use plain pkg module

Signed-off-by: Jörn Friedrich Dreyer <jfd@butonic.de>

pkg/ast/ast.go

@@ -0,0 +1,107 @@
+// Package ast provides available ast nodes.
+package ast
+
+import (
+	"time"
+)
+
+// Node represents abstract syntax tree node
+type Node interface {
+	Location() *Location
+}
+
+// Position represents a specific location in the source
+type Position struct {
+	Line   int
+	Column int
+}
+
+// Location represents the location of a node in the AST
+type Location struct {
+	Start  Position `json:"start"`
+	End    Position `json:"end"`
+	Source *string  `json:"source,omitempty"`
+}
+
+// Base contains shared node attributes
+// each node should inherit from this
+type Base struct {
+	Loc *Location
+}
+
+// Location is the source location of the Node
+func (b *Base) Location() *Location { return b.Loc }
+
+// Ast represents the query - node structure as abstract syntax tree
+type Ast struct {
+	*Base
+	Nodes []Node `json:"body"`
+}
+
+// StringNode represents a string value
+type StringNode struct {
+	*Base
+	Key   string
+	Value string
+}
+
+// BooleanNode represents a bool value
+type BooleanNode struct {
+	*Base
+	Key   string
+	Value bool
+}
+
+// DateTimeNode represents a time.Time value
+type DateTimeNode struct {
+	*Base
+	Key      string
+	Operator *OperatorNode
+	Value    time.Time
+}
+
+// OperatorNode represents an operator value like
+// AND, OR, NOT, =, <= ... and so on
+type OperatorNode struct {
+	*Base
+	Value string
+}
+
+// GroupNode represents a collection of many grouped nodes
+type GroupNode struct {
+	*Base
+	Key   string
+	Nodes []Node
+}
+
+// NodeKey tries to return the node key
+func NodeKey(n Node) string {
+	switch node := n.(type) {
+	case *StringNode:
+		return node.Key
+	case *DateTimeNode:
+		return node.Key
+	case *BooleanNode:
+		return node.Key
+	case *GroupNode:
+		return node.Key
+	default:
+		return ""
+	}
+}
+
+// NodeValue tries to return the node key
+func NodeValue(n Node) interface{} {
+	switch node := n.(type) {
+	case *StringNode:
+		return node.Value
+	case *DateTimeNode:
+		return node.Value
+	case *BooleanNode:
+		return node.Value
+	case *GroupNode:
+		return node.Nodes
+	default:
+		return ""
+	}
+}

pkg/ast/test/test.go

@@ -0,0 +1,26 @@
+// Package test provides shared test primitives for ast testing.
+package test
+
+import (
+	"github.com/google/go-cmp/cmp"
+	"github.com/google/go-cmp/cmp/cmpopts"
+	"github.com/opencloud-eu/opencloud/pkg/ast"
+)
+
+// DiffAst returns a human-readable report of the differences between two values
+// by default it ignores every ast node Base field.
+func DiffAst(x, y interface{}, opts ...cmp.Option) string {
+	return cmp.Diff(
+		x,
+		y,
+		append(
+			opts,
+			cmpopts.IgnoreFields(ast.Ast{}, "Base"),
+			cmpopts.IgnoreFields(ast.StringNode{}, "Base"),
+			cmpopts.IgnoreFields(ast.OperatorNode{}, "Base"),
+			cmpopts.IgnoreFields(ast.GroupNode{}, "Base"),
+			cmpopts.IgnoreFields(ast.BooleanNode{}, "Base"),
+			cmpopts.IgnoreFields(ast.DateTimeNode{}, "Base"),
+		)...,
+	)
+}