Allow parsing Blueprints files without evaluating
Running bpfmt or bpmodify on a Blueprints file that references
variables defined in a parent Blueprints file causes parse errors
on unknown variables. Modify the parser to parse in two modes,
parser.Parse and parser.ParseAndEval. The first parses without
attempting to evaluate variables and expressions, the second
performs a full evaluation.
Change-Id: Ic11948ea77c8e65379d7260591ada15db0e4f5b9
diff --git a/context.go b/context.go
index 0e0a38e..4437ded 100644
--- a/context.go
+++ b/context.go
@@ -430,7 +430,7 @@
scope = parser.NewScope(scope)
scope.Remove("subdirs")
- file, errs := parser.Parse(filename, r, scope)
+ file, errs := parser.ParseAndEval(filename, r, scope)
if len(errs) > 0 {
for i, err := range errs {
if parseErr, ok := err.(*parser.ParseError); ok {
diff --git a/parser/parser.go b/parser/parser.go
index 9366283..498bdcb 100644
--- a/parser/parser.go
+++ b/parser/parser.go
@@ -42,11 +42,7 @@
Comments []Comment
}
-func Parse(filename string, r io.Reader, scope *Scope) (file *File, errs []error) {
-
- p := newParser(r, scope)
- p.scanner.Filename = filename
-
+func parse(p *parser) (file *File, errs []error) {
defer func() {
if r := recover(); r != nil {
if r == errTooManyErrors {
@@ -66,30 +62,42 @@
Defs: defs,
Comments: comments,
}, errs
+
+}
+
+func ParseAndEval(filename string, r io.Reader, scope *Scope) (file *File, errs []error) {
+ p := newParser(r, scope)
+ p.eval = true
+ p.scanner.Filename = filename
+
+ return parse(p)
+}
+
+func Parse(filename string, r io.Reader, scope *Scope) (file *File, errs []error) {
+ p := newParser(r, scope)
+ p.scanner.Filename = filename
+
+ return parse(p)
}
type parser struct {
- scanner scanner.Scanner
- tok rune
- errors []error
- scope *Scope
- parseComments bool
- comments []Comment
+ scanner scanner.Scanner
+ tok rune
+ errors []error
+ scope *Scope
+ comments []Comment
+ eval bool
}
func newParser(r io.Reader, scope *Scope) *parser {
p := &parser{}
p.scope = scope
- p.parseComments = true
p.scanner.Init(r)
p.scanner.Error = func(sc *scanner.Scanner, msg string) {
p.errorf(msg)
}
p.scanner.Mode = scanner.ScanIdents | scanner.ScanStrings |
scanner.ScanRawStrings | scanner.ScanComments
- if !p.parseComments {
- p.scanner.Mode |= scanner.SkipComments
- }
p.next()
return p
}
@@ -183,13 +191,19 @@
if p.scope != nil {
if assigner == "+=" {
- p.scope.Append(assignment)
- } else {
- err := p.scope.Add(assignment)
- if err != nil {
- p.errorf("%s", err.Error())
+ if old, err := p.scope.Get(assignment.Name.Name); err == nil {
+ if old.Referenced {
+ p.errorf("modified variable with += after referencing")
+ }
+ old.Value, err = p.evaluateOperator(old.Value, assignment.Value, '+', assignment.Pos)
+ return
}
}
+
+ err := p.scope.Add(assignment)
+ if err != nil {
+ p.errorf("%s", err.Error())
+ }
}
return
@@ -280,35 +294,41 @@
}
}
-func evaluateOperator(value1, value2 Value, operator rune, pos scanner.Position) (Value, error) {
- if value1.Type != value2.Type {
- return Value{}, fmt.Errorf("mismatched type in operator %c: %s != %s", operator,
- value1.Type, value2.Type)
- }
+func (p *parser) evaluateOperator(value1, value2 Value, operator rune,
+ pos scanner.Position) (Value, error) {
- value := value1
- value.Variable = ""
+ value := Value{}
- switch operator {
- case '+':
- switch value1.Type {
- case String:
- value.StringValue = value1.StringValue + value2.StringValue
- case List:
- value.ListValue = append([]Value{}, value1.ListValue...)
- value.ListValue = append(value.ListValue, value2.ListValue...)
- case Map:
- var err error
- value.MapValue, err = addMaps(value.MapValue, value2.MapValue, pos)
- if err != nil {
- return Value{}, err
+ if p.eval {
+ if value1.Type != value2.Type {
+ return Value{}, fmt.Errorf("mismatched type in operator %c: %s != %s", operator,
+ value1.Type, value2.Type)
+ }
+
+ value = value1
+ value.Variable = ""
+
+ switch operator {
+ case '+':
+ switch value1.Type {
+ case String:
+ value.StringValue = value1.StringValue + value2.StringValue
+ case List:
+ value.ListValue = append([]Value{}, value1.ListValue...)
+ value.ListValue = append(value.ListValue, value2.ListValue...)
+ case Map:
+ var err error
+ value.MapValue, err = p.addMaps(value.MapValue, value2.MapValue, pos)
+ if err != nil {
+ return Value{}, err
+ }
+ default:
+ return Value{}, fmt.Errorf("operator %c not supported on type %s", operator,
+ value1.Type)
}
default:
- return Value{}, fmt.Errorf("operator %c not supported on type %s", operator,
- value1.Type)
+ panic("unknown operator " + string(operator))
}
- default:
- panic("unknown operator " + string(operator))
}
value.Expression = &Expression{
@@ -320,7 +340,7 @@
return value, nil
}
-func addMaps(map1, map2 []*Property, pos scanner.Position) ([]*Property, error) {
+func (p *parser) addMaps(map1, map2 []*Property, pos scanner.Position) ([]*Property, error) {
ret := make([]*Property, 0, len(map1))
inMap1 := make(map[string]*Property)
@@ -342,7 +362,7 @@
if prop2, ok := inBoth[prop1.Name.Name]; ok {
var err error
newProp := *prop1
- newProp.Value, err = evaluateOperator(prop1.Value, prop2.Value, '+', pos)
+ newProp.Value, err = p.evaluateOperator(prop1.Value, prop2.Value, '+', pos)
if err != nil {
return nil, err
}
@@ -368,7 +388,7 @@
value2 := p.parseExpression()
- value, err := evaluateOperator(value1, value2, operator, pos)
+ value, err := p.evaluateOperator(value1, value2, operator, pos)
if err != nil {
p.errorf(err.Error())
return Value{}
@@ -404,11 +424,14 @@
value.BoolValue = false
default:
variable := p.scanner.TokenText()
- assignment, err := p.scope.Get(variable)
- if err != nil {
- p.errorf(err.Error())
+ if p.eval {
+ assignment, err := p.scope.Get(variable)
+ if err != nil {
+ p.errorf(err.Error())
+ }
+ assignment.Referenced = true
+ value = assignment.Value
}
- value = assignment.Value
value.Variable = variable
}
value.Pos = p.scanner.Position
@@ -440,7 +463,7 @@
var elements []Value
for p.tok != ']' {
element := p.parseExpression()
- if element.Type != String {
+ if p.eval && element.Type != String {
p.errorf("Expected string in list, found %s", element.String())
return
}
@@ -644,27 +667,12 @@
return nil
}
-func (s *Scope) Append(assignment *Assignment) error {
- var err error
- if old, ok := s.vars[assignment.Name.Name]; ok {
- if old.Referenced {
- return fmt.Errorf("modified variable with += after referencing")
- }
- old.Value, err = evaluateOperator(old.Value, assignment.Value, '+', assignment.Pos)
- } else {
- err = s.Add(assignment)
- }
-
- return err
-}
-
func (s *Scope) Remove(name string) {
delete(s.vars, name)
}
func (s *Scope) Get(name string) (*Assignment, error) {
if a, ok := s.vars[name]; ok {
- a.Referenced = true
return a, nil
}
diff --git a/parser/parser_test.go b/parser/parser_test.go
index 4c4acab..8925684 100644
--- a/parser/parser_test.go
+++ b/parser/parser_test.go
@@ -477,7 +477,7 @@
func TestParseValidInput(t *testing.T) {
for _, testCase := range validParseTestCases {
r := bytes.NewBufferString(testCase.input)
- file, errs := Parse("", r, NewScope(nil))
+ file, errs := ParseAndEval("", r, NewScope(nil))
if len(errs) != 0 {
t.Errorf("test case: %s", testCase.input)
t.Errorf("unexpected errors:")
