initial commit

preferred_props.go

@@ -0,0 +1,53 @@
+package logic
+
+import (
+	"strings"
+
+	"git.tordarus.net/tordarus/gmath"
+	"git.tordarus.net/tordarus/slices"
+)
+
+// ParsePreferredProps parses properties and its corresponding priority.
+// priorities are distributed exponentially in reverse order.
+//
+// That means the last entry will have priority 1, the second last 2, then 4, 8 and so on.
+//
+// Properties with name "_" will be ignored and function as a placeholder to increase the priority
+// of the properties which comes before them.
+//
+// Properties separated by comma will have the same priorities.
+//
+// str usually is the return value of a call to strings.Split(str, "|")
+//
+// Examples:
+// str = "a|b|c"       -> c:1 b:2 a:4
+// str = "a|b|_|c"     -> c:1 b:4 a:8
+// str = "a,b|c"       -> c:1 b:4 a:4
+// str = "d|_|a,b|c"   -> c:1 b:4 a:4 d:16
+//
+// Additionally, properties can be converted to a generic type with the converter function
+func ParsePreferredProps[T comparable](str []string, converter func(string) (T, error)) map[T]int {
+	props := map[T]int{}
+
+	for i, subProps := range slices.Reverse(str) {
+		if subProps == "_" {
+			continue
+		}
+
+		propPriority := gmath.Pow(2, i)
+		for _, subProp := range strings.Split(subProps, ",") {
+			subPropT, err := converter(subProp)
+			if err != nil {
+				continue
+			}
+
+			props[subPropT] = propPriority
+		}
+	}
+
+	return props
+}
+
+func ParsePreferredStringProps(str []string) map[string]int {
+	return ParsePreferredProps(str, func(s string) (string, error) { return s, nil })
+}