dev

Author: Andrew-M-C

utils/calc/calc.go

@@ -0,0 +1,68 @@
+// Package calc provides some utility functions for calculation.
+//
+// Calc 包提供一些计算相关的工具函数。
+package calc
+
+import (
+	"fmt"
+
+	jsonvalue "github.com/Andrew-M-C/go.jsonvalue"
+)
+
+var emptyValue = &jsonvalue.V{}
+
+// ConcatStrings finds every string-typed sub value of a and b, and concatenates them into a new JSON value.
+//
+// ConcatStrings 找到 a 和 b 的所有 string 类型的子值，并将它们拼接成一个新的 JSON 值。
+func ConcatStrings(a, b *jsonvalue.V) (*jsonvalue.V, error) {
+	if a.ValueType() != b.ValueType() {
+		return emptyValue, fmt.Errorf("%w: input parameters have different types", jsonvalue.ErrParameterError)
+	}
+
+	var res *jsonvalue.V
+
+	switch a.ValueType() {
+	case jsonvalue.String:
+		// for string type, simply concatenate them
+		return jsonvalue.NewString(a.String() + b.String()), nil
+
+	case jsonvalue.Object:
+		// for object type, iterate and concatenate each string-typed sub value
+		res = jsonvalue.NewObject()
+		// and go on
+
+	case jsonvalue.Array:
+		// for array type, iterate and concatenate each string-typed sub value
+		res = jsonvalue.NewArray()
+		// and go on
+
+	default:
+		return emptyValue, fmt.Errorf(
+			"%w: only string, object and array type are supported", jsonvalue.ErrParameterError,
+		)
+	}
+
+	// Walk a
+	a.Walk(func(path jsonvalue.Path, v *jsonvalue.V) bool {
+		// if not string type, simply set it
+		if v.ValueType() != jsonvalue.String {
+			res.MustSet(v).At(path)
+			return true
+		}
+
+		// if string type, just concatenate if
+		strB := b.MustGet(path).String()
+		res.MustSet(v.String() + strB).At(path)
+		return true
+	})
+
+	// Walk b
+	b.Walk(func(path jsonvalue.Path, v *jsonvalue.V) bool {
+		if _, err := res.Get(path); err != nil {
+			res.MustSet(v).At(path) // value not exists, set it
+		}
+		return true
+	})
+
+	return res, nil
+}