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|
package main
import (
"fmt"
"strconv"
)
func parseShellProgram(line *Line, program string) (list *MkShList, err error) {
if G.opts.Debug {
defer tracecall(program)()
}
tokens, rest := splitIntoShellTokens(line, program)
lexer := NewShellLexer(tokens, rest)
parser := ­yParserImpl{}
succeeded := parser.Parse(lexer)
if succeeded == 0 && lexer.error == "" {
return lexer.result, nil
}
return nil, &ParseError{append([]string{lexer.current}, lexer.remaining...)}
}
type ParseError struct {
RemainingTokens []string
}
func (e *ParseError) Error() string {
return fmt.Sprintf("parse error at %v", e.RemainingTokens)
}
type ShellLexer struct {
current string
ioredirect string
remaining []string
atCommandStart bool
sinceFor int
sinceCase int
error string
result *MkShList
}
func NewShellLexer(tokens []string, rest string) *ShellLexer {
return &ShellLexer{
current: "",
ioredirect: "",
remaining: tokens,
atCommandStart: true,
error: rest}
}
func (lex *ShellLexer) Lex(lval *shyySymType) (ttype int) {
if len(lex.remaining) == 0 {
return 0
}
if G.opts.Debug {
defer func() {
tname := shyyTokname(shyyTok2[ttype-shyyPrivate])
switch ttype {
case tkWORD, tkASSIGNMENT_WORD:
traceStep("lex %v %q", tname, lval.Word.MkText)
case tkIO_NUMBER:
traceStep("lex %v %v", tname, lval.IONum)
default:
traceStep("lex %v", tname)
}
}()
}
token := lex.ioredirect
lex.ioredirect = ""
if token == "" {
token = lex.remaining[0]
lex.current = token
lex.remaining = lex.remaining[1:]
}
switch token {
case ";":
lex.atCommandStart = true
return tkSEMI
case ";;":
lex.atCommandStart = true
return tkSEMISEMI
case "\n":
lex.atCommandStart = true
return tkNEWLINE
case "&":
lex.atCommandStart = true
return tkBACKGROUND
case "|":
lex.atCommandStart = true
return tkPIPE
case "(":
lex.atCommandStart = true
return tkLPAREN
case ")":
lex.atCommandStart = true
return tkRPAREN
case "&&":
lex.atCommandStart = true
return tkAND
case "||":
lex.atCommandStart = true
return tkOR
case ">":
lex.atCommandStart = false
return tkGT
case ">&":
lex.atCommandStart = false
return tkGTAND
case "<":
lex.atCommandStart = false
return tkLT
case "<&":
lex.atCommandStart = false
return tkLTAND
case "<>":
lex.atCommandStart = false
return tkLTGT
case ">>":
lex.atCommandStart = false
return tkGTGT
case "<<":
lex.atCommandStart = false
return tkLTLT
case "<<-":
lex.atCommandStart = false
return tkLTLTDASH
case ">|":
lex.atCommandStart = false
return tkGTPIPE
}
if m, fdstr, op := match2(token, `^(\d+)(<<-|<<|<>|<&|>>|>&|>\||<|>)$`); m {
fd, _ := strconv.Atoi(fdstr)
lval.IONum = fd
lex.ioredirect = op
return tkIO_NUMBER
}
if lex.atCommandStart {
lex.sinceCase = -1
lex.sinceFor = -1
switch token {
case "if":
return tkIF
case "then":
return tkTHEN
case "elif":
return tkELIF
case "else":
return tkELSE
case "fi":
return tkFI
case "for":
lex.atCommandStart = false
lex.sinceFor = 0
return tkFOR
case "while":
return tkWHILE
case "until":
return tkUNTIL
case "do":
return tkDO
case "done":
return tkDONE
case "in":
lex.atCommandStart = false
return tkIN
case "case":
lex.atCommandStart = false
lex.sinceCase = 0
return tkCASE
case "{":
return tkLBRACE
case "}":
return tkRBRACE
case "!":
return tkEXCLAM
}
}
if lex.sinceFor >= 0 {
lex.sinceFor++
}
if lex.sinceCase >= 0 {
lex.sinceCase++
}
switch {
case lex.sinceFor == 2 && token == "in":
ttype = tkIN
lex.atCommandStart = false
case lex.sinceFor == 2 && token == "do":
ttype = tkDO
lex.atCommandStart = true
case lex.sinceCase == 2 && token == "in":
ttype = tkIN
lex.atCommandStart = false
case (lex.atCommandStart || lex.sinceCase == 3) && token == "esac":
ttype = tkESAC
lex.atCommandStart = false
case lex.atCommandStart && matches(token, `^[A-Za-z_]\w*=`):
ttype = tkASSIGNMENT_WORD
p := NewShTokenizer(dummyLine, token, false)
lval.Word = p.ShToken()
default:
ttype = tkWORD
p := NewShTokenizer(dummyLine, token, false)
lval.Word = p.ShToken()
lex.atCommandStart = false
}
return ttype
}
func (lex *ShellLexer) Error(s string) {
lex.error = s
}
|
