dc2d91e294
This allows consumers to change the inputs to an expression and re-run typechecking to compute the expression's new type.
113 lines
3.2 KiB
Go
113 lines
3.2 KiB
Go
// Copyright 2016-2020, Pulumi Corporation.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package model
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import (
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"strings"
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"github.com/hashicorp/hcl/v2"
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"github.com/pulumi/pulumi/sdk/v2/go/common/util/contract"
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"github.com/zclconf/go-cty/cty"
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)
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// Traversable represents an entity that can be traversed by an HCL2 traverser.
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type Traversable interface {
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// Traverse attempts to traverse the receiver using the given traverser.
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Traverse(t hcl.Traverser) (Traversable, hcl.Diagnostics)
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}
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// TypedTraversable is a Traversable that has an associated type.
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type TypedTraversable interface {
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Traversable
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Type() Type
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}
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// ValueTraversable is a Traversable that has an associated value.
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type ValueTraversable interface {
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Traversable
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Value(context *hcl.EvalContext) (cty.Value, hcl.Diagnostics)
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}
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// GetTraversableType returns the type of the given Traversable:
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// - If the Traversable is a TypedTraversable, this returns t.Type()
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// - If the Traversable is a Type, this returns t
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// - Otherwise, this returns DynamicType
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func GetTraversableType(t Traversable) Type {
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switch t := t.(type) {
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case TypedTraversable:
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return t.Type()
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case Type:
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return t
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default:
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return DynamicType
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}
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}
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// GetTraverserKey extracts the value and type of the key associated with the given traverser.
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func GetTraverserKey(t hcl.Traverser) (cty.Value, Type) {
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switch t := t.(type) {
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case hcl.TraverseAttr:
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return cty.StringVal(t.Name), StringType
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case hcl.TraverseIndex:
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if t.Key.Type().Equals(typeCapsule) {
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return cty.DynamicVal, *(t.Key.EncapsulatedValue().(*Type))
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}
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return t.Key, ctyTypeToType(t.Key.Type(), false)
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default:
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contract.Failf("unexpected traverser of type %T (%v)", t, t.SourceRange())
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return cty.DynamicVal, DynamicType
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}
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}
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// bindTraversalParts computes the type for each element of the given traversal.
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func bindTraversalParts(receiver Traversable, traversal hcl.Traversal,
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allowMissingVariables bool) ([]Traversable, hcl.Diagnostics) {
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parts := make([]Traversable, len(traversal)+1)
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parts[0] = receiver
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var diagnostics hcl.Diagnostics
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for i, part := range traversal {
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nextReceiver, partDiags := parts[i].Traverse(part)
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// TODO(pdg): proper options for Traverse
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if allowMissingVariables {
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var diags hcl.Diagnostics
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for _, d := range partDiags {
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if !strings.HasPrefix(d.Summary, "undefined variable") {
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diags = append(diags, d)
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}
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}
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partDiags = diags
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}
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parts[i+1], diagnostics = nextReceiver, append(diagnostics, partDiags...)
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}
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switch parts[len(parts)-1].(type) {
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case TypedTraversable, Type:
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// OK
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default:
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// TODO(pdg): improve this diagnostic
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if !allowMissingVariables {
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diagnostics = append(diagnostics, undefinedVariable("", traversal.SourceRange()))
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}
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}
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return parts, diagnostics
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}
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