                 ++level;
-            }
         }
 
-        pos = close + closing_len;
-        if (level == 0)
-            return pos-1;
+        if (not nestable or level == 0)
+            return match[0];
+        pos = match[0].second;
         --level;
     }
     return {};
@@ -317,84 +332,70 @@ Optional<Iterator> find_closing(Iterator pos, Iterator end,
 template<typename Container, typename Iterator>
 Optional<std::pair<Iterator, Iterator>>
 find_surrounding(const Container& container, Iterator pos,
-                 StringView opening, StringView closing,
-                 ObjectFlags flags, int init_level)
+                 const Regex& opening, const Regex& closing,
+                 ObjectFlags flags, int level)
 {
-    using std::begin; using std::end;
-    const bool to_begin = flags & ObjectFlags::ToBegin;
-    const bool to_end   = flags & ObjectFlags::ToEnd;
     const bool nestable = opening != closing;
 
+    // When onto the token of a non nestable block, consider it as an opening.
+    MatchResults<Iterator> matches;
+    if (not nestable and regex_search(pos, container.end(), matches, opening) and
+        matches[0].first == pos)
+        pos = matches[0].second;
+
     auto first = pos;
-    if (to_begin and opening != *pos)
+    if (flags & ObjectFlags::ToBegin)
     {
-        using RevIt = std::reverse_iterator<Iterator>;
-        auto res = find_closing(RevIt{pos+1}, RevIt{begin(container)},
-                                closing | reverse(), opening | reverse(),
-                                init_level, nestable);
-        if (not res)
+        // When positionned onto opening and searching to opening, search the parent one
+        if (nestable and first != container.begin() and not (flags & ObjectFlags::ToEnd) and
+            regex_search(first, container.end(), matches, opening) and matches[0].first == first)
+            first = utf8::previous(first, container.begin());
+
+        if (auto res = find_opening(container.begin(), first+1, opening, closing, level, nestable))
+            first = (flags & ObjectFlags::Inner) ? res->second : res->first; 
+        else
             return {};
-
-        first = res->base() - 1; 
     }
 
     auto last = pos;
-    if (to_end)
+    if (flags & ObjectFlags::ToEnd)
     {
-        auto res = find_closing(pos, end(container), opening, closing,
-                                init_level, nestable);
-        if (not res)
+        // When positionned onto closing and searching to closing, search the parent one
+        auto next = utf8::next(last, container.end());
+        if (nestable and next != container.end() and not (flags & ObjectFlags::ToBegin) and
+            backward_regex_search(container.begin(), next, matches, closing) and matches[0].second == next)
+            last = next;
+
+        if (auto res = find_closing(last, container.end(), opening, closing, level, nestable))
+            last = (flags & ObjectFlags::Inner) ? utf8::previous(res->first, container.begin())
+                                                : utf8::previous(res->second, container.begin()); 
+        else
             return {};
-
-        last = *res; 
     }
+    if (first > last)
+        last = first;
 
-    if (flags & ObjectFlags::Inner)
-    {
-        if (to_begin and first != last)
-            first += (int)opening.length();
-        if (to_end and first != last)
-            last -= (int)closing.length();
-    }
-    return to_end ? std::pair<Iterator, Iterator>{first, last}
-                  : std::pair<Iterator, Iterator>{last, first};
+    return std::pair<Iterator, Iterator>{first, last};
 }
 
 Optional<Selection>
 select_surrounding(const Context& context, const Selection& selection,
-                   StringView opening, StringView closing, int level,
+                   const Regex& opening, const Regex& closing, int level,
                    ObjectFlags flags)
 {
     auto& buffer = context.buffer();
-    const bool nestable = opening != closing;
-    auto pos = selection.cursor();
-    if (not nestable or flags & ObjectFlags::Inner)
-    {
-        if (auto res = find_surrounding(buffer, buffer.iterator_at(pos),
-                                        opening, closing, flags, level))
-            return utf8_range(res->first, res->second);
-        return {};
-    }
-
-    auto c = buffer.byte_at(pos);
-    if ((flags == ObjectFlags::ToBegin and c == opening) or
-        (flags == ObjectFlags::ToEnd and c == closing))
-        ++level;
+    auto pos = buffer.iterator_at(selection.cursor());
 
-    auto res = find_surrounding(buffer, buffer.iterator_at(pos),
-                                opening, closing, flags, level);
-    if (not res)
-        return {};
-
-    Selection sel = utf8_range(res->first, res->second);
+    auto res = find_surrounding(buffer, pos, opening, closing, flags, level);
 
-    if (flags != (ObjectFlags::ToBegin | ObjectFlags::ToEnd) or
-        sel.min() != selection.min() or sel.max() != selection.max())
-        return sel;
+    // When we already had the full object selected, select its parent
+    if (res and flags == (ObjectFlags::ToBegin | ObjectFlags::ToEnd) and
+        res->first.coord() == selection.min() and res->second.coord() == selection.max())
+        res = find_surrounding(buffer, pos, opening, closing, flags, level+1);
 
-    if (auto res_parent = find_surrounding(buffer, buffer.iterator_at(pos),
-                                           opening, closing, flags, level+1))
-        return utf8_range(res_parent->first, res_parent->second);
+    if (res)
+        return (flags & ObjectFlags::ToEnd) ? utf8_range(res->first, res->second)
+                                            : utf8_range(res->second, res->first);
     return {};
 }
 
@@ -987,30 +988,34 @@ void split_selections(SelectionList& selections, const Regex& regex, int capture
 
 UnitTest test_find_surrounding{[]()
 {
-    StringView s("[salut { toi[] }]");
+    StringView s = "{foo [bar { baz[] }]}";
     auto check_equal = [&](const char* pos, StringView opening, StringView closing,
-                           ObjectFlags flags, int init_level, StringView expected) {
-        auto res = find_surrounding(s, pos, opening, closing, flags, init_level);
+                           ObjectFlags flags, int level, StringView expected) {
+        auto res = find_surrounding(s, pos,
+                                    Regex{"\\Q" + opening, RegexCompileFlags::Backward},
+                                    Regex{"\\Q" + closing, RegexCompileFlags::Backward},
+                                    flags, level);
+        kak_assert(res);
         auto min = std::min(res->first, res->second),
              max = std::max(res->first, res->second);
-        kak_assert(res and StringView{min, max+1} == expected);
+        kak_assert(StringView{min, max+1} == expected);
     };
 
-    check_equal(s.begin() + 10, '{', '}', ObjectFlags::ToBegin | ObjectFlags::ToEnd, 0, "{ toi[] }");
-    check_equal(s.begin() + 10, '[', ']', ObjectFlags::ToBegin | ObjectFlags::ToEnd | ObjectFlags::Inner, 0, "salut { toi[] }");
-    check_equal(s.begin(), '[', ']', ObjectFlags::ToBegin | ObjectFlags::ToEnd, 0, "[salut { toi[] }]");
-    check_equal(s.begin()+7, '{', '}', ObjectFlags::ToBegin | ObjectFlags::ToEnd, 0, "{ toi[] }");
-    check_equal(s.begin() + 12, '[', ']', ObjectFlags::ToBegin | ObjectFlags::ToEnd | ObjectFlags::Inner, 0, "]");
-    check_equal(s.begin() + 14, '[', ']', ObjectFlags::ToBegin | ObjectFlags::ToEnd, 0, "[salut { toi[] }]");
-    check_equal(s.begin() + 1, '[', ']', ObjectFlags::ToBegin, 0, "[s");
-
-    s = "[]";
-    check_equal(s.begin() + 1, '[', ']', ObjectFlags::ToBegin | ObjectFlags::ToEnd, 0, "[]");
-
-    s = "[*][] hehe";
-    kak_assert(not find_surrounding(s, s.begin() + 6, '[', ']', ObjectFlags::ToBegin, 0));
-
-    s = "begin tchou begin tchaa end end";
+    check_equal(s.begin() + 13, '{', '}', ObjectFlags::ToBegin | ObjectFlags::ToEnd, 0, "{ baz[] }");
+    check_equal(s.begin() + 13, '[', ']', ObjectFlags::ToBegin | ObjectFlags::ToEnd | ObjectFlags::Inner, 0, "bar { baz[] }");
+    check_equal(s.begin() + 5, '[', ']', ObjectFlags::ToBegin | ObjectFlags::ToEnd, 0, "[bar { baz[] }]");
+    check_equal(s.begin() + 10, '{', '}', ObjectFlags::ToBegin | ObjectFlags::ToEnd, 0, "{ baz[] }");
+    check_equal(s.begin() + 16, '[', ']', ObjectFlags::ToBegin | ObjectFlags::ToEnd | ObjectFlags::Inner, 0, "]");
+    check_equal(s.begin() + 18, '[', ']', ObjectFlags::ToBegin | ObjectFlags::ToEnd, 0, "[bar { baz[] }]");
+    check_equal(s.begin() + 6, '[', ']', ObjectFlags::ToBegin, 0, "[b");
+
+    s = "[*][] foo";
+    kak_assert(not find_surrounding(s, s.begin() + 6,
+                                    Regex{"\\Q[", RegexCompileFlags::Backward},
+                                    Regex{"\\Q]", RegexCompileFlags::Backward},
+                                    ObjectFlags::ToBegin, 0));
+
+    s = "begin foo begin bar end end";
     check_equal(s.begin() + 6, "begin", "end", ObjectFlags::ToBegin | ObjectFlags::ToEnd, 0, s);
 }};
 
diff --git a/src/selectors.hh b/src/selectors.hh
index 135a99dd..00bc83dd 100644
--- a/src/selectors.hh
+++ b/src/selectors.hh
@@ -109,7 +109,7 @@ void split_selections(SelectionList& selections, const Regex& regex, int capture
 
 Optional<Selection>
 select_surrounding(const Context& context, const Selection& selection,
-                   StringView opening, StringView closing, int level,
+                   const Regex& opening, const Regex& closing, int level,
                    ObjectFlags flags);
 
 }