[Calc] Add min/max operator support to calc()

Fixes: #1172

doc/rofi-theme.5.markdown

@@ -364,11 +364,13 @@ width: calc( 100% - 37px );
 
 It supports the following operations:
 
-* `+`: Add
+* `+`   : Add
-* `-`: Subtract
+* `-`   : Subtract
-* `/`: Divide
+* `/`   : Divide
-* `*`: Multiply
+* `*`   : Multiply
-* `%`: Multiply
+* `%`   : Multiply
+* `min` : Minimum of l or rvalue;
+* `max` : Maximum of l or rvalue;
 
 It uses the C precedence ordering.
 

include/rofi-types.h

@@ -102,6 +102,8 @@ typedef enum
     ROFI_DISTANCE_MODIFIER_MULTIPLY,
     ROFI_DISTANCE_MODIFIER_MODULO,
     ROFI_DISTANCE_MODIFIER_GROUP,
+    ROFI_DISTANCE_MODIFIER_MIN,
+    ROFI_DISTANCE_MODIFIER_MAX,
 } RofiDistanceModifier;
 
 typedef struct RofiDistanceUnit

lexer/theme-lexer.l

@@ -189,6 +189,8 @@ ENV        $\{[[:alnum:]]*\}
 MODIFIER_ADD      \+
 MODIFIER_SUBTRACT -
 MODIFIER_MULTIPLY \*
+MODIFIER_MIN      (min)
+MODIFIER_MAX      (max)
 
  /* Position */
 CENTER     (?i:center)
@@ -463,6 +465,8 @@ if ( queue == NULL ){
 <PROPERTIES,PROPERTIES_ENV,PROPERTIES_VAR_DEFAULT>{MODIFIER_ADD}       { return T_MODIFIER_ADD; }
 <PROPERTIES,PROPERTIES_ENV,PROPERTIES_VAR_DEFAULT>{MODIFIER_SUBTRACT}  { return T_MODIFIER_SUBTRACT; }
 <PROPERTIES,PROPERTIES_ENV,PROPERTIES_VAR_DEFAULT>{MODIFIER_MULTIPLY}  { return T_MODIFIER_MULTIPLY; }
+<PROPERTIES,PROPERTIES_ENV,PROPERTIES_VAR_DEFAULT>{MODIFIER_MIN}  { return T_MODIFIER_MIN; }
+<PROPERTIES,PROPERTIES_ENV,PROPERTIES_VAR_DEFAULT>{MODIFIER_MAX}  { return T_MODIFIER_MAX; }
 <PROPERTIES,PROPERTIES_ENV,PROPERTIES_VAR_DEFAULT>{CALC}  { return T_CALC; }
 
 <PROPERTIES,PROPERTIES_ENV,PROPERTIES_VAR_DEFAULT>{ENV} {

lexer/theme-parser.y

@@ -218,6 +218,9 @@ static ThemeColor hwb_to_rgb ( double h, double w, double b)
 %token T_MODIFIER_SUBTRACT              "Subtract ('-')"
 %token T_MODIFIER_MULTIPLY              "Multiply ('*')"
 
+%token T_MODIFIER_MAX                   "Max ('max')"
+%token T_MODIFIER_MIN                   "Min ('min')"
+
 %token T_CALC                           "calc"
 
 %token T_BOPEN                          "bracket open ('{')"
@@ -261,6 +264,7 @@ static ThemeColor hwb_to_rgb ( double h, double w, double b)
 %type <distance>       t_property_distance_zero
 %type <distance_unit>  t_property_distance_unit_math
 %type <distance_unit>  t_property_distance_unit_math2
+%type <distance_unit>  t_property_distance_unit_math3
 %type <distance_unit>  t_property_distance_unit
 %type <ival>           t_property_unit
 %type <wloc>           t_property_position
@@ -601,7 +605,7 @@ t_property_distance_unit
     $$->right    = NULL;
     $$->modtype = ROFI_DISTANCE_MODIFIER_NONE;
 }
-| T_PARENT_LEFT t_property_distance_unit_math2 T_PARENT_RIGHT {
+| T_PARENT_LEFT t_property_distance_unit_math3 T_PARENT_RIGHT {
     $$ = g_slice_new0(RofiDistanceUnit);
     $$->distance = 0;
     $$->type     = ROFI_PU_PX;
@@ -655,6 +659,23 @@ t_property_distance_unit_math2
 | t_property_distance_unit_math  {
     $$ = $1;
 };
+/** Level 3  (min max)*/
+t_property_distance_unit_math3
+: t_property_distance_unit_math3 T_MODIFIER_MIN t_property_distance_unit_math2 {
+    $$ = g_slice_new0(RofiDistanceUnit);
+    $$->left = $1;
+    $$->right = $3;
+    $$->modtype = ROFI_DISTANCE_MODIFIER_MIN;
+}
+| t_property_distance_unit_math3 T_MODIFIER_MAX t_property_distance_unit_math2 {
+    $$ = g_slice_new0(RofiDistanceUnit);
+    $$->left = $1;
+    $$->right = $3;
+    $$->modtype = ROFI_DISTANCE_MODIFIER_MAX;
+}
+| t_property_distance_unit_math2  {
+    $$ = $1;
+};
 
 
 t_property_distance
@@ -676,7 +697,7 @@ t_property_distance
     $$.base.right = NULL;
     $$.style    = $3;
 }
-| T_CALC T_PARENT_LEFT t_property_distance_unit_math2 T_PARENT_RIGHT t_property_line_style {
+| T_CALC T_PARENT_LEFT t_property_distance_unit_math3 T_PARENT_RIGHT t_property_line_style {
     $$.base.distance = 0;
     $$.base.type     = ROFI_PU_PX;
     $$.base.left = $3;

source/theme.c

@@ -297,6 +297,12 @@ static void rofi_theme_print_distance_unit ( RofiDistanceUnit *unit )
     else if ( unit->modtype == ROFI_DISTANCE_MODIFIER_MODULO ) {
         fputs ( " % ", stdout );
     }
+    else if ( unit->modtype == ROFI_DISTANCE_MODIFIER_MIN ) {
+        fputs ( " min ", stdout );
+    }
+    else if ( unit->modtype == ROFI_DISTANCE_MODIFIER_MAX ) {
+        fputs ( " max ", stdout );
+    }
     if ( unit->right ) {
         rofi_theme_print_distance_unit ( unit->right );
     }
@@ -998,6 +1004,18 @@ static int distance_unit_get_pixel ( RofiDistanceUnit *unit, RofiOrientation ori
         }
         return 0;
     }
+    case ROFI_DISTANCE_MODIFIER_MIN:
+    {
+        int a = distance_unit_get_pixel ( unit->left, ori );
+        int b = distance_unit_get_pixel ( unit->right, ori );
+        return MIN(a,b);
+    }
+    case ROFI_DISTANCE_MODIFIER_MAX:
+    {
+        int a = distance_unit_get_pixel ( unit->left, ori );
+        int b = distance_unit_get_pixel ( unit->right, ori );
+        return MAX(a,b);
+    }
     default:
         break;
     }