matcher: Add a `greater` and `lesser` matching sections.

In a perfect world we would have pure expression matching, but
that's problematic with all the "metaness" of the code. For now,
this adds an imperfect way to match the minimum and maximum of
number properties.

It will be used by the screen rules for the DPI and size properties.

lib/gears/matcher.lua

@@ -76,41 +76,47 @@ local matcher = {}
 -- @tparam table gears.matcher The matcher.
 -- @see remove_matching_source
 
+local function default_matcher(a, b)
+    return a == b or (type(a) == "string" and a:match(b))
+end
+
+local function greater_matcher(a, b)
+    return a > b
+end
+
+local function lesser_matcher(a, b)
+    return a < b
+end
+
 -- Check if an object matches a rule.
 -- @param o The object.
 -- #tparam table rule The rule to check.
 -- @treturn boolean True if it matches, false otherwise.
-function matcher:_match(o, rule)
+-- @method _match
+function matcher:_match(o, rule, matcher_f)
     if not rule then return false end
+
+    matcher_f = matcher_f or default_matcher
+
     for field, value in pairs(rule) do
         local pm = self._private.prop_matchers[field]
-        if pm then
-            if not pm(o, value, field) then
-                return false
-            end
-        elseif o[field] ~= nil then
-            if type(o[field]) == "string" then
-                if not o[field]:match(value) and o[field] ~= value then
-                    return false
-                end
-            elseif o[field] ~= value then
-                return false
-            end
-        else
+        if pm and pm(o, value, field) then
+            return true
+        elseif not matcher_f(o[field], value) then
             return false
         end
     end
     return true
 end
 
-local function field_matcher(self, o, field, value)
+local function field_matcher(self, o, field, value, matcher_f)
+    matcher_f = matcher_f or default_matcher
+
     local pm = self._private.prop_matchers[field]
 
     if pm and pm(o, value, field) then
         return true
-    elseif o[field] == value then
-        return true
-    elseif type(o[field]) == "string" and o[field]:match(value) then
+    elseif matcher_f(o[field] , value) then
         return true
     end
 
@@ -121,12 +127,21 @@ end
 -- @param o The object.
 -- #tparam table rule The rule _match_anyto check.
 -- @treturn boolean True if at least one rule is matched, false otherwise.
+-- @method _match_any
 function matcher:_match_any(o, rule)
     if not rule then return false end
     for field, values in pairs(rule) do
         if o[field] then
+
+            -- Special case, "all"
+            if type(values) == "boolean" and values then
+                return true
+            end
+
             for _, value in ipairs(values) do
-                if field_matcher(self, o, field, value) then return true end
+                if field_matcher(self, o, field, value) then
+                    return true
+                end
             end
         end
     end
@@ -140,6 +155,7 @@ end
 -- @tparam table rule The rule _match_anyto check.
 -- @tparam boolean multi If the entries are table of choices.
 -- @treturn boolean True if all rules are matched.
+-- @method _match_every
 function matcher:_match_every(o, rule)
     if not rule then return true end
 
@@ -168,10 +184,26 @@ end
 -- @method matches_rule
 function matcher:matches_rule(o, entry)
     local match = self:_match(o, entry.rule) or self:_match_any(o, entry.rule_any)
-    return match
-        and self:_match_every     (o, entry.rule_every)
-        and (not self:_match      (o, entry.except    ))
-        and (not self:_match_any  (o, entry.except_any))
+
+    -- If there was `rule` or `rule_any` and they failed to match, look no further.
+    if (not match) and (entry.rule or entry.rule_any) then return false end
+
+    if not self:_match_every(o, entry.rule_every) then return false end
+
+    -- Negative matching.
+    if entry.except and self:_match(o, entry.except) then return false end
+    if entry.except_any and self:_match_any(o, entry.except_any) then return false end
+
+    -- Other operators.
+    if entry.rule_greater and not self:_match(o, entry.rule_greater, greater_matcher) then
+        return false
+    end
+
+    if entry.rule_lesser and not self:_match(o, entry.rule_lesser, lesser_matcher) then
+        return false
+    end
+
+    return true
 end
 
 --- Get list of matching rules for an object.