| // Copyright 2021 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 cue |
| |
| import ( |
| "cuelang.org/go/cue/ast" |
| "cuelang.org/go/cue/ast/astutil" |
| "cuelang.org/go/cue/token" |
| "cuelang.org/go/internal/core/adt" |
| "cuelang.org/go/internal/core/compile" |
| ) |
| |
| // This file contains query-related code. |
| |
| // getScopePrefix finds the Vertex that exists in v for the longest prefix of p. |
| // |
| // It is used to make the parent scopes visible when resolving expressions. |
| func getScopePrefix(v Value, p Path) *adt.Vertex { |
| for _, sel := range p.Selectors() { |
| w := v.LookupPath(MakePath(sel)) |
| if !w.Exists() { |
| break |
| } |
| v = w |
| } |
| return v.v |
| } |
| |
| func errFn(pos token.Pos, msg string, args ...interface{}) {} |
| |
| // resolveExpr binds unresolved expressions to values in the expression or v. |
| func resolveExpr(ctx *adt.OpContext, v *adt.Vertex, x ast.Expr) adt.Value { |
| cfg := &compile.Config{Scope: v} |
| |
| astutil.ResolveExpr(x, errFn) |
| |
| c, err := compile.Expr(cfg, ctx, pkgID(), x) |
| if err != nil { |
| return &adt.Bottom{Err: err} |
| } |
| return adt.Resolve(ctx, c) |
| } |
| |
| // LookupPath reports the value for path p relative to v. |
| func (v Value) LookupPath(p Path) Value { |
| if v.v == nil { |
| return Value{} |
| } |
| n := v.v |
| ctx := v.ctx() |
| |
| outer: |
| for _, sel := range p.path { |
| f := sel.sel.feature(v.idx) |
| for _, a := range n.Arcs { |
| if a.Label == f { |
| n = a |
| continue outer |
| } |
| } |
| if sel.sel.optional() { |
| x := &adt.Vertex{ |
| Parent: v.v, |
| Label: sel.sel.feature(ctx), |
| } |
| n.MatchAndInsert(ctx, x) |
| if len(x.Conjuncts) > 0 { |
| x.Finalize(ctx) |
| n = x |
| continue |
| } |
| } |
| |
| var x *adt.Bottom |
| if err, ok := sel.sel.(pathError); ok { |
| x = &adt.Bottom{Err: err.Error} |
| } else { |
| // TODO: better message. |
| x = mkErr(v.idx, n, adt.NotExistError, "field %q not found", sel.sel) |
| } |
| v := makeValue(v.idx, n) |
| return newErrValue(v, x) |
| } |
| return makeValue(v.idx, n) |
| } |