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// See LICENSE for licensing information

package syntax

import (

"bytes"

"fmt"

"io"

"strconv"

"strings"

"unicode/utf8"

)

// ParserOption is a function which can be passed to NewParser

// to alter its behavior. To apply option to existing Parser

// call it directly, for example KeepComments(true)(parser).

type ParserOption func(*Parser)

// KeepComments makes the parser parse comments and attach them to

// nodes, as opposed to discarding them.

func KeepComments(enabled bool) ParserOption {

return func(p *Parser) { p.keepComments = enabled }

}

// LangVariant describes a shell language variant to use when tokenizing and

// parsing shell code. The zero value is LangBash.

type LangVariant int

const (

// LangBash corresponds to the GNU Bash language, as described in its

// manual at https://www.gnu.org/software/bash/manual/bash.html.

// We currently follow Bash version 5.1.

// Its string representation is "bash".

LangBash LangVariant = iota

// LangPOSIX corresponds to the POSIX Shell language, as described at

// https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html.

// Its string representation is "posix" or "sh".

LangPOSIX

// LangMirBSDKorn corresponds to the MirBSD Korn Shell, also known as

// mksh, as described at http://www.mirbsd.org/htman/i386/man1/mksh.htm.

// Note that it shares some features with Bash, due to the the shared

// ancestry that is ksh.

// We currently follow mksh version 59.

// Its string representation is "mksh".

LangMirBSDKorn

// LangBats corresponds to the Bash Automated Testing System language,

// as described at https://github.com/bats-core/bats-core. Note that

// it's just a small extension of the Bash language.

// Its string representation is "bats".

LangBats

// LangAuto corresponds to automatic language detection,

// commonly used by end-user applications like shfmt,

// which can guess a file's language variant given its filename or shebang.

// At this time, the Parser does not support LangAuto.

LangAuto

)

// Variant changes the shell language variant that the parser will

// accept.

// The passed language variant must be one of the constant values defined in

// this package.

func Variant(l LangVariant) ParserOption {

switch l {

case LangBash, LangPOSIX, LangMirBSDKorn, LangBats:

case LangAuto:

panic("LangAuto is not supported by the parser at this time")

default:

panic(fmt.Sprintf("unknown shell language variant: %d", l))

}

return func(p *Parser) { p.lang = l }

}

func (l LangVariant) String() string {

switch l {

case LangBash:

return "bash"

case LangPOSIX:

return "posix"

case LangMirBSDKorn:

return "mksh"

case LangBats:

return "bats"

case LangAuto:

return "auto"

}

return "unknown shell language variant"

}

func (l *LangVariant) Set(s string) error {

switch s {

case "bash":

*l = LangBash

case "posix", "sh":

*l = LangPOSIX

case "mksh":

*l = LangMirBSDKorn

case "bats":

*l = LangBats

case "auto":

*l = LangAuto

default:

return fmt.Errorf("unknown shell language variant: %q", s)

}

return nil

}

func (l LangVariant) isBash() bool {

return l == LangBash || l == LangBats

}

// StopAt configures the lexer to stop at an arbitrary word, treating it

// as if it were the end of the input. It can contain any characters

// except whitespace, and cannot be over four bytes in size.

// This can be useful to embed shell code within another language, as

// one can use a special word to mark the delimiters between the two.

// As a word, it will only apply when following whitespace or a

// separating token. For example, StopAt("$$") will act on the inputs

// "foo $$" and "foo;$$", but not on "foo '$$'".

// The match is done by prefix, so the example above will also act on

// "foo $$bar".

func StopAt(word string) ParserOption {

if len(word) > 4 {

panic("stop word can't be over four bytes in size")

}

if strings.ContainsAny(word, " \t\n\r") {

panic("stop word can't contain whitespace characters")

}

return func(p *Parser) { p.stopAt = []byte(word) }

}

// NewParser allocates a new Parser and applies any number of options.

func NewParser(options ...ParserOption) *Parser {

p := &Parser{}

for _, opt := range options {

opt(p)

}

return p

}

// Parse reads and parses a shell program with an optional name. It

// returns the parsed program if no issues were encountered. Otherwise,

// an error is returned. Reads from r are buffered.

// Parse can be called more than once, but not concurrently. That is, a

// Parser can be reused once it is done working.

func (p *Parser) Parse(r io.Reader, name string) (*File, error) {

p.reset()

p.f = &File{Name: name}

p.src = r

p.rune()

p.next()

p.f.Stmts, p.f.Last = p.stmtList()

if p.err == nil {

// EOF immediately after heredoc word so no newline to

// trigger it

p.doHeredocs()

}

return p.f, p.err

}

// Stmts reads and parses statements one at a time, calling a function

// each time one is parsed. If the function returns false, parsing is

// stopped and the function is not called again.

func (p *Parser) Stmts(r io.Reader, fn func(*Stmt) bool) error {

p.reset()

p.f = &File{}

p.src = r

p.rune()

p.next()

p.stmts(fn)

if p.err == nil {

// EOF immediately after heredoc word so no newline to

// trigger it

p.doHeredocs()

}

return p.err

}

type wrappedReader struct {

*Parser

io.Reader

lastLine int

accumulated []*Stmt

fn func([]*Stmt) bool

}

func (w *wrappedReader) Read(p []byte) (n int, err error) {

// If we lexed a newline for the first time, we just finished a line, so

// we may need to give a callback for the edge cases below not covered

// by Parser.Stmts.

if (w.r == '\n' || w.r == escNewl) && w.line > w.lastLine {

if w.Incomplete() {

// Incomplete statement; call back to print "> ".

if !w.fn(w.accumulated) {

return 0, io.EOF

}

} else if len(w.accumulated) == 0 {

// Nothing was parsed; call back to print another "$ ".

if !w.fn(nil) {

return 0, io.EOF

}

w.lastLine = w.line

}

return w.Reader.Read(p)

}

// Interactive implements what is necessary to parse statements in an

// interactive shell. The parser will call the given function under two

// circumstances outlined below.

// If a line containing any number of statements is parsed, the function will be

// called with said statements.

// If a line ending in an incomplete statement is parsed, the function will be

// called with any fully parsed statements, and [Parser.Incomplete] will return true.

// One can imagine a simple interactive shell implementation as follows:

// fmt.Fprintf(os.Stdout, "$ ")

// parser.Interactive(os.Stdin, func(stmts []*syntax.Stmt) bool {

// if parser.Incomplete() {

// fmt.Fprintf(os.Stdout, "> ")

// return true

// }

// run(stmts)

// fmt.Fprintf(os.Stdout, "$ ")

// return true

// }

// If the callback function returns false, parsing is stopped and the function

// is not called again.

func (p *Parser) Interactive(r io.Reader, fn func([]*Stmt) bool) error {

w := wrappedReader{Parser: p, Reader: r, fn: fn}

return p.Stmts(&w, func(stmt *Stmt) bool {

w.accumulated = append(w.accumulated, stmt)

// We finished parsing a statement and we're at a newline token,

// so we finished fully parsing a number of statements. Call

// back to run the statements and print "$ ".

if p.tok == _Newl {

if !fn(w.accumulated) {

return false

}

w.accumulated = w.accumulated[:0]

// The callback above would already print "$ ", so we

// don't want the subsequent wrappedReader.Read to cause

// another "$ " print thinking that nothing was parsed.

w.lastLine = w.line + 1

}

return true

})

}

// Words reads and parses words one at a time, calling a function each time one

// is parsed. If the function returns false, parsing is stopped and the function

// is not called again.

// Newlines are skipped, meaning that multi-line input will work fine. If the

// parser encounters a token that isn't a word, such as a semicolon, an error

// will be returned.

// Note that the lexer doesn't currently tokenize spaces, so it may need to read

// a non-space byte such as a newline or a letter before finishing the parsing

// of a word. This will be fixed in the future.

func (p *Parser) Words(r io.Reader, fn func(*Word) bool) error {

p.reset()

p.f = &File{}

p.src = r

p.rune()

p.next()

for {

p.got(_Newl)

w := p.getWord()

if w == nil {

if p.tok != _EOF {

p.curErr("%s is not a valid word", p.tok)

}

return p.err

}

if !fn(w) {

return nil

}

// Document parses a single here-document word. That is, it parses the input as

// if they were lines following a <<EOF redirection.

// In practice, this is the same as parsing the input as if it were within

// double quotes, but without having to escape all double quote characters.

// Similarly, the here-document word parsed here cannot be ended by any

// delimiter other than reaching the end of the input.

func (p *Parser) Document(r io.Reader) (*Word, error) {

p.reset()

p.f = &File{}

p.src = r

p.rune()

p.quote = hdocBody

p.hdocStops = [][]byte{[]byte("MVDAN_CC_SH_SYNTAX_EOF")}

p.parsingDoc = true

p.next()

w := p.getWord()

return w, p.err

}

// Arithmetic parses a single arithmetic expression. That is, as if the input

// were within the $(( and )) tokens.

func (p *Parser) Arithmetic(r io.Reader) (ArithmExpr, error) {

p.reset()

p.f = &File{}

p.src = r

p.rune()

p.quote = arithmExpr

p.next()

expr := p.arithmExpr(false)

return expr, p.err

}

// Parser holds the internal state of the parsing mechanism of a

// program.

type Parser struct {

src io.Reader

bs []byte // current chunk of read bytes

bsp int // pos within chunk for the rune after r

r rune // next rune

w int // width of r

f *File

spaced bool // whether tok has whitespace on its left

err error // lexer/parser error

readErr error // got a read error, but bytes left

tok token // current token

val string // current value (valid if tok is _Lit*)

// position of r, to be converted to Parser.pos later

offs, line, col int

pos Pos // position of tok

// TODO: Guard against offset overflow too. Less likely as it's 32-bit,

// whereas line and col are 16-bit.

lineOverflow bool

colOverflow bool

quote quoteState // current lexer state

eqlOffs int // position of '=' in val (a literal)

keepComments bool

lang LangVariant

stopAt []byte

forbidNested bool

// list of pending heredoc bodies

buriedHdocs int

heredocs []*Redirect

hdocStops [][]byte // stack of end words for open heredocs

parsingDoc bool // true if using Parser.Document

// openStmts is how many entire statements we're currently parsing. A

// non-zero number means that we require certain tokens or words before

// reaching EOF.

openStmts int

// openBquotes is how many levels of backquotes are open at the moment.

openBquotes int

// lastBquoteEsc is how many times the last backquote token was escaped

lastBquoteEsc int

// buriedBquotes is like openBquotes, but saved for when the parser

// comes out of single quotes

buriedBquotes int

rxOpenParens int

rxFirstPart bool

accComs []Comment

curComs *[]Comment

litBatch []Lit

wordBatch []wordAlloc

stmtBatch []Stmt

callBatch []callAlloc

readBuf [bufSize]byte

litBuf [bufSize]byte

litBs []byte

}

// Incomplete reports whether the parser is waiting to read more bytes because

// it needs to finish properly parsing a statement.

// It is only safe to call while the parser is blocked on a read. For an example

// use case, see [Parser.Interactive].

func (p *Parser) Incomplete() bool {

// If we're in a quote state other than noState, we're parsing a node

// such as a double-quoted string.

// If there are any open statements, we need to finish them.

// If we're constructing a literal, we need to finish it.

return p.quote != noState || p.openStmts > 0 || p.litBs != nil

}

const bufSize = 1 << 10

func (p *Parser) reset() {

p.tok, p.val = illegalTok, ""

p.eqlOffs = 0

p.bs, p.bsp = nil, 0

p.offs, p.line, p.col = 0, 1, 1

p.r, p.w = 0, 0

p.err, p.readErr = nil, nil

p.quote, p.forbidNested = noState, false

p.openStmts = 0

p.heredocs, p.buriedHdocs = p.heredocs[:0], 0

p.parsingDoc = false

p.openBquotes, p.buriedBquotes = 0, 0

p.accComs, p.curComs = nil, &p.accComs

p.litBatch = nil

p.wordBatch = nil

p.stmtBatch = nil

p.callBatch = nil

}

func (p *Parser) nextPos() Pos {

// TODO: detect offset overflow while lexing as well.

var line, col uint

if !p.lineOverflow {

line = uint(p.line)

}

if !p.colOverflow {

col = uint(p.col)

}

return NewPos(uint(p.offs+p.bsp-p.w), line, col)

}

func (p *Parser) lit(pos Pos, val string) *Lit {

if len(p.litBatch) == 0 {

p.litBatch = make([]Lit, 64)

}

l := &p.litBatch[0]

p.litBatch = p.litBatch[1:]

l.ValuePos = pos

l.ValueEnd = p.nextPos()

l.Value = val

return l

}

type wordAlloc struct {

word Word

parts [1]WordPart

}

func (p *Parser) wordAnyNumber() *Word {

if len(p.wordBatch) == 0 {

p.wordBatch = make([]wordAlloc, 32)

}

alloc := &p.wordBatch[0]

p.wordBatch = p.wordBatch[1:]

w := &alloc.word

w.Parts = p.wordParts(alloc.parts[:0])

return w

}

func (p *Parser) wordOne(part WordPart) *Word {

if len(p.wordBatch) == 0 {

p.wordBatch = make([]wordAlloc, 32)

}

alloc := &p.wordBatch[0]

p.wordBatch = p.wordBatch[1:]

w := &alloc.word

w.Parts = alloc.parts[:1]

w.Parts[0] = part

return w

}

func (p *Parser) stmt(pos Pos) *Stmt {

if len(p.stmtBatch) == 0 {

p.stmtBatch = make([]Stmt, 32)

}

s := &p.stmtBatch[0]

p.stmtBatch = p.stmtBatch[1:]

s.Position = pos

return s

}

type callAlloc struct {

ce CallExpr

ws [4]*Word

}

func (p *Parser) call(w *Word) *CallExpr {

if len(p.callBatch) == 0 {

p.callBatch = make([]callAlloc, 32)

}

alloc := &p.callBatch[0]

p.callBatch = p.callBatch[1:]

ce := &alloc.ce

ce.Args = alloc.ws[:1]

ce.Args[0] = w

return ce

}

//go:generate stringer -type=quoteState

type quoteState uint32

const (

noState quoteState = 1 << iota

subCmd

subCmdBckquo

dblQuotes

hdocWord

hdocBody

hdocBodyTabs

arithmExpr

arithmExprLet

arithmExprCmd

arithmExprBrack

testExpr

testExprRegexp

switchCase

paramExpName

paramExpSlice

paramExpRepl

paramExpExp

arrayElems

allKeepSpaces = paramExpRepl | dblQuotes | hdocBody |

hdocBodyTabs | paramExpExp

allRegTokens = noState | subCmd | subCmdBckquo | hdocWord |

switchCase | arrayElems | testExpr

allArithmExpr = arithmExpr | arithmExprLet | arithmExprCmd |

arithmExprBrack | paramExpSlice

allParamReg = paramExpName | paramExpSlice

allParamExp = allParamReg | paramExpRepl | paramExpExp | arithmExprBrack

)

type saveState struct {

quote quoteState

buriedHdocs int

}

func (p *Parser) preNested(quote quoteState) (s saveState) {

s.quote, s.buriedHdocs = p.quote, p.buriedHdocs

p.buriedHdocs, p.quote = len(p.heredocs), quote

return

}

func (p *Parser) postNested(s saveState) {

p.quote, p.buriedHdocs = s.quote, s.buriedHdocs

}

func (p *Parser) unquotedWordBytes(w *Word) ([]byte, bool) {

buf := make([]byte, 0, 4)

didUnquote := false

for _, wp := range w.Parts {

buf, didUnquote = p.unquotedWordPart(buf, wp, false)

}

return buf, didUnquote

}

func (p *Parser) unquotedWordPart(buf []byte, wp WordPart, quotes bool) (_ []byte, quoted bool) {

switch x := wp.(type) {

case *Lit:

for i := 0; i < len(x.Value); i++ {

if b := x.Value[i]; b == '\\' && !quotes {

if i++; i < len(x.Value) {

buf = append(buf, x.Value[i])

}

quoted = true

} else {

buf = append(buf, b)

}

case *SglQuoted:

buf = append(buf, []byte(x.Value)...)

quoted = true

case *DblQuoted:

for _, wp2 := range x.Parts {

buf, _ = p.unquotedWordPart(buf, wp2, true)

}

quoted = true

}

return buf, quoted

}

func (p *Parser) doHeredocs() {

hdocs := p.heredocs[p.buriedHdocs:]

if len(hdocs) == 0 {

// Nothing do do; don't even issue a read.

return

}

p.rune() // consume '\n', since we know p.tok == _Newl

old := p.quote

p.heredocs = p.heredocs[:p.buriedHdocs]

for i, r := range hdocs {

if p.err != nil {

break

}

p.quote = hdocBody

if r.Op == DashHdoc {

p.quote = hdocBodyTabs

}

stop, quoted := p.unquotedWordBytes(r.Word)

p.hdocStops = append(p.hdocStops, stop)

if i > 0 && p.r == '\n' {

p.rune()

}

lastLine := p.line

if quoted {

r.Hdoc = p.quotedHdocWord()

} else {

p.next()

r.Hdoc = p.getWord()

}

if r.Hdoc != nil {

lastLine = int(r.Hdoc.End().Line())

}

if lastLine < p.line {

// TODO: It seems like this triggers more often than it

// should. Look into it.

l := p.lit(p.nextPos(), "")

if r.Hdoc == nil {

r.Hdoc = p.wordOne(l)

} else {

r.Hdoc.Parts = append(r.Hdoc.Parts, l)

}

if stop := p.hdocStops[len(p.hdocStops)-1]; stop != nil {

p.posErr(r.Pos(), "unclosed here-document '%s'", stop)

}

p.hdocStops = p.hdocStops[:len(p.hdocStops)-1]

}

p.quote = old

}

func (p *Parser) got(tok token) bool {

if p.tok == tok {

p.next()

return true

}

return false

}

func (p *Parser) gotRsrv(val string) (Pos, bool) {

pos := p.pos

if p.tok == _LitWord && p.val == val {

p.next()

return pos, true

}

return pos, false

}

func readableStr(s string) string {

// don't quote tokens like & or }

if s != "" && s[0] >= 'a' && s[0] <= 'z' {

return strconv.Quote(s)

}

return s

}

func (p *Parser) followErr(pos Pos, left, right string) {

leftStr := readableStr(left)

p.posErr(pos, "%s must be followed by %s", leftStr, right)

}

func (p *Parser) followErrExp(pos Pos, left string) {

p.followErr(pos, left, "an expression")

}

func (p *Parser) follow(lpos Pos, left string, tok token) {

if !p.got(tok) {

p.followErr(lpos, left, tok.String())

}

func (p *Parser) followRsrv(lpos Pos, left, val string) Pos {

pos, ok := p.gotRsrv(val)

if !ok {

p.followErr(lpos, left, fmt.Sprintf("%q", val))

}

return pos

}

func (p *Parser) followStmts(left string, lpos Pos, stops ...string) ([]*Stmt, []Comment) {

if p.got(semicolon) {

return nil, nil

}

newLine := p.got(_Newl)

stmts, last := p.stmtList(stops...)

if len(stmts) < 1 && !newLine {

p.followErr(lpos, left, "a statement list")

}

return stmts, last

}

func (p *Parser) followWordTok(tok token, pos Pos) *Word {

w := p.getWord()

if w == nil {

p.followErr(pos, tok.String(), "a word")

}

return w

}

func (p *Parser) stmtEnd(n Node, start, end string) Pos {

pos, ok := p.gotRsrv(end)

if !ok {

p.posErr(n.Pos(), "%s statement must end with %q", start, end)

}

return pos

}

func (p *Parser) quoteErr(lpos Pos, quote token) {

p.posErr(lpos, "reached %s without closing quote %s",

p.tok.String(), quote)

}

func (p *Parser) matchingErr(lpos Pos, left, right any) {

p.posErr(lpos, "reached %s without matching %s with %s",

p.tok.String(), left, right)

}

func (p *Parser) matched(lpos Pos, left, right token) Pos {

pos := p.pos

if !p.got(right) {

p.matchingErr(lpos, left, right)

}

return pos

}

func (p *Parser) errPass(err error) {

if p.err == nil {

p.err = err

p.bsp = len(p.bs) + 1

p.r = utf8.RuneSelf

p.w = 1

p.tok = _EOF

}

// IsIncomplete reports whether a Parser error could have been avoided with

// extra input bytes. For example, if an [io.EOF] was encountered while there was

// an unclosed quote or parenthesis.

func IsIncomplete(err error) bool {

perr, ok := err.(ParseError)

return ok && perr.Incomplete

}

// IsKeyword returns true if the given word is part of the language keywords.

func IsKeyword(word string) bool {

// This list has been copied from the bash 5.1 source code, file y.tab.c +4460

switch word {

case

"!",

"[[", // only if COND_COMMAND is defined

"]]", // only if COND_COMMAND is defined

"case",

"coproc", // only if COPROCESS_SUPPORT is defined

"do",

"done",

"else",

"esac",

"fi",

"for",

"function",

"if",

"in",

"select", // only if SELECT_COMMAND is defined

"then",

"time", // only if COMMAND_TIMING is defined

"until",

"while",

"{",

"}":

return true

}

return false

}

// ParseError represents an error found when parsing a source file, from which

// the parser cannot recover.

type ParseError struct {

Filename string

Pos Pos

Text string

Incomplete bool

}

func (e ParseError) Error() string {

if e.Filename == "" {

return fmt.Sprintf("%s: %s", e.Pos.String(), e.Text)

}

return fmt.Sprintf("%s:%s: %s", e.Filename, e.Pos.String(), e.Text)

}

// LangError is returned when the parser encounters code that is only valid in

// other shell language variants. The error includes what feature is not present

// in the current language variant, and what languages support it.

type LangError struct {

Filename string

Pos Pos

Feature string

Langs []LangVariant

}

func (e LangError) Error() string {

var buf bytes.Buffer

if e.Filename != "" {

buf.WriteString(e.Filename + ":")

}

buf.WriteString(e.Pos.String() + ": ")

buf.WriteString(e.Feature)

if strings.HasSuffix(e.Feature, "s") {

buf.WriteString(" are a ")

} else {

buf.WriteString(" is a ")

}

for i, lang := range e.Langs {

if i > 0 {

buf.WriteString("/")

}

buf.WriteString(lang.String())

}

buf.WriteString(" feature")

return buf.String()

}

func (p *Parser) posErr(pos Pos, format string, a ...any) {

p.errPass(ParseError{

Filename: p.f.Name,

Pos: pos,

Text: fmt.Sprintf(format, a...),

Incomplete: p.tok == _EOF && p.Incomplete(),

})

}

func (p *Parser) curErr(format string, a ...any) {

p.posErr(p.pos, format, a...)

}

func (p *Parser) langErr(pos Pos, feature string, langs ...LangVariant) {

p.errPass(LangError{

Filename: p.f.Name,

Pos: pos,

Feature: feature,

Langs: langs,

})

}

func (p *Parser) stmts(fn func(*Stmt) bool, stops ...string) {

gotEnd := true

loop:

for p.tok != _EOF {

newLine := p.got(_Newl)

switch p.tok {

case _LitWord:

for _, stop := range stops {

if p.val == stop {

break loop

}

case rightParen:

if p.quote == subCmd {

break loop

}

case bckQuote:

if p.backquoteEnd() {

break loop

}

case dblSemicolon, semiAnd, dblSemiAnd, semiOr:

if p.quote == switchCase {

break loop

}

p.curErr("%s can only be used in a case clause", p.tok)

}

if !newLine && !gotEnd {

p.curErr("statements must be separated by &, ; or a newline")

}

if p.tok == _EOF {

break

}

p.openStmts++

s := p.getStmt(true, false, false)

p.openStmts--

if s == nil {

p.invalidStmtStart()

break

}

gotEnd = s.Semicolon.IsValid()

if !fn(s) {

break

}

func (p *Parser) stmtList(stops ...string) ([]*Stmt, []Comment) {

var stmts []*Stmt

var last []Comment

fn := func(s *Stmt) bool {

stmts = append(stmts, s)

return true

}

p.stmts(fn, stops...)

split := len(p.accComs)

if p.tok == _LitWord && (p.val == "elif" || p.val == "else" || p.val == "fi") {

// Split the comments, so that any aligned with an opening token

// get attached to it. For example:

// if foo; then

// # inside the body

// # document the else

// else

// fi

// TODO(mvdan): look into deduplicating this with similar logic

// in caseItems.

for i := len(p.accComs) - 1; i >= 0; i-- {

c := p.accComs[i]

if c.Pos().Col() != p.pos.Col() {

break

}

split = i

}

if split > 0 { // keep last nil if empty

last = p.accComs[:split]

}

p.accComs = p.accComs[split:]

return stmts, last

}

func (p *Parser) invalidStmtStart() {

switch p.tok {

case semicolon, and, or, andAnd, orOr:

p.curErr("%s can only immediately follow a statement", p.tok)

case rightParen:

p.curErr("%s can only be used to close a subshell", p.tok)

default:

p.curErr("%s is not a valid start for a statement", p.tok)

}

func (p *Parser) getWord() *Word {

if w := p.wordAnyNumber(); len(w.Parts) > 0 && p.err == nil {

return w

}

return nil

}

func (p *Parser) getLit() *Lit {

switch p.tok {

case _Lit, _LitWord, _LitRedir:

l := p.lit(p.pos, p.val)

p.next()

return l

}

return nil

}

func (p *Parser) wordParts(wps []WordPart) []WordPart {

for {

n := p.wordPart()

if n == nil {

if len(wps) == 0 {

return nil // normalize empty lists into nil

}

return wps

}

wps = append(wps, n)

if p.spaced {

return wps

}

func (p *Parser) ensureNoNested() {

if p.forbidNested {

p.curErr("expansions not allowed in heredoc words")

View remainder of file in raw view

sh/syntax/parser.go at master · thebeastunleashed/sh · GitHub

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