Some util functions to support bpfix
Change-Id: If53f696fbe937e007b902434f62d0d92435846dd
diff --git a/parser/ast.go b/parser/ast.go
index 19a79d7..52462f7 100644
--- a/parser/ast.go
+++ b/parser/ast.go
@@ -122,6 +122,40 @@
Eval() Expression
}
+// ExpressionsAreSame tells whether the two values are the same Expression.
+// This includes the symbolic representation of each Expression but not their positions in the original source tree.
+// This does not apply any simplification to the expressions before comparing them
+// (for example, "!!a" wouldn't be deemed equal to "a")
+func ExpressionsAreSame(a Expression, b Expression) (equal bool, err error) {
+ return hackyExpressionsAreSame(a, b)
+}
+
+// TODO(jeffrygaston) once positions are removed from Expression stucts,
+// remove this function and have callers use reflect.DeepEqual(a, b)
+func hackyExpressionsAreSame(a Expression, b Expression) (equal bool, err error) {
+ if a.Type() != b.Type() {
+ return false, nil
+ }
+ left, err := hackyFingerprint(a)
+ if err != nil {
+ return false, nil
+ }
+ right, err := hackyFingerprint(b)
+ if err != nil {
+ return false, nil
+ }
+ areEqual := string(left) == string(right)
+ return areEqual, nil
+}
+
+func hackyFingerprint(expression Expression) (fingerprint []byte, err error) {
+ assignment := &Assignment{"a", noPos, expression, expression, noPos, "=", false}
+ module := &File{}
+ module.Defs = append(module.Defs, assignment)
+ p := newPrinter(module)
+ return p.Print()
+}
+
type Type int
const (
@@ -233,6 +267,31 @@
func (x *Map) Type() Type { return MapType }
+// GetProperty looks for a property with the given name.
+// It resembles the bracket operator of a built-in Golang map.
+func (x *Map) GetProperty(name string) (Property *Property, found bool) {
+ prop, found, _ := x.getPropertyImpl(name)
+ return prop, found // we don't currently expose the index to callers
+}
+
+func (x *Map) getPropertyImpl(name string) (Property *Property, found bool, index int) {
+ for i, prop := range x.Properties {
+ if prop.Name == name {
+ return prop, true, i
+ }
+ }
+ return nil, false, -1
+}
+
+// GetProperty removes the property with the given name, if it exists.
+func (x *Map) RemoveProperty(propertyName string) (removed bool) {
+ _, found, index := x.getPropertyImpl(propertyName)
+ if found {
+ x.Properties = append(x.Properties[:index], x.Properties[index+1:]...)
+ }
+ return found
+}
+
type List struct {
LBracePos scanner.Position
RBracePos scanner.Position
