mirror of
https://github.com/thegeeklab/wp-matrix.git
synced 2024-11-12 17:20:40 +00:00
847 lines
18 KiB
Go
847 lines
18 KiB
Go
// Package parser provides a handlebars syntax analyser. It consumes the tokens provided by the lexer to build an AST.
|
|
package parser
|
|
|
|
import (
|
|
"fmt"
|
|
"regexp"
|
|
"runtime"
|
|
"strconv"
|
|
|
|
"github.com/aymerick/raymond/ast"
|
|
"github.com/aymerick/raymond/lexer"
|
|
)
|
|
|
|
// References:
|
|
// - https://github.com/wycats/handlebars.js/blob/master/src/handlebars.yy
|
|
// - https://github.com/golang/go/blob/master/src/text/template/parse/parse.go
|
|
|
|
// parser is a syntax analyzer.
|
|
type parser struct {
|
|
// Lexer
|
|
lex *lexer.Lexer
|
|
|
|
// Root node
|
|
root ast.Node
|
|
|
|
// Tokens parsed but not consumed yet
|
|
tokens []*lexer.Token
|
|
|
|
// All tokens have been retreieved from lexer
|
|
lexOver bool
|
|
}
|
|
|
|
var (
|
|
rOpenComment = regexp.MustCompile(`^\{\{~?!-?-?`)
|
|
rCloseComment = regexp.MustCompile(`-?-?~?\}\}$`)
|
|
rOpenAmp = regexp.MustCompile(`^\{\{~?&`)
|
|
)
|
|
|
|
// new instanciates a new parser
|
|
func new(input string) *parser {
|
|
return &parser{
|
|
lex: lexer.Scan(input),
|
|
}
|
|
}
|
|
|
|
// Parse analyzes given input and returns the AST root node.
|
|
func Parse(input string) (result *ast.Program, err error) {
|
|
// recover error
|
|
defer errRecover(&err)
|
|
|
|
parser := new(input)
|
|
|
|
// parse
|
|
result = parser.parseProgram()
|
|
|
|
// check last token
|
|
token := parser.shift()
|
|
if token.Kind != lexer.TokenEOF {
|
|
// Parsing ended before EOF
|
|
errToken(token, "Syntax error")
|
|
}
|
|
|
|
// fix whitespaces
|
|
processWhitespaces(result)
|
|
|
|
// named returned values
|
|
return
|
|
}
|
|
|
|
// errRecover recovers parsing panic
|
|
func errRecover(errp *error) {
|
|
e := recover()
|
|
if e != nil {
|
|
switch err := e.(type) {
|
|
case runtime.Error:
|
|
panic(e)
|
|
case error:
|
|
*errp = err
|
|
default:
|
|
panic(e)
|
|
}
|
|
}
|
|
}
|
|
|
|
// errPanic panics
|
|
func errPanic(err error, line int) {
|
|
panic(fmt.Errorf("Parse error on line %d:\n%s", line, err))
|
|
}
|
|
|
|
// errNode panics with given node infos
|
|
func errNode(node ast.Node, msg string) {
|
|
errPanic(fmt.Errorf("%s\nNode: %s", msg, node), node.Location().Line)
|
|
}
|
|
|
|
// errNode panics with given Token infos
|
|
func errToken(tok *lexer.Token, msg string) {
|
|
errPanic(fmt.Errorf("%s\nToken: %s", msg, tok), tok.Line)
|
|
}
|
|
|
|
// errNode panics because of an unexpected Token kind
|
|
func errExpected(expect lexer.TokenKind, tok *lexer.Token) {
|
|
errPanic(fmt.Errorf("Expecting %s, got: '%s'", expect, tok), tok.Line)
|
|
}
|
|
|
|
// program : statement*
|
|
func (p *parser) parseProgram() *ast.Program {
|
|
result := ast.NewProgram(p.next().Pos, p.next().Line)
|
|
|
|
for p.isStatement() {
|
|
result.AddStatement(p.parseStatement())
|
|
}
|
|
|
|
return result
|
|
}
|
|
|
|
// statement : mustache | block | rawBlock | partial | content | COMMENT
|
|
func (p *parser) parseStatement() ast.Node {
|
|
var result ast.Node
|
|
|
|
tok := p.next()
|
|
|
|
switch tok.Kind {
|
|
case lexer.TokenOpen, lexer.TokenOpenUnescaped:
|
|
// mustache
|
|
result = p.parseMustache()
|
|
case lexer.TokenOpenBlock:
|
|
// block
|
|
result = p.parseBlock()
|
|
case lexer.TokenOpenInverse:
|
|
// block
|
|
result = p.parseInverse()
|
|
case lexer.TokenOpenRawBlock:
|
|
// rawBlock
|
|
result = p.parseRawBlock()
|
|
case lexer.TokenOpenPartial:
|
|
// partial
|
|
result = p.parsePartial()
|
|
case lexer.TokenContent:
|
|
// content
|
|
result = p.parseContent()
|
|
case lexer.TokenComment:
|
|
// COMMENT
|
|
result = p.parseComment()
|
|
}
|
|
|
|
return result
|
|
}
|
|
|
|
// isStatement returns true if next token starts a statement
|
|
func (p *parser) isStatement() bool {
|
|
if !p.have(1) {
|
|
return false
|
|
}
|
|
|
|
switch p.next().Kind {
|
|
case lexer.TokenOpen, lexer.TokenOpenUnescaped, lexer.TokenOpenBlock,
|
|
lexer.TokenOpenInverse, lexer.TokenOpenRawBlock, lexer.TokenOpenPartial,
|
|
lexer.TokenContent, lexer.TokenComment:
|
|
return true
|
|
}
|
|
|
|
return false
|
|
}
|
|
|
|
// content : CONTENT
|
|
func (p *parser) parseContent() *ast.ContentStatement {
|
|
// CONTENT
|
|
tok := p.shift()
|
|
if tok.Kind != lexer.TokenContent {
|
|
// @todo This check can be removed if content is optional in a raw block
|
|
errExpected(lexer.TokenContent, tok)
|
|
}
|
|
|
|
return ast.NewContentStatement(tok.Pos, tok.Line, tok.Val)
|
|
}
|
|
|
|
// COMMENT
|
|
func (p *parser) parseComment() *ast.CommentStatement {
|
|
// COMMENT
|
|
tok := p.shift()
|
|
|
|
value := rOpenComment.ReplaceAllString(tok.Val, "")
|
|
value = rCloseComment.ReplaceAllString(value, "")
|
|
|
|
result := ast.NewCommentStatement(tok.Pos, tok.Line, value)
|
|
result.Strip = ast.NewStripForStr(tok.Val)
|
|
|
|
return result
|
|
}
|
|
|
|
// param* hash?
|
|
func (p *parser) parseExpressionParamsHash() ([]ast.Node, *ast.Hash) {
|
|
var params []ast.Node
|
|
var hash *ast.Hash
|
|
|
|
// params*
|
|
if p.isParam() {
|
|
params = p.parseParams()
|
|
}
|
|
|
|
// hash?
|
|
if p.isHashSegment() {
|
|
hash = p.parseHash()
|
|
}
|
|
|
|
return params, hash
|
|
}
|
|
|
|
// helperName param* hash?
|
|
func (p *parser) parseExpression(tok *lexer.Token) *ast.Expression {
|
|
result := ast.NewExpression(tok.Pos, tok.Line)
|
|
|
|
// helperName
|
|
result.Path = p.parseHelperName()
|
|
|
|
// param* hash?
|
|
result.Params, result.Hash = p.parseExpressionParamsHash()
|
|
|
|
return result
|
|
}
|
|
|
|
// rawBlock : openRawBlock content endRawBlock
|
|
// openRawBlock : OPEN_RAW_BLOCK helperName param* hash? CLOSE_RAW_BLOCK
|
|
// endRawBlock : OPEN_END_RAW_BLOCK helperName CLOSE_RAW_BLOCK
|
|
func (p *parser) parseRawBlock() *ast.BlockStatement {
|
|
// OPEN_RAW_BLOCK
|
|
tok := p.shift()
|
|
|
|
result := ast.NewBlockStatement(tok.Pos, tok.Line)
|
|
|
|
// helperName param* hash?
|
|
result.Expression = p.parseExpression(tok)
|
|
|
|
openName := result.Expression.Canonical()
|
|
|
|
// CLOSE_RAW_BLOCK
|
|
tok = p.shift()
|
|
if tok.Kind != lexer.TokenCloseRawBlock {
|
|
errExpected(lexer.TokenCloseRawBlock, tok)
|
|
}
|
|
|
|
// content
|
|
// @todo Is content mandatory in a raw block ?
|
|
content := p.parseContent()
|
|
|
|
program := ast.NewProgram(tok.Pos, tok.Line)
|
|
program.AddStatement(content)
|
|
|
|
result.Program = program
|
|
|
|
// OPEN_END_RAW_BLOCK
|
|
tok = p.shift()
|
|
if tok.Kind != lexer.TokenOpenEndRawBlock {
|
|
// should never happen as it is caught by lexer
|
|
errExpected(lexer.TokenOpenEndRawBlock, tok)
|
|
}
|
|
|
|
// helperName
|
|
endID := p.parseHelperName()
|
|
|
|
closeName, ok := ast.HelperNameStr(endID)
|
|
if !ok {
|
|
errNode(endID, "Erroneous closing expression")
|
|
}
|
|
|
|
if openName != closeName {
|
|
errNode(endID, fmt.Sprintf("%s doesn't match %s", openName, closeName))
|
|
}
|
|
|
|
// CLOSE_RAW_BLOCK
|
|
tok = p.shift()
|
|
if tok.Kind != lexer.TokenCloseRawBlock {
|
|
errExpected(lexer.TokenCloseRawBlock, tok)
|
|
}
|
|
|
|
return result
|
|
}
|
|
|
|
// block : openBlock program inverseChain? closeBlock
|
|
func (p *parser) parseBlock() *ast.BlockStatement {
|
|
// openBlock
|
|
result, blockParams := p.parseOpenBlock()
|
|
|
|
// program
|
|
program := p.parseProgram()
|
|
program.BlockParams = blockParams
|
|
result.Program = program
|
|
|
|
// inverseChain?
|
|
if p.isInverseChain() {
|
|
result.Inverse = p.parseInverseChain()
|
|
}
|
|
|
|
// closeBlock
|
|
p.parseCloseBlock(result)
|
|
|
|
setBlockInverseStrip(result)
|
|
|
|
return result
|
|
}
|
|
|
|
// setBlockInverseStrip is called when parsing `block` (openBlock | openInverse) and `inverseChain`
|
|
//
|
|
// TODO: This was totally cargo culted ! CHECK THAT !
|
|
//
|
|
// cf. prepareBlock() in:
|
|
// https://github.com/wycats/handlebars.js/blob/master/lib/handlebars/compiler/helper.js
|
|
func setBlockInverseStrip(block *ast.BlockStatement) {
|
|
if block.Inverse == nil {
|
|
return
|
|
}
|
|
|
|
if block.Inverse.Chained {
|
|
b, _ := block.Inverse.Body[0].(*ast.BlockStatement)
|
|
b.CloseStrip = block.CloseStrip
|
|
}
|
|
|
|
block.InverseStrip = block.Inverse.Strip
|
|
}
|
|
|
|
// block : openInverse program inverseAndProgram? closeBlock
|
|
func (p *parser) parseInverse() *ast.BlockStatement {
|
|
// openInverse
|
|
result, blockParams := p.parseOpenBlock()
|
|
|
|
// program
|
|
program := p.parseProgram()
|
|
|
|
program.BlockParams = blockParams
|
|
result.Inverse = program
|
|
|
|
// inverseAndProgram?
|
|
if p.isInverse() {
|
|
result.Program = p.parseInverseAndProgram()
|
|
}
|
|
|
|
// closeBlock
|
|
p.parseCloseBlock(result)
|
|
|
|
setBlockInverseStrip(result)
|
|
|
|
return result
|
|
}
|
|
|
|
// helperName param* hash? blockParams?
|
|
func (p *parser) parseOpenBlockExpression(tok *lexer.Token) (*ast.BlockStatement, []string) {
|
|
var blockParams []string
|
|
|
|
result := ast.NewBlockStatement(tok.Pos, tok.Line)
|
|
|
|
// helperName param* hash?
|
|
result.Expression = p.parseExpression(tok)
|
|
|
|
// blockParams?
|
|
if p.isBlockParams() {
|
|
blockParams = p.parseBlockParams()
|
|
}
|
|
|
|
// named returned values
|
|
return result, blockParams
|
|
}
|
|
|
|
// inverseChain : openInverseChain program inverseChain?
|
|
// | inverseAndProgram
|
|
func (p *parser) parseInverseChain() *ast.Program {
|
|
if p.isInverse() {
|
|
// inverseAndProgram
|
|
return p.parseInverseAndProgram()
|
|
}
|
|
|
|
result := ast.NewProgram(p.next().Pos, p.next().Line)
|
|
|
|
// openInverseChain
|
|
block, blockParams := p.parseOpenBlock()
|
|
|
|
// program
|
|
program := p.parseProgram()
|
|
|
|
program.BlockParams = blockParams
|
|
block.Program = program
|
|
|
|
// inverseChain?
|
|
if p.isInverseChain() {
|
|
block.Inverse = p.parseInverseChain()
|
|
}
|
|
|
|
setBlockInverseStrip(block)
|
|
|
|
result.Chained = true
|
|
result.AddStatement(block)
|
|
|
|
return result
|
|
}
|
|
|
|
// Returns true if current token starts an inverse chain
|
|
func (p *parser) isInverseChain() bool {
|
|
return p.isOpenInverseChain() || p.isInverse()
|
|
}
|
|
|
|
// inverseAndProgram : INVERSE program
|
|
func (p *parser) parseInverseAndProgram() *ast.Program {
|
|
// INVERSE
|
|
tok := p.shift()
|
|
|
|
// program
|
|
result := p.parseProgram()
|
|
result.Strip = ast.NewStripForStr(tok.Val)
|
|
|
|
return result
|
|
}
|
|
|
|
// openBlock : OPEN_BLOCK helperName param* hash? blockParams? CLOSE
|
|
// openInverse : OPEN_INVERSE helperName param* hash? blockParams? CLOSE
|
|
// openInverseChain: OPEN_INVERSE_CHAIN helperName param* hash? blockParams? CLOSE
|
|
func (p *parser) parseOpenBlock() (*ast.BlockStatement, []string) {
|
|
// OPEN_BLOCK | OPEN_INVERSE | OPEN_INVERSE_CHAIN
|
|
tok := p.shift()
|
|
|
|
// helperName param* hash? blockParams?
|
|
result, blockParams := p.parseOpenBlockExpression(tok)
|
|
|
|
// CLOSE
|
|
tokClose := p.shift()
|
|
if tokClose.Kind != lexer.TokenClose {
|
|
errExpected(lexer.TokenClose, tokClose)
|
|
}
|
|
|
|
result.OpenStrip = ast.NewStrip(tok.Val, tokClose.Val)
|
|
|
|
// named returned values
|
|
return result, blockParams
|
|
}
|
|
|
|
// closeBlock : OPEN_ENDBLOCK helperName CLOSE
|
|
func (p *parser) parseCloseBlock(block *ast.BlockStatement) {
|
|
// OPEN_ENDBLOCK
|
|
tok := p.shift()
|
|
if tok.Kind != lexer.TokenOpenEndBlock {
|
|
errExpected(lexer.TokenOpenEndBlock, tok)
|
|
}
|
|
|
|
// helperName
|
|
endID := p.parseHelperName()
|
|
|
|
closeName, ok := ast.HelperNameStr(endID)
|
|
if !ok {
|
|
errNode(endID, "Erroneous closing expression")
|
|
}
|
|
|
|
openName := block.Expression.Canonical()
|
|
if openName != closeName {
|
|
errNode(endID, fmt.Sprintf("%s doesn't match %s", openName, closeName))
|
|
}
|
|
|
|
// CLOSE
|
|
tokClose := p.shift()
|
|
if tokClose.Kind != lexer.TokenClose {
|
|
errExpected(lexer.TokenClose, tokClose)
|
|
}
|
|
|
|
block.CloseStrip = ast.NewStrip(tok.Val, tokClose.Val)
|
|
}
|
|
|
|
// mustache : OPEN helperName param* hash? CLOSE
|
|
// | OPEN_UNESCAPED helperName param* hash? CLOSE_UNESCAPED
|
|
func (p *parser) parseMustache() *ast.MustacheStatement {
|
|
// OPEN | OPEN_UNESCAPED
|
|
tok := p.shift()
|
|
|
|
closeToken := lexer.TokenClose
|
|
if tok.Kind == lexer.TokenOpenUnescaped {
|
|
closeToken = lexer.TokenCloseUnescaped
|
|
}
|
|
|
|
unescaped := false
|
|
if (tok.Kind == lexer.TokenOpenUnescaped) || (rOpenAmp.MatchString(tok.Val)) {
|
|
unescaped = true
|
|
}
|
|
|
|
result := ast.NewMustacheStatement(tok.Pos, tok.Line, unescaped)
|
|
|
|
// helperName param* hash?
|
|
result.Expression = p.parseExpression(tok)
|
|
|
|
// CLOSE | CLOSE_UNESCAPED
|
|
tokClose := p.shift()
|
|
if tokClose.Kind != closeToken {
|
|
errExpected(closeToken, tokClose)
|
|
}
|
|
|
|
result.Strip = ast.NewStrip(tok.Val, tokClose.Val)
|
|
|
|
return result
|
|
}
|
|
|
|
// partial : OPEN_PARTIAL partialName param* hash? CLOSE
|
|
func (p *parser) parsePartial() *ast.PartialStatement {
|
|
// OPEN_PARTIAL
|
|
tok := p.shift()
|
|
|
|
result := ast.NewPartialStatement(tok.Pos, tok.Line)
|
|
|
|
// partialName
|
|
result.Name = p.parsePartialName()
|
|
|
|
// param* hash?
|
|
result.Params, result.Hash = p.parseExpressionParamsHash()
|
|
|
|
// CLOSE
|
|
tokClose := p.shift()
|
|
if tokClose.Kind != lexer.TokenClose {
|
|
errExpected(lexer.TokenClose, tokClose)
|
|
}
|
|
|
|
result.Strip = ast.NewStrip(tok.Val, tokClose.Val)
|
|
|
|
return result
|
|
}
|
|
|
|
// helperName | sexpr
|
|
func (p *parser) parseHelperNameOrSexpr() ast.Node {
|
|
if p.isSexpr() {
|
|
// sexpr
|
|
return p.parseSexpr()
|
|
}
|
|
|
|
// helperName
|
|
return p.parseHelperName()
|
|
}
|
|
|
|
// param : helperName | sexpr
|
|
func (p *parser) parseParam() ast.Node {
|
|
return p.parseHelperNameOrSexpr()
|
|
}
|
|
|
|
// Returns true if next tokens represent a `param`
|
|
func (p *parser) isParam() bool {
|
|
return (p.isSexpr() || p.isHelperName()) && !p.isHashSegment()
|
|
}
|
|
|
|
// param*
|
|
func (p *parser) parseParams() []ast.Node {
|
|
var result []ast.Node
|
|
|
|
for p.isParam() {
|
|
result = append(result, p.parseParam())
|
|
}
|
|
|
|
return result
|
|
}
|
|
|
|
// sexpr : OPEN_SEXPR helperName param* hash? CLOSE_SEXPR
|
|
func (p *parser) parseSexpr() *ast.SubExpression {
|
|
// OPEN_SEXPR
|
|
tok := p.shift()
|
|
|
|
result := ast.NewSubExpression(tok.Pos, tok.Line)
|
|
|
|
// helperName param* hash?
|
|
result.Expression = p.parseExpression(tok)
|
|
|
|
// CLOSE_SEXPR
|
|
tok = p.shift()
|
|
if tok.Kind != lexer.TokenCloseSexpr {
|
|
errExpected(lexer.TokenCloseSexpr, tok)
|
|
}
|
|
|
|
return result
|
|
}
|
|
|
|
// hash : hashSegment+
|
|
func (p *parser) parseHash() *ast.Hash {
|
|
var pairs []*ast.HashPair
|
|
|
|
for p.isHashSegment() {
|
|
pairs = append(pairs, p.parseHashSegment())
|
|
}
|
|
|
|
firstLoc := pairs[0].Location()
|
|
|
|
result := ast.NewHash(firstLoc.Pos, firstLoc.Line)
|
|
result.Pairs = pairs
|
|
|
|
return result
|
|
}
|
|
|
|
// returns true if next tokens represents a `hashSegment`
|
|
func (p *parser) isHashSegment() bool {
|
|
return p.have(2) && (p.next().Kind == lexer.TokenID) && (p.nextAt(1).Kind == lexer.TokenEquals)
|
|
}
|
|
|
|
// hashSegment : ID EQUALS param
|
|
func (p *parser) parseHashSegment() *ast.HashPair {
|
|
// ID
|
|
tok := p.shift()
|
|
|
|
// EQUALS
|
|
p.shift()
|
|
|
|
// param
|
|
param := p.parseParam()
|
|
|
|
result := ast.NewHashPair(tok.Pos, tok.Line)
|
|
result.Key = tok.Val
|
|
result.Val = param
|
|
|
|
return result
|
|
}
|
|
|
|
// blockParams : OPEN_BLOCK_PARAMS ID+ CLOSE_BLOCK_PARAMS
|
|
func (p *parser) parseBlockParams() []string {
|
|
var result []string
|
|
|
|
// OPEN_BLOCK_PARAMS
|
|
tok := p.shift()
|
|
|
|
// ID+
|
|
for p.isID() {
|
|
result = append(result, p.shift().Val)
|
|
}
|
|
|
|
if len(result) == 0 {
|
|
errExpected(lexer.TokenID, p.next())
|
|
}
|
|
|
|
// CLOSE_BLOCK_PARAMS
|
|
tok = p.shift()
|
|
if tok.Kind != lexer.TokenCloseBlockParams {
|
|
errExpected(lexer.TokenCloseBlockParams, tok)
|
|
}
|
|
|
|
return result
|
|
}
|
|
|
|
// helperName : path | dataName | STRING | NUMBER | BOOLEAN | UNDEFINED | NULL
|
|
func (p *parser) parseHelperName() ast.Node {
|
|
var result ast.Node
|
|
|
|
tok := p.next()
|
|
|
|
switch tok.Kind {
|
|
case lexer.TokenBoolean:
|
|
// BOOLEAN
|
|
p.shift()
|
|
result = ast.NewBooleanLiteral(tok.Pos, tok.Line, (tok.Val == "true"), tok.Val)
|
|
case lexer.TokenNumber:
|
|
// NUMBER
|
|
p.shift()
|
|
|
|
val, isInt := parseNumber(tok)
|
|
result = ast.NewNumberLiteral(tok.Pos, tok.Line, val, isInt, tok.Val)
|
|
case lexer.TokenString:
|
|
// STRING
|
|
p.shift()
|
|
result = ast.NewStringLiteral(tok.Pos, tok.Line, tok.Val)
|
|
case lexer.TokenData:
|
|
// dataName
|
|
result = p.parseDataName()
|
|
default:
|
|
// path
|
|
result = p.parsePath(false)
|
|
}
|
|
|
|
return result
|
|
}
|
|
|
|
// parseNumber parses a number
|
|
func parseNumber(tok *lexer.Token) (result float64, isInt bool) {
|
|
var valInt int
|
|
var err error
|
|
|
|
valInt, err = strconv.Atoi(tok.Val)
|
|
if err == nil {
|
|
isInt = true
|
|
|
|
result = float64(valInt)
|
|
} else {
|
|
isInt = false
|
|
|
|
result, err = strconv.ParseFloat(tok.Val, 64)
|
|
if err != nil {
|
|
errToken(tok, fmt.Sprintf("Failed to parse number: %s", tok.Val))
|
|
}
|
|
}
|
|
|
|
// named returned values
|
|
return
|
|
}
|
|
|
|
// Returns true if next tokens represent a `helperName`
|
|
func (p *parser) isHelperName() bool {
|
|
switch p.next().Kind {
|
|
case lexer.TokenBoolean, lexer.TokenNumber, lexer.TokenString, lexer.TokenData, lexer.TokenID:
|
|
return true
|
|
}
|
|
|
|
return false
|
|
}
|
|
|
|
// partialName : helperName | sexpr
|
|
func (p *parser) parsePartialName() ast.Node {
|
|
return p.parseHelperNameOrSexpr()
|
|
}
|
|
|
|
// dataName : DATA pathSegments
|
|
func (p *parser) parseDataName() *ast.PathExpression {
|
|
// DATA
|
|
p.shift()
|
|
|
|
// pathSegments
|
|
return p.parsePath(true)
|
|
}
|
|
|
|
// path : pathSegments
|
|
// pathSegments : pathSegments SEP ID
|
|
// | ID
|
|
func (p *parser) parsePath(data bool) *ast.PathExpression {
|
|
var tok *lexer.Token
|
|
|
|
// ID
|
|
tok = p.shift()
|
|
if tok.Kind != lexer.TokenID {
|
|
errExpected(lexer.TokenID, tok)
|
|
}
|
|
|
|
result := ast.NewPathExpression(tok.Pos, tok.Line, data)
|
|
result.Part(tok.Val)
|
|
|
|
for p.isPathSep() {
|
|
// SEP
|
|
tok = p.shift()
|
|
result.Sep(tok.Val)
|
|
|
|
// ID
|
|
tok = p.shift()
|
|
if tok.Kind != lexer.TokenID {
|
|
errExpected(lexer.TokenID, tok)
|
|
}
|
|
|
|
result.Part(tok.Val)
|
|
|
|
if len(result.Parts) > 0 {
|
|
switch tok.Val {
|
|
case "..", ".", "this":
|
|
errToken(tok, "Invalid path: "+result.Original)
|
|
}
|
|
}
|
|
}
|
|
|
|
return result
|
|
}
|
|
|
|
// Ensures there is token to parse at given index
|
|
func (p *parser) ensure(index int) {
|
|
if p.lexOver {
|
|
// nothing more to grab
|
|
return
|
|
}
|
|
|
|
nb := index + 1
|
|
|
|
for len(p.tokens) < nb {
|
|
// fetch next token
|
|
tok := p.lex.NextToken()
|
|
|
|
// queue it
|
|
p.tokens = append(p.tokens, &tok)
|
|
|
|
if (tok.Kind == lexer.TokenEOF) || (tok.Kind == lexer.TokenError) {
|
|
p.lexOver = true
|
|
break
|
|
}
|
|
}
|
|
}
|
|
|
|
// have returns true is there are a list given number of tokens to consume left
|
|
func (p *parser) have(nb int) bool {
|
|
p.ensure(nb - 1)
|
|
|
|
return len(p.tokens) >= nb
|
|
}
|
|
|
|
// nextAt returns next token at given index, without consuming it
|
|
func (p *parser) nextAt(index int) *lexer.Token {
|
|
p.ensure(index)
|
|
|
|
return p.tokens[index]
|
|
}
|
|
|
|
// next returns next token without consuming it
|
|
func (p *parser) next() *lexer.Token {
|
|
return p.nextAt(0)
|
|
}
|
|
|
|
// shift returns next token and remove it from the tokens buffer
|
|
//
|
|
// Panics if next token is `TokenError`
|
|
func (p *parser) shift() *lexer.Token {
|
|
var result *lexer.Token
|
|
|
|
p.ensure(0)
|
|
|
|
result, p.tokens = p.tokens[0], p.tokens[1:]
|
|
|
|
// check error token
|
|
if result.Kind == lexer.TokenError {
|
|
errToken(result, "Lexer error")
|
|
}
|
|
|
|
return result
|
|
}
|
|
|
|
// isToken returns true if next token is of given type
|
|
func (p *parser) isToken(kind lexer.TokenKind) bool {
|
|
return p.have(1) && p.next().Kind == kind
|
|
}
|
|
|
|
// isSexpr returns true if next token starts a sexpr
|
|
func (p *parser) isSexpr() bool {
|
|
return p.isToken(lexer.TokenOpenSexpr)
|
|
}
|
|
|
|
// isPathSep returns true if next token is a path separator
|
|
func (p *parser) isPathSep() bool {
|
|
return p.isToken(lexer.TokenSep)
|
|
}
|
|
|
|
// isID returns true if next token is an ID
|
|
func (p *parser) isID() bool {
|
|
return p.isToken(lexer.TokenID)
|
|
}
|
|
|
|
// isBlockParams returns true if next token starts a block params
|
|
func (p *parser) isBlockParams() bool {
|
|
return p.isToken(lexer.TokenOpenBlockParams)
|
|
}
|
|
|
|
// isInverse returns true if next token starts an INVERSE sequence
|
|
func (p *parser) isInverse() bool {
|
|
return p.isToken(lexer.TokenInverse)
|
|
}
|
|
|
|
// isOpenInverseChain returns true if next token is OPEN_INVERSE_CHAIN
|
|
func (p *parser) isOpenInverseChain() bool {
|
|
return p.isToken(lexer.TokenOpenInverseChain)
|
|
}
|