Add support for removing from options

`set -remove ...` will remove from the current option value, substracting
from int, removing elements from vectors and maps.

doc/pages/changelog.asciidoc

@@ -3,6 +3,10 @@
 This changelog contains major and/or breaking changes to Kakoune between
 released versions.
 
+== Development version
+
+* `set-option -remove` support for substracting/removing from option values
+
 == Kakoune 2020.09.01
 
 * The `repl` and `send-text` aliases have been renamed respectively into

doc/pages/options.asciidoc

@@ -10,7 +10,7 @@ scripts.
 Options can be modified using the `set-option` command:
 
 --------------------------------------------
-set-option [-add] <scope> <name> <values>...
+set-option [-add|-remove] <scope> <name> <values>...
 --------------------------------------------
 
 <scope> can be *global*, *buffer*, *window* or *current* (See
@@ -20,8 +20,9 @@ which the option is already set.
 Multiple <values> can be given as separate arguments when the option is a
 list or map.
 
-If `-add` is specified, the new value is *added* to the current one
+If `-add` or `-remove` is specified, the new value is respectively *added*
-instead of replacing it (the exact outcome depends on the type, see below).
+to or *removed* from the current one instead of replacing it (the exact
+outcome depends on the type, see below).
 
 [[unset-option]]
 Options values can be unset in a specific scope with the `unset-option`
@@ -63,7 +64,9 @@ are exclusively available to built-in options.
 
 *int*::
     an integer number.
-    `set -add` performs a math addition
+
+    `set -add` performs a math addition. +
+    `set -remove` performs a math substraction. +
 
 *bool*::
     a boolean value, yes/true or no/false
@@ -81,7 +84,10 @@ are exclusively available to built-in options.
 
 *<type>-list*::
     a list, elements are specified as separate arguments to the command.
-    `set -add` appends the new element to the list
+
+    `set -add` appends the new element to the list. +
+    `set -remove` removes each given element from the list. +
+
     Only `int-list` and `str-list` options can be created with
     `declare-option`.
 
@@ -115,7 +121,8 @@ are exclusively available to built-in options.
     its ranges get updated according to all the buffer modifications
     that happened since its timestamp.
 
-    `set -add` appends the new pair to the list
+    `set -add` appends the new pairs to the list. +
+    `set -remove` removes the given pairs from the list. +
 
     See <<highlighters#specs-highlighters,`:doc highlighters specs-highlighters`>>)
 
@@ -126,7 +133,9 @@ are exclusively available to built-in options.
     type, its lines get updated according to all the buffer modifications
     that happened since its timestamp.
     See <<highlighters#specs-highlighters,`:doc highlighters specs-highlighters`>>)
-    `set -add` appends the new spec to the list
+
+    `set -add` appends the new specs to the list. +
+    `set -remove` removes the given specs from the list. +
 
 *completions*::
     a list of `<text>|<select cmd>|<menu text>` candidates,
@@ -141,7 +150,8 @@ are exclusively available to built-in options.
     Markup can be used in the menu text.
     (see <<faces#markup-strings,`:doc faces markup-strings`>>)
 
-    `set -add` adds a new completion to the list
+    `set -add` adds given completions to the list. +
+    `set -remove` removes given completions from the list. +
 
 *enum(value1|value2|...)*::
     an enum, taking one of the given values
@@ -150,13 +160,21 @@ are exclusively available to built-in options.
 *flags(value1|value2|...)*::
     a set of flags, taking a combination of the given values joined by a
     '|' character.
-    `set -add` adds the new flag to the combination
+
+    `set -add` adds the given flags to the combination. +
+    `set -remove` removes the given flags to the combination. +
+
     Cannot be used with `declare-option`
 
 *<type>-to-<type>-map*::
     a list of `key=value` pairs.
-    `set -add` adds the new pair to the hashmap or replace an already
+
-    existing key.
+    `set -add` adds the given pair to the hashmap or replace an already
+    existing key. +
+    `set -remove` removes the given pair from the hashmap, if only the
+    key is provided it removes that entry regardless of the associated
+    value. +
+
     Only `str-to-str-map` options can be created with `declare-option`.
 
 == Builtin options

src/commands.cc

@@ -1539,7 +1539,8 @@ const CommandDesc set_option_cmd = {
     "<scope> can be global, buffer, window, or current which refers to the narrowest "
     "scope the option is set in",
     ParameterDesc{
-        { { "add", { false, "add to option rather than replacing it" } } },
+        { { "add",    { false, "add to option rather than replacing it" } },
+          { "remove", { false, "remove from option rather than replacing it" } } },
         ParameterDesc::Flags::SwitchesOnlyAtStart, 2, (size_t)-1
     },
     CommandFlags::None,
@@ -1571,9 +1572,16 @@ const CommandDesc set_option_cmd = {
     },
     [](const ParametersParser& parser, Context& context, const ShellContext&)
     {
+        bool add = (bool)parser.get_switch("add");
+        bool remove = (bool)parser.get_switch("remove");
+        if (add and remove)
+            throw runtime_error("cannot add and remove at the same time");
+
         Option& opt = get_options(parser[0], context, parser[1]).get_local_option(parser[1]);
-        if (parser.get_switch("add"))
+        if (add)
             opt.add_from_strings(parser.positionals_from(2));
+        else if (remove)
+            opt.remove_from_strings(parser.positionals_from(2));
         else
             opt.set_from_strings(parser.positionals_from(2));
     }

src/main.cc

@@ -44,6 +44,9 @@ struct {
     unsigned int version;
     StringView notes;
 } constexpr version_notes[] = { {
+        0,
+        "» {+u}set-option -remove{} support\n"
+    }, {
         20200901,
         "» daemon mode does not fork anymore\n"
     }, {

src/option.hh

@@ -43,6 +43,15 @@ option_add_from_strings(T& opt, ConstArrayView<String> strs)
     return option_add(opt, strs[0]);
 }
 
+template<typename T>
+decltype(option_add(std::declval<T>(), std::declval<String>()))
+option_remove_from_strings(T& opt, ConstArrayView<String> strs)
+{
+    if (strs.size() != 1)
+        throw runtime_error("expected a single value for option");
+    return option_remove(opt, strs[0]);
+}
+
 template<typename P, typename T>
 struct PrefixedList
 {

src/option_manager.hh

@@ -58,6 +58,7 @@ public:
     virtual String get_desc_string() const = 0;
     virtual void set_from_strings(ConstArrayView<String> strs) = 0;
     virtual void add_from_strings(ConstArrayView<String> strs) = 0;
+    virtual void remove_from_strings(ConstArrayView<String> strs) = 0;
     virtual void update(const Context& context) = 0;
 
     virtual bool has_same_value(const Option& other) const = 0;
@@ -174,6 +175,12 @@ public:
             m_manager.on_option_changed(*this);
     }
 
+    void remove_from_strings(ConstArrayView<String> strs) override
+    {
+        if (option_remove_from_strings(m_value, strs))
+            m_manager.on_option_changed(*this);
+    }
+
     void update(const Context& context) override
     {
         option_update(m_value, context);

src/option_types.hh

@@ -48,6 +48,12 @@ inline bool option_add(int& opt, StringView str)
     opt += val;
     return val != 0;
 }
+inline bool option_remove(int& opt, StringView str)
+{
+    auto val = str_to_int(str);
+    opt -= val;
+    return val != 0;
+}
 constexpr StringView option_type_name(Meta::Type<int>) { return "int"; }
 
 inline String option_to_string(size_t opt) { return to_string(opt); }
@@ -110,6 +116,21 @@ bool option_add_from_strings(Vector<T, domain>& opt, ConstArrayView<String> strs
     return not vec.empty();
 }
 
+template<typename T, MemoryDomain domain>
+bool option_remove_from_strings(Vector<T, domain>& opt, ConstArrayView<String> strs)
+{
+    bool did_remove = false;
+    for (auto&& val : strs | transform([](auto&& s) { return option_from_string(Meta::Type<T>{}, s); }))
+    {
+        auto it = find(opt, val);
+        if (it == opt.end())
+            continue;
+        opt.erase(it);
+        did_remove = true;
+    }
+    return did_remove;
+}
+
 template<typename T, MemoryDomain D>
 String option_type_name(Meta::Type<Vector<T, D>>)
 {
@@ -140,10 +161,11 @@ String option_to_string(const HashMap<Key, Value, domain>& opt, Quoting quoting)
 template<typename Key, typename Value, MemoryDomain domain>
 bool option_add_from_strings(HashMap<Key, Value, domain>& opt, ConstArrayView<String> strs)
 {
+    struct error : runtime_error { error(size_t) : runtime_error{"map option expects key=value"} {} };
+
     bool changed = false;
     for (auto&& str : strs)
     {
-        struct error : runtime_error { error(size_t) : runtime_error{"map option expects key=value"} {} };
         auto key_value = str | split<StringView>('=', '\\')
                              | transform(unescape<'=', '\\'>)
                              | static_gather<error, 2>();
@@ -154,6 +176,27 @@ bool option_add_from_strings(HashMap<Key, Value, domain>& opt, ConstArrayView<St
     return changed;
 }
 
+template<typename Key, typename Value, MemoryDomain domain>
+bool option_remove_from_strings(HashMap<Key, Value, domain>& opt, ConstArrayView<String> strs)
+{
+    struct error : runtime_error { error(size_t) : runtime_error{"map option expects key=value"} {} };
+
+    bool changed = false;
+    for (auto&& str : strs)
+    {
+        auto key_value = str | split<StringView>('=', '\\')
+                             | transform(unescape<'=', '\\'>)
+                             | static_gather<error, 2>();
+
+        if (auto it = opt.find(key_value[0]); it != opt.end() and (key_value[1].empty() or key_value[1] == it->value))
+        {
+            opt.remove(it->key);
+            changed = true;
+        }
+    }
+    return changed;
+}
+
 template<typename Key, typename Value, MemoryDomain domain>
 HashMap<Key, Value, domain> option_from_strings(Meta::Type<HashMap<Key, Value, domain>>, ConstArrayView<String> str)
 {
@@ -234,6 +277,11 @@ inline bool option_add(WorstMatch, StringView)
     throw runtime_error("no add operation supported for this option type");
 }
 
+inline bool option_remove(WorstMatch, StringView)
+{
+    throw runtime_error("no remove operation supported for this option type");
+}
+
 class Context;
 
 inline void option_update(WorstMatch, const Context&)
@@ -312,9 +360,17 @@ EnableIfWithoutBitOps<Enum, Enum> option_from_string(Meta::Type<Enum>, StringVie
 template<typename Flags, typename = decltype(enum_desc(Meta::Type<Flags>{}))>
 EnableIfWithBitOps<Flags, bool> option_add(Flags& opt, StringView str)
 {
-    const Flags res = option_from_string(Meta::Type<Flags>{}, str);
+    const Flags old = opt;
-    opt |= res;
+    opt |= option_from_string(Meta::Type<Flags>{}, str);
-    return res != (Flags)0;
+    return opt != old;
+}
+
+template<typename Flags, typename = decltype(enum_desc(Meta::Type<Flags>{}))>
+EnableIfWithBitOps<Flags, bool> option_remove(Flags& opt, StringView str)
+{
+    const Flags old = opt;
+    opt &= ~option_from_string(Meta::Type<Flags>{}, str);
+    return opt != old;
 }
 
 template<typename P, typename T>
@@ -348,6 +404,12 @@ inline bool option_add_from_strings(PrefixedList<P, T>& opt, ConstArrayView<Stri
     return option_add_from_strings(opt.list, str);
 }
 
+template<typename P, typename T>
+inline bool option_remove_from_strings(PrefixedList<P, T>& opt, ConstArrayView<String> str)
+{
+    return option_remove_from_strings(opt.list, str);
+}
+
 }
 
 #endif // option_types_hh_INCLUDED