/
parser_traversal.go
211 lines (184 loc) · 5.92 KB
/
parser_traversal.go
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// Copyright (c) HashiCorp, Inc.
// SPDX-License-Identifier: MPL-2.0
package hclsyntax
import (
"github.com/zclconf/go-cty/cty"
"github.com/hashicorp/hcl/v2"
)
// ParseTraversalAbs parses an absolute traversal that is assumed to consume
// all of the remaining tokens in the peeker. The usual parser recovery
// behavior is not supported here because traversals are not expected to
// be parsed as part of a larger program.
func (p *parser) ParseTraversalAbs() (hcl.Traversal, hcl.Diagnostics) {
return p.parseTraversal(false)
}
// ParseTraversalPartial parses an absolute traversal that is permitted
// to contain splat ([*]) expressions. Only splat expressions within square
// brackets are permitted ([*]); splat expressions within attribute names are
// not permitted (.*).
//
// The meaning of partial here is that the traversal may be incomplete, in that
// any splat expression indicates reference to a potentially unknown number of
// elements.
//
// Traversals that include splats cannot be automatically traversed by HCL using
// the TraversalAbs or TraversalRel methods. Instead, the caller must handle
// the traversals manually.
func (p *parser) ParseTraversalPartial() (hcl.Traversal, hcl.Diagnostics) {
return p.parseTraversal(true)
}
func (p *parser) parseTraversal(allowSplats bool) (hcl.Traversal, hcl.Diagnostics) {
var ret hcl.Traversal
var diags hcl.Diagnostics
// Absolute traversal must always begin with a variable name
varTok := p.Read()
if varTok.Type != TokenIdent {
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Variable name required",
Detail: "Must begin with a variable name.",
Subject: &varTok.Range,
})
return ret, diags
}
varName := string(varTok.Bytes)
ret = append(ret, hcl.TraverseRoot{
Name: varName,
SrcRange: varTok.Range,
})
for {
next := p.Peek()
if next.Type == TokenEOF {
return ret, diags
}
switch next.Type {
case TokenDot:
// Attribute access
dot := p.Read() // eat dot
nameTok := p.Read()
if nameTok.Type != TokenIdent {
if nameTok.Type == TokenStar {
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Attribute name required",
Detail: "Splat expressions (.*) may not be used here.",
Subject: &nameTok.Range,
Context: hcl.RangeBetween(varTok.Range, nameTok.Range).Ptr(),
})
} else {
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Attribute name required",
Detail: "Dot must be followed by attribute name.",
Subject: &nameTok.Range,
Context: hcl.RangeBetween(varTok.Range, nameTok.Range).Ptr(),
})
}
return ret, diags
}
attrName := string(nameTok.Bytes)
ret = append(ret, hcl.TraverseAttr{
Name: attrName,
SrcRange: hcl.RangeBetween(dot.Range, nameTok.Range),
})
case TokenOBrack:
// Index
open := p.Read() // eat open bracket
next := p.Peek()
switch next.Type {
case TokenNumberLit:
tok := p.Read() // eat number
numVal, numDiags := p.numberLitValue(tok)
diags = append(diags, numDiags...)
close := p.Read()
if close.Type != TokenCBrack {
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Unclosed index brackets",
Detail: "Index key must be followed by a closing bracket.",
Subject: &close.Range,
Context: hcl.RangeBetween(open.Range, close.Range).Ptr(),
})
}
ret = append(ret, hcl.TraverseIndex{
Key: numVal,
SrcRange: hcl.RangeBetween(open.Range, close.Range),
})
if diags.HasErrors() {
return ret, diags
}
case TokenOQuote:
str, _, strDiags := p.parseQuotedStringLiteral()
diags = append(diags, strDiags...)
close := p.Read()
if close.Type != TokenCBrack {
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Unclosed index brackets",
Detail: "Index key must be followed by a closing bracket.",
Subject: &close.Range,
Context: hcl.RangeBetween(open.Range, close.Range).Ptr(),
})
}
ret = append(ret, hcl.TraverseIndex{
Key: cty.StringVal(str),
SrcRange: hcl.RangeBetween(open.Range, close.Range),
})
if diags.HasErrors() {
return ret, diags
}
case TokenStar:
if allowSplats {
p.Read() // Eat the star.
close := p.Read()
if close.Type != TokenCBrack {
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Unclosed index brackets",
Detail: "Index key must be followed by a closing bracket.",
Subject: &close.Range,
Context: hcl.RangeBetween(open.Range, close.Range).Ptr(),
})
}
ret = append(ret, hcl.TraverseSplat{
SrcRange: hcl.RangeBetween(open.Range, close.Range),
})
if diags.HasErrors() {
return ret, diags
}
continue
}
// Otherwise, return the error below for the star.
fallthrough
default:
if next.Type == TokenStar {
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Attribute name required",
Detail: "Splat expressions ([*]) may not be used here.",
Subject: &next.Range,
Context: hcl.RangeBetween(varTok.Range, next.Range).Ptr(),
})
} else {
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Index value required",
Detail: "Index brackets must contain either a literal number or a literal string.",
Subject: &next.Range,
Context: hcl.RangeBetween(varTok.Range, next.Range).Ptr(),
})
}
return ret, diags
}
default:
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Invalid character",
Detail: "Expected an attribute access or an index operator.",
Subject: &next.Range,
Context: hcl.RangeBetween(varTok.Range, next.Range).Ptr(),
})
return ret, diags
}
}
}