internal/core/subsume/structural.go - cue - Git at Google

 // Copyright 2020 CUE Authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.

 package subsume

 // TODO: structural subsumption has not yet been implemented.

 import "cuelang.org/go/internal/core/adt"

 func (s *subsumer) subsumes(gt, lt adt.Conjunct) bool {
 	if gt == lt {
 		return true
 	}

 	// First try evaluating at the value level.
 	x, _ := gt.Expr().(adt.Value)
 	y, _ := lt.Expr().(adt.Value)
 	if x == nil {
 		// Fall back to structural.
 		return s.structural(gt, lt)
 	}
 	if y == nil {
 		return false
 	}

 	return s.values(x, y)
 }

 func (s *subsumer) conjunct(gt, lt adt.Conjunct) bool {
 	return false
 }

 func (s *subsumer) c(env *adt.Environment, x adt.Expr) adt.Conjunct {
 	return adt.MakeConjunct(env, x)
 }

 func isBottomConjunct(c adt.Conjunct) bool {
 	b, _ := c.Expr().(*adt.Bottom)
 	return b != nil
 }

 func (s *subsumer) node(env *adt.Environment, up int32) *adt.Vertex {
 	for ; up != 0; up-- {
 		env = env.Up
 	}
 	return env.Vertex
 }

 func (s *subsumer) structural(a, b adt.Conjunct) bool {
 	if y, ok := b.Expr().(*adt.LetReference); ok {
 		return s.conjunct(a, s.c(b.Env, y.X))
 	}
 	if isBottomConjunct(b) {
 		return true
 	}

 	switch x := a.Expr().(type) {
 	case *adt.DisjunctionExpr:

 	case *adt.StructLit:
 	case *adt.ListLit:

 	case *adt.FieldReference:
 		if y, ok := b.Expr().(*adt.FieldReference); ok && x.Label == y.Label {
 			if s.node(a.Env, x.UpCount) == s.node(b.Env, y.UpCount) {
 				return true
 			}
 		}

 	case *adt.LabelReference:
 		if y, ok := b.Expr().(*adt.LabelReference); ok {
 			if s.node(a.Env, x.UpCount) == s.node(b.Env, y.UpCount) {
 				return true
 			}
 		}

 	case *adt.DynamicReference:
 		if y, ok := b.Expr().(*adt.FieldReference); ok {
 			if s.node(a.Env, x.UpCount) == s.node(b.Env, y.UpCount) {
 				return true
 			}
 		}

 	case *adt.ImportReference:
 		if y, ok := b.Expr().(*adt.ImportReference); ok &&
 			x.ImportPath == y.ImportPath {
 			return true
 		}

 	case *adt.LetReference:
 		return s.conjunct(s.c(a.Env, x.X), b)

 	case *adt.SelectorExpr:
 		if y, ok := a.Expr().(*adt.SelectorExpr); ok &&
 			x.Sel == y.Sel &&
 			s.conjunct(s.c(a.Env, x.X), s.c(b.Env, y.X)) {
 			return true
 		}

 	case *adt.IndexExpr:
 		if y, ok := b.Expr().(*adt.IndexExpr); ok &&
 			s.conjunct(s.c(a.Env, x.X), s.c(b.Env, y.X)) &&
 			s.conjunct(s.c(a.Env, x.Index), s.c(b.Env, y.Index)) {
 			return true
 		}

 	case *adt.SliceExpr:
 		if r, ok := b.Expr().(*adt.SliceExpr); ok &&
 			s.conjunct(s.c(a.Env, x.X), s.c(b.Env, r.X)) &&
 			s.conjunct(s.c(a.Env, x.Lo), s.c(b.Env, r.Lo)) &&
 			s.conjunct(s.c(a.Env, x.Hi), s.c(b.Env, r.Hi)) {
 			return true
 		}

 	case *adt.Interpolation:
 		switch y := b.Expr().(type) {
 		case *adt.String:
 			// Be conservative if not ground.
 			s.inexact = true

 		case *adt.Interpolation:
 			// structural equivalence
 			if len(x.Parts) != len(y.Parts) {
 				return false
 			}
 			for i, p := range x.Parts {
 				if !s.conjunct(s.c(a.Env, p), s.c(b.Env, y.Parts[i])) {
 					return false
 				}
 			}
 			return true
 		}

 	case *adt.BoundExpr:
 		if y, ok := b.Expr().(*adt.BoundExpr); ok && x.Op == y.Op {
 			return s.conjunct(s.c(a.Env, x.Expr), s.c(b.Env, y.Expr))
 		}

 	case *adt.UnaryExpr:
 		if y, ok := b.Expr().(*adt.UnaryExpr); ok && x.Op == y.Op {
 			return s.conjunct(s.c(a.Env, x.X), s.c(b.Env, y.X))
 		}

 	case *adt.BinaryExpr:
 		if y, ok := b.Expr().(*adt.BinaryExpr); ok && x.Op == y.Op {
 			return s.conjunct(s.c(a.Env, x.X), s.c(b.Env, y.X)) &&
 				s.conjunct(s.c(a.Env, x.Y), s.c(b.Env, y.Y))
 		}

 	case *adt.CallExpr:
 		if y, ok := b.Expr().(*adt.CallExpr); ok {
 			if len(x.Args) != len(y.Args) {
 				return false
 			}
 			for i, arg := range x.Args {
 				if !s.conjunct(s.c(a.Env, arg), s.c(b.Env, y.Args[i])) {
 					return false
 				}
 			}
 			return s.conjunct(s.c(a.Env, x.Fun), s.c(b.Env, y.Fun))
 		}
 	}
 	return false
 }

 func (s *subsumer) structLit(
 	ea *adt.Environment, sa *adt.StructLit,
 	eb *adt.Environment, sb *adt.StructLit) bool {

 	// Create index of instance fields.
 	ca := newCollatedDecls()
 	ca.collate(ea, sa)

 	if ca.yielders != nil || ca.dynamic != nil {
 		// TODO: we could do structural comparison of comprehensions
 		// in many cases. For instance, an if clause would subsume
 		// structurally if it subsumes any of the if clauses in sb.
 		s.inexact = true
 		return false
 	}

 	cb := newCollatedDecls()
 	cb.collate(eb, sb)

 	if ca.hasOptional && !s.IgnoreOptional {
 		// TODO: same argument here as for comprehensions. This could
 		// be made to work.
 		if ca.pattern != nil || ca.dynamic != nil {
 			s.inexact = true
 			return false
 		}

 		// for f, b := range cb.fields {
 		// 	if !b.required || f.IsDef() {
 		// 		continue
 		// 	}
 		// 	name := ctx.LabelStr(b.Label)
 		// 	arg := &stringLit{x.baseValue, name, nil}
 		// 	u, _ := x.optionals.constraint(ctx, arg)
 		// 	if u != nil && !s.subsumes(u, b.v) {
 		// 		return false
 		// 	}
 		// }

 	}

 	return false

 }

 // collatedDecls is used to compute the structural subsumption of two
 // struct literals.
 type collatedDecls struct {
 	fields      map[adt.Feature]field
 	yielders    []adt.Yielder
 	pattern     []*adt.BulkOptionalField
 	dynamic     []*adt.DynamicField
 	values      []adt.Expr
 	additional  []*adt.Ellipsis
 	isOpen      bool
 	hasOptional bool
 }

 func newCollatedDecls() *collatedDecls {
 	return &collatedDecls{fields: map[adt.Feature]field{}}
 }

 type field struct {
 	required  bool
 	conjuncts []adt.Conjunct
 }

 func (c *collatedDecls) collate(env *adt.Environment, s *adt.StructLit) {
 	for _, d := range s.Decls {
 		switch x := d.(type) {
 		case *adt.Field:
 			e := c.fields[x.Label]
 			e.required = true
 			e.conjuncts = append(e.conjuncts, adt.MakeConjunct(env, x))
 			c.fields[x.Label] = e

 		case *adt.OptionalField:
 			e := c.fields[x.Label]
 			e.conjuncts = append(e.conjuncts, adt.MakeConjunct(env, x))
 			c.fields[x.Label] = e
 			c.hasOptional = true

 		case *adt.BulkOptionalField:
 			c.pattern = append(c.pattern, x)
 			c.hasOptional = true

 		case *adt.DynamicField:
 			c.dynamic = append(c.dynamic, x)
 			c.hasOptional = true

 		case *adt.Ellipsis:
 			c.isOpen = true
 			c.additional = append(c.additional, x)

 		case *adt.ForClause:
 			c.yielders = append(c.yielders, x)

 		case *adt.IfClause:
 			c.yielders = append(c.yielders, x)

 		case *adt.LetClause:
 		case *adt.ValueClause:
 		}
 	}
 }
	// Copyright 2020 CUE Authors
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.

	package subsume

	// TODO: structural subsumption has not yet been implemented.

	import "cuelang.org/go/internal/core/adt"

	func (s *subsumer) subsumes(gt, lt adt.Conjunct) bool {
	if gt == lt {
	return true
	}

	// First try evaluating at the value level.
	x, _ := gt.Expr().(adt.Value)
	y, _ := lt.Expr().(adt.Value)
	if x == nil {
	// Fall back to structural.
	return s.structural(gt, lt)
	}
	if y == nil {
	return false
	}

	return s.values(x, y)
	}

	func (s *subsumer) conjunct(gt, lt adt.Conjunct) bool {
	return false
	}

	func (s subsumer) c(env adt.Environment, x adt.Expr) adt.Conjunct {
	return adt.MakeConjunct(env, x)
	}

	func isBottomConjunct(c adt.Conjunct) bool {
	b, _ := c.Expr().(*adt.Bottom)
	return b != nil
	}

	func (s subsumer) node(env adt.Environment, up int32) *adt.Vertex {
	for ; up != 0; up-- {
	env = env.Up
	}
	return env.Vertex
	}

	func (s *subsumer) structural(a, b adt.Conjunct) bool {
	if y, ok := b.Expr().(*adt.LetReference); ok {
	return s.conjunct(a, s.c(b.Env, y.X))
	}
	if isBottomConjunct(b) {
	return true
	}

	switch x := a.Expr().(type) {
	case *adt.DisjunctionExpr:

	case *adt.StructLit:
	case *adt.ListLit:

	case *adt.FieldReference:
	if y, ok := b.Expr().(*adt.FieldReference); ok && x.Label == y.Label {
	if s.node(a.Env, x.UpCount) == s.node(b.Env, y.UpCount) {
	return true
	}
	}

	case *adt.LabelReference:
	if y, ok := b.Expr().(*adt.LabelReference); ok {
	if s.node(a.Env, x.UpCount) == s.node(b.Env, y.UpCount) {
	return true
	}
	}

	case *adt.DynamicReference:
	if y, ok := b.Expr().(*adt.FieldReference); ok {
	if s.node(a.Env, x.UpCount) == s.node(b.Env, y.UpCount) {
	return true
	}
	}

	case *adt.ImportReference:
	if y, ok := b.Expr().(*adt.ImportReference); ok &&
	x.ImportPath == y.ImportPath {
	return true
	}

	case *adt.LetReference:
	return s.conjunct(s.c(a.Env, x.X), b)

	case *adt.SelectorExpr:
	if y, ok := a.Expr().(*adt.SelectorExpr); ok &&
	x.Sel == y.Sel &&
	s.conjunct(s.c(a.Env, x.X), s.c(b.Env, y.X)) {
	return true
	}

	case *adt.IndexExpr:
	if y, ok := b.Expr().(*adt.IndexExpr); ok &&
	s.conjunct(s.c(a.Env, x.X), s.c(b.Env, y.X)) &&
	s.conjunct(s.c(a.Env, x.Index), s.c(b.Env, y.Index)) {
	return true
	}

	case *adt.SliceExpr:
	if r, ok := b.Expr().(*adt.SliceExpr); ok &&
	s.conjunct(s.c(a.Env, x.X), s.c(b.Env, r.X)) &&
	s.conjunct(s.c(a.Env, x.Lo), s.c(b.Env, r.Lo)) &&
	s.conjunct(s.c(a.Env, x.Hi), s.c(b.Env, r.Hi)) {
	return true
	}

	case *adt.Interpolation:
	switch y := b.Expr().(type) {
	case *adt.String:
	// Be conservative if not ground.
	s.inexact = true

	case *adt.Interpolation:
	// structural equivalence
	if len(x.Parts) != len(y.Parts) {
	return false
	}
	for i, p := range x.Parts {
	if !s.conjunct(s.c(a.Env, p), s.c(b.Env, y.Parts[i])) {
	return false
	}
	}
	return true
	}

	case *adt.BoundExpr:
	if y, ok := b.Expr().(*adt.BoundExpr); ok && x.Op == y.Op {
	return s.conjunct(s.c(a.Env, x.Expr), s.c(b.Env, y.Expr))
	}

	case *adt.UnaryExpr:
	if y, ok := b.Expr().(*adt.UnaryExpr); ok && x.Op == y.Op {
	return s.conjunct(s.c(a.Env, x.X), s.c(b.Env, y.X))
	}

	case *adt.BinaryExpr:
	if y, ok := b.Expr().(*adt.BinaryExpr); ok && x.Op == y.Op {
	return s.conjunct(s.c(a.Env, x.X), s.c(b.Env, y.X)) &&
	s.conjunct(s.c(a.Env, x.Y), s.c(b.Env, y.Y))
	}

	case *adt.CallExpr:
	if y, ok := b.Expr().(*adt.CallExpr); ok {
	if len(x.Args) != len(y.Args) {
	return false
	}
	for i, arg := range x.Args {
	if !s.conjunct(s.c(a.Env, arg), s.c(b.Env, y.Args[i])) {
	return false
	}
	}
	return s.conjunct(s.c(a.Env, x.Fun), s.c(b.Env, y.Fun))
	}
	}
	return false
	}

	func (s *subsumer) structLit(
	ea adt.Environment, sa adt.StructLit,
	eb adt.Environment, sb adt.StructLit) bool {

	// Create index of instance fields.
	ca := newCollatedDecls()
	ca.collate(ea, sa)

	if ca.yielders != nil \|\| ca.dynamic != nil {
	// TODO: we could do structural comparison of comprehensions
	// in many cases. For instance, an if clause would subsume
	// structurally if it subsumes any of the if clauses in sb.
	s.inexact = true
	return false
	}

	cb := newCollatedDecls()
	cb.collate(eb, sb)

	if ca.hasOptional && !s.IgnoreOptional {
	// TODO: same argument here as for comprehensions. This could
	// be made to work.
	if ca.pattern != nil \|\| ca.dynamic != nil {
	s.inexact = true
	return false
	}

	// for f, b := range cb.fields {
	// if !b.required \|\| f.IsDef() {
	// continue
	// }
	// name := ctx.LabelStr(b.Label)
	// arg := &stringLit{x.baseValue, name, nil}
	// u, _ := x.optionals.constraint(ctx, arg)
	// if u != nil && !s.subsumes(u, b.v) {
	// return false
	// }
	// }

	}

	return false

	}

	// collatedDecls is used to compute the structural subsumption of two
	// struct literals.
	type collatedDecls struct {
	fields map[adt.Feature]field
	yielders []adt.Yielder
	pattern []*adt.BulkOptionalField
	dynamic []*adt.DynamicField
	values []adt.Expr
	additional []*adt.Ellipsis
	isOpen bool
	hasOptional bool
	}

	func newCollatedDecls() *collatedDecls {
	return &collatedDecls{fields: map[adt.Feature]field{}}
	}

	type field struct {
	required bool
	conjuncts []adt.Conjunct
	}

	func (c collatedDecls) collate(env adt.Environment, s *adt.StructLit) {
	for _, d := range s.Decls {
	switch x := d.(type) {
	case *adt.Field:
	e := c.fields[x.Label]
	e.required = true
	e.conjuncts = append(e.conjuncts, adt.MakeConjunct(env, x))
	c.fields[x.Label] = e

	case *adt.OptionalField:
	e := c.fields[x.Label]
	e.conjuncts = append(e.conjuncts, adt.MakeConjunct(env, x))
	c.fields[x.Label] = e
	c.hasOptional = true

	case *adt.BulkOptionalField:
	c.pattern = append(c.pattern, x)
	c.hasOptional = true

	case *adt.DynamicField:
	c.dynamic = append(c.dynamic, x)
	c.hasOptional = true

	case *adt.Ellipsis:
	c.isOpen = true
	c.additional = append(c.additional, x)

	case *adt.ForClause:
	c.yielders = append(c.yielders, x)

	case *adt.IfClause:
	c.yielders = append(c.yielders, x)

	case *adt.LetClause:
	case *adt.ValueClause:
	}
	}
	}