1 files changed, 51 insertions, 0 deletions
diff --git a/go/game/effect.go b/go/game/effect.go
index 1fd2a630..4d89eea5 100644
--- a/go/game/effect.go
+++ b/go/game/effect.go
@@ -1,5 +1,11 @@
 package game
 
+import (
+	"errors"
+	"regexp"
+	"strconv"
+)
+
 type effect interface {
 	apply(*LocalState)
 	end(*LocalState)
@@ -45,3 +51,48 @@ func newTmpEffect(p Permanent, effect string) effect {
 	end := func(*LocalState) { p.removeTmpEffect(effect) }
 	return &dynamicEffect{apply, end}
 }
+
+type xEffect struct {
+	// amount of the effect
+	x int
+	// does the effect set or adjust the value
+	set bool
+	// raw effect description
+	raw string
+}
+
+type ErrXEffectError struct {
+	err error
+}
+
+func (e ErrXEffectError) Error() string {
+	return e.err.Error()
+}
+
+var ErrXEffectFormat = ErrXEffectError{errors.New("invalid format")}
+
+var (
+	xEffectXSuffix = regexp.MustCompile(`\S+ ([\+-]?)(\d+)`)
+	xEffectXPrefix = regexp.MustCompile(`([\+-]?)(\d+) \S+`)
+)
+
+func parseXEffect(desc string) (e xEffect, err error) {
+	e.raw = desc
+	m := xEffectXSuffix.FindAllStringSubmatch(desc, -1)
+	if len(m) == 0 {
+		m = xEffectXPrefix.FindAllStringSubmatch(desc, -1)
+	}
+
+	if len(m) != 0 {
+		e.set = m[0][1] == ""
+
+		e.x, err = strconv.Atoi(m[0][1] + m[0][2])
+		if err != nil {
+			return e, ErrXEffectError{err}
+		}
+		return e, nil
+	}
+
+	// Both regex did not match
+	return e, ErrXEffectFormat
+}