67 lines
1.3 KiB
Go
67 lines
1.3 KiB
Go
|
package main
|
||
|
|
|
||
|
|
//-------------------------------------------------------------------------
|
||
|
|
// scope
|
||
|
|
//-------------------------------------------------------------------------
|
||
|
|
|
||
|
|
type scope struct {
|
||
|
|
parent *scope // nil for universe scope
|
||
|
|
entities map[string]*decl
|
||
|
|
}
|
||
|
|
|
||
|
|
func new_scope(outer *scope) *scope {
|
||
|
|
s := new(scope)
|
||
|
|
s.parent = outer
|
||
|
|
s.entities = make(map[string]*decl)
|
||
|
|
return s
|
||
|
|
}
|
||
|
|
|
||
|
|
// returns: new, prev
|
||
|
|
func advance_scope(s *scope) (*scope, *scope) {
|
||
|
|
if len(s.entities) == 0 {
|
||
|
|
return s, s.parent
|
||
|
|
}
|
||
|
|
return new_scope(s), s
|
||
|
|
}
|
||
|
|
|
||
|
|
// adds declaration or returns an existing one
|
||
|
|
func (s *scope) add_named_decl(d *decl) *decl {
|
||
|
|
return s.add_decl(d.name, d)
|
||
|
|
}
|
||
|
|
|
||
|
|
func (s *scope) add_decl(name string, d *decl) *decl {
|
||
|
|
decl, ok := s.entities[name]
|
||
|
|
if !ok {
|
||
|
|
s.entities[name] = d
|
||
|
|
return d
|
||
|
|
}
|
||
|
|
return decl
|
||
|
|
}
|
||
|
|
|
||
|
|
func (s *scope) replace_decl(name string, d *decl) {
|
||
|
|
s.entities[name] = d
|
||
|
|
}
|
||
|
|
|
||
|
|
func (s *scope) merge_decl(d *decl) {
|
||
|
|
decl, ok := s.entities[d.name]
|
||
|
|
if !ok {
|
||
|
|
s.entities[d.name] = d
|
||
|
|
} else {
|
||
|
|
decl := decl.deep_copy()
|
||
|
|
decl.expand_or_replace(d)
|
||
|
|
s.entities[d.name] = decl
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
func (s *scope) lookup(name string) *decl {
|
||
|
|
decl, ok := s.entities[name]
|
||
|
|
if !ok {
|
||
|
|
if s.parent != nil {
|
||
|
|
return s.parent.lookup(name)
|
||
|
|
} else {
|
||
|
|
return nil
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return decl
|
||
|
|
}
|