add arango package with aql generation

query.go

@@ -0,0 +1,87 @@
+package arango
+
+import (
+	"strings"
+)
+
+// Query provides a simple way to build ArangoDB queries.
+type Query struct {
+	Lines  []string
+	Params map[string]any
+}
+
+// Append adds a line to the query, attaching (optional) values to bind parameters.
+//
+// Any variables given are assigned to bind parameters in the same order as they appear in the line.
+// Keep in mind the following behaviours:
+//
+//   - If more variables are provided than there are parameters in the line, leftover variables are discarded
+//   - If more parameters are used than variables are given, remaining parameters are left unmapped
+//   - Reused parameters are overwritten
+func (query *Query) Append(line string, values ...any) *Query {
+	var params map[string]any = nil
+
+	names := ReadParams(line)
+	if len(names) > 0 {
+		params = map[string]any{}
+		for i, name := range names {
+			if i > len(values) {
+				break
+			}
+			params[name] = values[i]
+		}
+	}
+
+	query.Lines = append(query.Lines, line)
+	return query.AssignMap(params)
+}
+
+// Assign assigns a value to a single bind parameter.
+func (query *Query) Assign(name string, value any) *Query {
+	query.Params[name] = value
+	return query
+}
+
+// AssignMap assigns values to bind parameters.
+func (query *Query) AssignMap(params map[string]any) *Query {
+	if params != nil {
+		for name, value := range params {
+			query.Params[name] = value
+		}
+	}
+	return query
+}
+
+// Copy creates a copy of the query.
+func (query *Query) Copy() *Query {
+	newQuery := NewQuery()
+	for _, line := range query.Lines {
+		newQuery.Lines = append(newQuery.Lines, line)
+	}
+	for name, value := range query.Params {
+		newQuery.Params[name] = value
+	}
+	return newQuery
+}
+
+// L (for "Line") is a shorthand for Append.
+func (query *Query) L(line string, values ...any) *Query {
+	return query.Append(line, values...)
+}
+
+// P (for "Parameter") is a shorthand for Assign.
+func (query *Query) P(name string, value any) *Query {
+	return query.Assign(name, value)
+}
+
+func (query *Query) String() string {
+	return strings.Join(query.Lines, "\n")
+}
+
+// NewQuery creates a new Query.
+func NewQuery() *Query {
+	return &Query{
+		Lines:  []string{},
+		Params: map[string]any{},
+	}
+}