yq/pkg/yqlib/treeops/path_tokeniser.go
2020-11-02 11:20:52 +11:00

291 lines
8.4 KiB
Go

package treeops
import (
"fmt"
"strconv"
lex "github.com/timtadh/lexmachine"
"github.com/timtadh/lexmachine/machines"
)
func skip(*lex.Scanner, *machines.Match) (interface{}, error) {
return nil, nil
}
type TokenType uint32
const (
OperationToken = 1 << iota
OpenBracket
CloseBracket
OpenCollect
CloseCollect
OpenCollectObject
CloseCollectObject
)
type Token struct {
TokenType TokenType
Operation *Operation
CheckForPostTraverse bool // e.g. [1]cat should really be [1].cat
}
func (t *Token) toString() string {
if t.TokenType == OperationToken {
return t.Operation.toString()
} else if t.TokenType == OpenBracket {
return "("
} else if t.TokenType == CloseBracket {
return ")"
} else if t.TokenType == OpenCollect {
return "["
} else if t.TokenType == CloseCollect {
return "]"
} else if t.TokenType == OpenCollectObject {
return "{"
} else if t.TokenType == CloseCollectObject {
return "}"
} else {
return fmt.Sprintf("NFI")
}
}
func pathToken(wrapped bool) lex.Action {
return func(s *lex.Scanner, m *machines.Match) (interface{}, error) {
value := string(m.Bytes)
value = value[1:len(value)]
if wrapped {
value = unwrap(value)
}
op := &Operation{OperationType: TraversePath, Value: value, StringValue: value}
return &Token{TokenType: OperationToken, Operation: op, CheckForPostTraverse: true}, nil
}
}
func literalPathToken(value string) lex.Action {
return func(s *lex.Scanner, m *machines.Match) (interface{}, error) {
op := &Operation{OperationType: TraversePath, Value: value, StringValue: value}
return &Token{TokenType: OperationToken, Operation: op, CheckForPostTraverse: true}, nil
}
}
func documentToken() lex.Action {
return func(s *lex.Scanner, m *machines.Match) (interface{}, error) {
var numberString = string(m.Bytes)
numberString = numberString[1:len(numberString)]
var number, errParsingInt = strconv.ParseInt(numberString, 10, 64) // nolint
if errParsingInt != nil {
return nil, errParsingInt
}
op := &Operation{OperationType: DocumentFilter, Value: number, StringValue: numberString}
return &Token{TokenType: OperationToken, Operation: op, CheckForPostTraverse: true}, nil
}
}
func opToken(op *OperationType) lex.Action {
return func(s *lex.Scanner, m *machines.Match) (interface{}, error) {
value := string(m.Bytes)
op := &Operation{OperationType: op, Value: op.Type, StringValue: value}
return &Token{TokenType: OperationToken, Operation: op}, nil
}
}
func literalToken(pType TokenType, checkForPost bool) lex.Action {
return func(s *lex.Scanner, m *machines.Match) (interface{}, error) {
return &Token{TokenType: pType, CheckForPostTraverse: checkForPost}, nil
}
}
func unwrap(value string) string {
return value[1 : len(value)-1]
}
func arrayIndextoken(precedingDot bool) lex.Action {
return func(s *lex.Scanner, m *machines.Match) (interface{}, error) {
var numberString = string(m.Bytes)
startIndex := 1
if precedingDot {
startIndex = 2
}
numberString = numberString[startIndex : len(numberString)-1]
var number, errParsingInt = strconv.ParseInt(numberString, 10, 64) // nolint
if errParsingInt != nil {
return nil, errParsingInt
}
op := &Operation{OperationType: TraversePath, Value: number, StringValue: numberString}
return &Token{TokenType: OperationToken, Operation: op, CheckForPostTraverse: true}, nil
}
}
func numberValue() lex.Action {
return func(s *lex.Scanner, m *machines.Match) (interface{}, error) {
var numberString = string(m.Bytes)
var number, errParsingInt = strconv.ParseInt(numberString, 10, 64) // nolint
if errParsingInt != nil {
return nil, errParsingInt
}
return &Token{TokenType: OperationToken, Operation: CreateValueOperation(number, numberString)}, nil
}
}
func floatValue() lex.Action {
return func(s *lex.Scanner, m *machines.Match) (interface{}, error) {
var numberString = string(m.Bytes)
var number, errParsingInt = strconv.ParseFloat(numberString, 64) // nolint
if errParsingInt != nil {
return nil, errParsingInt
}
return &Token{TokenType: OperationToken, Operation: CreateValueOperation(number, numberString)}, nil
}
}
func booleanValue(val bool) lex.Action {
return func(s *lex.Scanner, m *machines.Match) (interface{}, error) {
return &Token{TokenType: OperationToken, Operation: CreateValueOperation(val, string(m.Bytes))}, nil
}
}
func stringValue(wrapped bool) lex.Action {
return func(s *lex.Scanner, m *machines.Match) (interface{}, error) {
value := string(m.Bytes)
if wrapped {
value = unwrap(value)
}
return &Token{TokenType: OperationToken, Operation: CreateValueOperation(value, value)}, nil
}
}
func nullValue() lex.Action {
return func(s *lex.Scanner, m *machines.Match) (interface{}, error) {
return &Token{TokenType: OperationToken, Operation: CreateValueOperation(nil, string(m.Bytes))}, nil
}
}
func selfToken() lex.Action {
return func(s *lex.Scanner, m *machines.Match) (interface{}, error) {
op := &Operation{OperationType: SelfReference}
return &Token{TokenType: OperationToken, Operation: op}, nil
}
}
// Creates the lexer object and compiles the NFA.
func initLexer() (*lex.Lexer, error) {
lexer := lex.NewLexer()
lexer.Add([]byte(`\(`), literalToken(OpenBracket, false))
lexer.Add([]byte(`\)`), literalToken(CloseBracket, true))
lexer.Add([]byte(`\.?\[\]`), literalPathToken("[]"))
lexer.Add([]byte(`\.\.`), opToken(RecursiveDescent))
lexer.Add([]byte(`,`), opToken(Union))
lexer.Add([]byte(`:\s*`), opToken(CreateMap))
lexer.Add([]byte(`length`), opToken(Length))
lexer.Add([]byte(`select`), opToken(Select))
lexer.Add([]byte(`explode`), opToken(Explode))
lexer.Add([]byte(`or`), opToken(Or))
lexer.Add([]byte(`not`), opToken(Not))
lexer.Add([]byte(`style\s*=`), opToken(AssignStyle))
lexer.Add([]byte(`style`), opToken(GetStyle))
// lexer.Add([]byte(`and`), opToken())
lexer.Add([]byte(`collect`), opToken(Collect))
lexer.Add([]byte(`\s*==\s*`), opToken(Equals))
lexer.Add([]byte(`\s*.-\s*`), opToken(DeleteChild))
lexer.Add([]byte(`\s*\|=\s*`), opToken(Assign))
lexer.Add([]byte(`\[-?[0-9]+\]`), arrayIndextoken(false))
lexer.Add([]byte(`\.\[-?[0-9]+\]`), arrayIndextoken(true))
lexer.Add([]byte("( |\t|\n|\r)+"), skip)
lexer.Add([]byte(`d[0-9]+`), documentToken()) // $0
lexer.Add([]byte(`\."[^ "]+"`), pathToken(true))
lexer.Add([]byte(`\.[^ \}\{\:\[\],\|\.\[\(\)=]+`), pathToken(false))
lexer.Add([]byte(`\.`), selfToken())
lexer.Add([]byte(`\|`), opToken(Pipe))
lexer.Add([]byte(`-?\d+(\.\d+)`), floatValue())
lexer.Add([]byte(`-?[1-9](\.\d+)?[Ee][-+]?\d+`), floatValue())
lexer.Add([]byte(`-?\d+`), numberValue())
lexer.Add([]byte(`[Tt][Rr][Uu][Ee]`), booleanValue(true))
lexer.Add([]byte(`[Ff][Aa][Ll][Ss][Ee]`), booleanValue(false))
lexer.Add([]byte(`[Nn][Uu][Ll][Ll]`), nullValue())
lexer.Add([]byte(`~`), nullValue())
lexer.Add([]byte(`"[^ "]*"`), stringValue(true))
lexer.Add([]byte(`\[`), literalToken(OpenCollect, false))
lexer.Add([]byte(`\]`), literalToken(CloseCollect, true))
lexer.Add([]byte(`\{`), literalToken(OpenCollectObject, false))
lexer.Add([]byte(`\}`), literalToken(CloseCollectObject, true))
lexer.Add([]byte(`\*`), opToken(Multiply))
// lexer.Add([]byte(`[^ \,\|\.\[\(\)=]+`), stringValue(false))
err := lexer.Compile()
if err != nil {
return nil, err
}
return lexer, nil
}
type PathTokeniser interface {
Tokenise(path string) ([]*Token, error)
}
type pathTokeniser struct {
lexer *lex.Lexer
}
func NewPathTokeniser() PathTokeniser {
var lexer, err = initLexer()
if err != nil {
panic(err)
}
return &pathTokeniser{lexer}
}
func (p *pathTokeniser) Tokenise(path string) ([]*Token, error) {
scanner, err := p.lexer.Scanner([]byte(path))
if err != nil {
return nil, err
}
var tokens []*Token
for tok, err, eof := scanner.Next(); !eof; tok, err, eof = scanner.Next() {
if tok != nil {
token := tok.(*Token)
log.Debugf("Tokenising %v", token.toString())
tokens = append(tokens, token)
}
if err != nil {
return nil, err
}
}
var postProcessedTokens = make([]*Token, 0)
for index, token := range tokens {
postProcessedTokens = append(postProcessedTokens, token)
if index != len(tokens)-1 && token.CheckForPostTraverse &&
tokens[index+1].TokenType == OperationToken &&
tokens[index+1].Operation.OperationType == TraversePath {
op := &Operation{OperationType: Pipe, Value: "PIPE"}
postProcessedTokens = append(postProcessedTokens, &Token{TokenType: OperationToken, Operation: op})
}
}
return postProcessedTokens, nil
}