[Themes] add calc() support to distance in theme format. (#1105)

* Initial test to allow math in distances.

Support + and -
Needs spaces around + and -.

* [THEME] Fix printing theme with math in distance.

* [Theme] use calc() syntax.

* [Theme] Add * and /  to calc().

* [Theme] Fix the precedense ordering in parsing. Also avoid making copies.

* [Theme] Don't print unneeded ().

* [Theme] Add modulo to calc.

2 files changed, 29 insertions, 1 deletions

diff --git a/include/rofi-types.h b/include/rofi-types.h
index bb294dad..ced7e321 100644
--- a/include/rofi-types.h
+++ b/include/rofi-types.h
@@ -89,12 +89,39 @@ typedef enum
 /**
  * Structure representing a distance.
  */
-typedef struct
+typedef enum
+{
+    ROFI_DISTANCE_MODIFIER_NONE,
+    ROFI_DISTANCE_MODIFIER_ADD,
+    ROFI_DISTANCE_MODIFIER_SUBTRACT,
+    ROFI_DISTANCE_MODIFIER_DIVIDE,
+    ROFI_DISTANCE_MODIFIER_MULTIPLY,
+    ROFI_DISTANCE_MODIFIER_MODULO,
+    ROFI_DISTANCE_MODIFIER_GROUP,
+} RofiDistanceModifier;
+
+typedef struct RofiDistanceUnit 
 {
     /** Distance */
     double        distance;
     /** Unit type of the distance */
     RofiPixelUnit type;
+
+    /** Type */
+    RofiDistanceModifier modtype;
+
+    /** Modifier */
+    struct RofiDistanceUnit *left;
+
+    /** Modifier */
+    struct RofiDistanceUnit *right;
+
+} RofiDistanceUnit;
+
+typedef struct
+{
+    /** Base */
+    RofiDistanceUnit base;
     /** Style of the line (optional)*/
     RofiLineStyle style;
 } RofiDistance;
diff --git a/include/theme.h b/include/theme.h
index 0ed71460..055bea71 100644
--- a/include/theme.h
+++ b/include/theme.h
@@ -387,4 +387,5 @@ void rofi_theme_parse_merge_widgets ( ThemeWidget *parent, ThemeWidget *child );
  * Returns the media type described by type.
  */
 ThemeMediaType rofi_theme_parse_media_type ( const char *type );
+RofiDistance rofi_theme_property_copy_distance  ( RofiDistance const distance );
 #endif