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// Copyright 2018 The 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.
// This file contains the exported entry points for invoking the
package parser
import (
"cuelang.org/go/cue/ast"
"cuelang.org/go/cue/errors"
"cuelang.org/go/cue/token"
"cuelang.org/go/internal/source"
)
// Option specifies a parse option.
type Option func(p *parser)
var (
// PackageClauseOnly causes parsing to stop after the package clause.
PackageClauseOnly Option = packageClauseOnly
packageClauseOnly = func(p *parser) {
p.mode |= packageClauseOnlyMode
}
// ImportsOnly causes parsing to stop parsing after the import declarations.
ImportsOnly Option = importsOnly
importsOnly = func(p *parser) {
p.mode |= importsOnlyMode
}
// ParseComments causes comments to be parsed.
ParseComments Option = parseComments
parseComments = func(p *parser) {
p.mode |= parseCommentsMode
}
// Trace causes parsing to print a trace of parsed productions.
Trace Option = traceOpt
traceOpt = func(p *parser) {
p.mode |= traceMode
}
// DeclarationErrors causes parsing to report declaration errors.
DeclarationErrors Option = declarationErrors
declarationErrors = func(p *parser) {
p.mode |= declarationErrorsMode
}
// AllErrors causes all errors to be reported (not just the first 10 on different lines).
AllErrors Option = allErrors
allErrors = func(p *parser) {
p.mode |= allErrorsMode
}
// AllowPartial allows the parser to be used on a prefix buffer.
AllowPartial Option = allowPartial
allowPartial = func(p *parser) {
p.mode |= partialMode
}
)
// A mode value is a set of flags (or 0).
// They control the amount of source code parsed and other optional
// parser functionality.
type mode uint
const (
packageClauseOnlyMode mode = 1 << iota // stop parsing after package clause
importsOnlyMode // stop parsing after import declarations
parseCommentsMode // parse comments and add them to AST
partialMode
traceMode // print a trace of parsed productions
declarationErrorsMode // report declaration errors
allErrorsMode // report all errors (not just the first 10 on different lines)
)
// ParseFile parses the source code of a single CUE source file and returns
// the corresponding File node. The source code may be provided via
// the filename of the source file, or via the src parameter.
//
// If src != nil, ParseFile parses the source from src and the filename is
// only used when recording position information. The type of the argument
// for the src parameter must be string, []byte, or io.Reader.
// If src == nil, ParseFile parses the file specified by filename.
//
// The mode parameter controls the amount of source text parsed and other
// optional parser functionality. Position information is recorded in the
// file set fset, which must not be nil.
//
// If the source couldn't be read, the returned AST is nil and the error
// indicates the specific failure. If the source was read but syntax
// errors were found, the result is a partial AST (with Bad* nodes
// representing the fragments of erroneous source code). Multiple errors
// are returned via a ErrorList which is sorted by file position.
func ParseFile(filename string, src interface{}, mode ...Option) (f *ast.File, err error) {
// get source
text, err := source.Read(filename, src)
if err != nil {
return nil, err
}
var pp parser
defer func() {
if pp.panicking {
_ = recover()
}
// set result values
if f == nil {
// source is not a valid Go source file - satisfy
// ParseFile API and return a valid (but) empty
// *File
f = &ast.File{
Name: new(ast.Ident),
// Scope: NewScope(nil),
}
}
err = errors.Sanitize(pp.errors)
}()
// parse source
pp.init(filename, text, mode)
f = pp.parseFile()
if f == nil {
return nil, pp.errors
}
f.Filename = filename
resolve(f, pp.errf)
return
}
// ParseExpr is a convenience function for parsing an expression.
// The arguments have the same meaning as for Parse, but the source must
// be a valid CUE (type or value) expression. Specifically, fset must not
// be nil.
func ParseExpr(filename string, src interface{}, mode ...Option) (ast.Expr, error) {
// get source
text, err := source.Read(filename, src)
if err != nil {
return nil, err
}
var p parser
defer func() {
if p.panicking {
_ = recover()
}
err = errors.Sanitize(p.errors)
}()
// parse expr
p.init(filename, text, mode)
// Set up pkg-level scopes to avoid nil-pointer errors.
// This is not needed for a correct expression x as the
// parser will be ok with a nil topScope, but be cautious
// in case of an erroneous x.
e := p.parseRHS()
// If a comma was inserted, consume it;
// report an error if there's more tokens.
if p.tok == token.COMMA && p.lit == "\n" {
p.next()
}
if p.mode&partialMode == 0 {
p.expect(token.EOF)
}
if p.errors != nil {
return nil, p.errors
}
resolveExpr(e, p.errf)
return e, nil
}
// parseExprString is a convenience function for obtaining the AST of an
// expression x. The position information recorded in the AST is undefined. The
// filename used in error messages is the empty string.
func parseExprString(x string) (ast.Expr, error) {
return ParseExpr("", []byte(x))
}