159 lines
3.2 KiB
Go
159 lines
3.2 KiB
Go
package parse
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import (
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"bufio"
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"errors"
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"fmt"
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"io"
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)
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type CommitType int
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const (
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None CommitType = 0
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Alias CommitType = 1 << iota
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Documentation
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Root
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)
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type Syntax struct {
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trace Trace
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registry *registry
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initialized bool
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initFailed bool
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rootSet bool
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root definition
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parser parser
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}
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var (
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ErrSyntaxInitialized = errors.New("syntax initialized")
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ErrInitFailed = errors.New("init failed")
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ErrNoParsersDefined = errors.New("no parsers defined")
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ErrInvalidInput = errors.New("invalid input")
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ErrInvalidCharacter = errors.New("invalid character") // two use cases: utf8 and boot
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ErrUnexpectedCharacter = errors.New("unexpected character")
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ErrInvalidSyntax = errors.New("invalid syntax")
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ErrRootAlias = errors.New("root node cannot be an alias")
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)
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func duplicateDefinition(name string) error {
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return fmt.Errorf("duplicate definition: %s", name)
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}
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func NewSyntax(t Trace) *Syntax {
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if t == nil {
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t = NewTrace(0)
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}
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return &Syntax{
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trace: t,
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registry: newRegistry(),
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}
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}
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func (s *Syntax) register(d definition) error {
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if s.initialized {
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return ErrSyntaxInitialized
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}
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if d.commitType()&Root != 0 {
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s.root = d
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s.rootSet = true
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} else if !s.rootSet {
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s.root = d
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}
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return s.registry.setDefinition(d)
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}
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func (s *Syntax) AnyChar(name string, ct CommitType) error {
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return s.register(newChar(name, ct, true, false, nil, nil))
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}
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func (s *Syntax) Class(name string, ct CommitType, not bool, chars []rune, ranges [][]rune) error {
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return s.register(newChar(name, ct, false, not, chars, ranges))
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}
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func childName(name string, childIndex int) string {
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return fmt.Sprintf("%s:%d", name, childIndex)
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}
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func (s *Syntax) CharSequence(name string, ct CommitType, chars []rune) error {
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var refs []string
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for i, ci := range chars {
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ref := childName(name, i)
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refs = append(refs, ref)
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if err := s.register(newChar(ref, Alias, false, false, []rune{ci}, nil)); err != nil {
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return err
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}
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}
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return s.Sequence(name, ct, refs...)
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}
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func (s *Syntax) Quantifier(name string, ct CommitType, item string, min, max int) error {
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return s.register(newQuantifier(name, ct, item, min, max))
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}
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func (s *Syntax) Sequence(name string, ct CommitType, items ...string) error {
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return s.register(newSequence(name, ct, items))
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}
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func (s *Syntax) Choice(name string, ct CommitType, elements ...string) error {
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return s.register(newChoice(name, ct, elements))
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}
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func (s *Syntax) Read(r io.Reader) error {
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if s.initialized {
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return ErrSyntaxInitialized
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}
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return nil
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}
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func (s *Syntax) Init() error {
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if s.initFailed {
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return ErrInitFailed
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}
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if s.initialized {
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return nil
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}
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if s.root == nil {
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return ErrNoParsersDefined
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}
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if s.root.commitType()&Alias != 0 {
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return ErrRootAlias
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}
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var err error
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s.parser, err = s.root.parser(s.registry, nil)
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if err != nil {
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s.initFailed = true
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return err
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}
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s.initialized = true
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return nil
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}
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func (s *Syntax) Generate(w io.Writer) error {
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if err := s.Init(); err != nil {
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return err
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}
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return nil
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}
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func (s *Syntax) Parse(r io.Reader) (*Node, error) {
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if err := s.Init(); err != nil {
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return nil, err
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}
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c := newContext(bufio.NewReader(r))
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return parse(s.trace, s.parser, c)
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}
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