Implement conditions on tag

A condition is formed by:
    <tag> <op> <value>

<tag> is the normal yambar tag. <op> is one of '==', '!=', '<', '<=', '>', or
'>='. <value> is what you wish to compare it to.

'boolean' tags must be used directly. They falsehood is matched with '~':

    <tag>
    ~<tag>

Finally, to match an empty string, one must use ' "" ':
    <tag> <op> ""

doc/yambar-modules-foreign-toplevel.5.scd

@@ -67,10 +67,9 @@ bar:
     - foreign-toplevel:
         content:
           map:
-            tag: activated
-            values:
-              false: {empty: {}}
-              true:
+            conditions:
+              (activated == false): {empty: {}}
+              (activated == true):
                 - string: {text: "{app-id}: {title}"}
 ```
 

doc/yambar-modules-i3.5.scd

@@ -102,10 +102,9 @@ bar:
         content:
           "":
             map:
-              tag: state
               default: {string: {text: "{name}"}}
-              values:
-                focused: {string: {text: "{name}*"}}
+              conditions:
+                (state == focused): {string: {text: "{name}*"}}
           current: { string: {text: "{application}: {title}"}}
 ```
 

doc/yambar-modules-removables.5.scd

@@ -74,13 +74,12 @@ bar:
     - removables:
         content:
           map:
-            tag: mounted
-            values:
-              false:
+            conditions:
+              (mounted == false):
                 string:
                   on-click: udisksctl mount -b {device}
                   text: "{label}"
-              true:
+              (mounted == true):
                 string:
                   on-click: udisksctl unmount -b {device}
                   text: "{label}"

doc/yambar-modules-river.5.scd

@@ -79,10 +79,9 @@ bar:
         title: {string: { text: "{seat} - {title}" }}
         content:
           map:
-            tag: occupied
-            values:
-              false: {empty: {}}
-              true:
+            conditions:
+              (occupied == false): {empty: {}}
+              (occupied == true):
                 string:
                   margin: 5
                   text: "{id}: {state}"

doc/yambar-modules-script.5.scd

@@ -133,10 +133,9 @@ bar:
             title|string|{{title}}
         content:
           map:
-            tag: status
-            values:
-              Paused: {empty: {}}
-              Playing:
+            conditions:
+              (status == Paused): {empty: {}}
+              (status == Playing):
                 content: {string: {text: "{artist} - {title}"}}
 ```
 

doc/yambar-modules.5.scd

@@ -68,20 +68,17 @@ in red.
 ```
 content:
   map:
-    tag: carrier
-    values:
-      false: {empty: {}}
-      true:
+    conditions:
+      (carrier == false): {empty: {}}
+      (carrier == true):
         map:
-          tag: state
           default: {string: {text: , font: *awesome, foreground: ffffff66}}
-          values:
-            up:
+          conditions:
+            (state == up):
               map:
-                tag: ipv4
                 default: {string: {text: , font: *awesome}}
-                values:
-                  "": {string: {text: , font: *awesome, foreground: ffffff66}}
+                conditions:
+                  (ipv4 == ""): {string: {text: , font: *awesome, foreground: ffffff66}}
 ```
 
 ## Use yaml anchors

doc/yambar-particles.5.scd

@@ -208,7 +208,37 @@ content:
 # MAP
 
 This particle maps the values of a specific tag to different
-particles. In addition to explicit tag values, you can also specify a
+particles based on conditions. A condition takes the form of:
+
+<tag> <operation> <value>
+
+Where <tag> is the tag you would like to map, <operation> is one of:
+
+[-  ==
+:- !=
+:- >=
+:- >
+:- <=
+:- <
+
+and <value> is the value you would like to compare it to. Conditions
+may be chained together using either '&&' or '||':
+
+<condition1> && <condition2>
+
+You may surround the *whole expression* with parenthesis to make it
+more readable:
+
+(<condition1> && <condition2>)
+
+Note that "nested" conditions are *NOT* supported. That is, something
+like (<condition1> && (<condition2> || <condition3>)) will *NOT* work.
+
+Furthermore, *conditions are evaluated with a strcmp*. This means
+some odd behaviour may arise if prefixes (such as zeroes) are added
+to numerical constants.
+
+In addition to explicit tag values, you can also specify a
 default/fallback particle.
 
 ## CONFIGURATION
@@ -217,34 +247,29 @@ default/fallback particle.
 :[ *Type*
 :[ *Req*
 :[ *Description*
-|  tag
-:  string
-:  yes
-:  The tag (name of) which values should be mapped
-|  values
+|  conditions
 :  associative array
 :  yes
-:  An associative array of tag values mapped to particles
+:  An associative array  of conditions (see above) mapped to particles
 |  default
 :  particle
 :  no
-:  Default particle to use, when tag's value does not match any of the
-   mapped values.
+:  Default particle to use, none of the conditions are true
 
 ## EXAMPLES
 
 ```
 content:
   map:
-    tag: tag_name
     default:
       string:
         text: this is the default particle; the tag's value is now {tag_name}
-    values:
-      one_value:
+	# Note, below, how the parenthesis are optional
+    conditions:
+      (tag == one_value):
         string:
           text: tag's value is now one_value
-      another_value:
+      tag == another_value:
         string:
           text: tag's value is now another_value