Function NewExpressionAbsTraversal

hclwrite/ast_expression.go:72–128

NewExpressionAbsTraversal constructs an expression that represents the given traversal, which must be absolute or this function will panic.

(traversal hcl.Traversal)

// NewExpressionAbsTraversal constructs an expression that represents the
// given traversal, which must be absolute or this function will panic.
func NewExpressionAbsTraversal(traversal hcl.Traversal) *Expression {
	if traversal.IsRelative() {
		panic("can't construct expression from relative traversal")
	}

	physT := newTraversal()
	rootName := traversal.RootName()
	steps := traversal[1:]

	{
		tn := newTraverseName()
		tn.name = tn.children.Append(newIdentifier(&Token{
			Type:  hclsyntax.TokenIdent,
			Bytes: []byte(rootName),
		}))
		physT.steps.Add(physT.children.Append(tn))
	}

	for _, step := range steps {
		switch ts := step.(type) {
		case hcl.TraverseAttr:
			tn := newTraverseName()
			tn.children.AppendUnstructuredTokens(Tokens{
				{
					Type:  hclsyntax.TokenDot,
					Bytes: []byte{'.'},
				},
			})
			tn.name = tn.children.Append(newIdentifier(&Token{
				Type:  hclsyntax.TokenIdent,
				Bytes: []byte(ts.Name),
			}))
			physT.steps.Add(physT.children.Append(tn))
		case hcl.TraverseIndex:
			ti := newTraverseIndex()
			ti.children.AppendUnstructuredTokens(Tokens{
				{
					Type:  hclsyntax.TokenOBrack,
					Bytes: []byte{'['},
				},
			})
			indexExpr := NewExpressionLiteral(ts.Key)
			ti.key = ti.children.Append(indexExpr)
			ti.children.AppendUnstructuredTokens(Tokens{
				{
					Type:  hclsyntax.TokenCBrack,
					Bytes: []byte{']'},
				},
			})
			physT.steps.Add(physT.children.Append(ti))
		}
	}

	expr := newExpression()
	expr.absTraversals.Add(expr.children.Append(physT))
	return expr
}