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goyacc: provide -p flag to set prefix for names.

Browse Source 
This should allow multiple goyacc grammars to be
compiled into the same binary. There's a chance it
Fixes #1562.

R=rsc, r2
CC=golang-dev
https://golang.org/cl/4256044
This commit is contained in:
Rob Pike 2011-02-28 17:43:16 -08:00
parent 432b4f309b
commit bb0e7bda35
4 changed files with 175 additions and 161 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
src/cmd/goyacc/Makefile
View File

@ -11,7 +11,7 @@ GOFILES=\
include ../../Make.cmd
units: goyacc units.y
./goyacc units.y
./goyacc -p units_ units.y
$(GC) y.go
$(LD) -o units y.$O

11
src/cmd/goyacc/doc.go
View File

@ -17,7 +17,8 @@ Yacc adepts will have no trouble adapting to this form of the tool.
The file units.y in this directory is a yacc grammar for a version of
the Unix tool units, also written in Go and largely transliterated
from the Plan 9 C version.
from the Plan 9 C version. It needs the flag "-p units_" (see
below).
The generated parser is reentrant. Parse expects to be given an
argument that conforms to the following interface:
@ -31,8 +32,14 @@ Lex should return the token identifier, and place other token
information in lval (which replaces the usual yylval).
Error is equivalent to yyerror in the original yacc.
Code inside the parser may refer to the variable yylex
Code inside the parser may refer to the variable yylex,
which holds the yyLexer passed to Parse.
The "-p prefix" flag to goyacc sets the prefix, by default yy, that
begins the names of symbols, including types, the parser, and the
lexer, generated and referenced by goyacc's generated code. Setting
it to distinct values allows multiple grammars to be used in a
single binary.
*/
package documentation

308
src/cmd/goyacc/goyacc.go
View File

@ -156,6 +156,14 @@ var foutput *bufio.Writer // y.output file
var oflag string // -o [y.go] - y.go file
var vflag string // -v [y.output] - y.output file
var lflag bool // -l - disable line directives
var prefix string // name prefix for identifiers, default yy
func init() {
flag.StringVar(&oflag, "o", "y.go", "parser output")
flag.StringVar(&prefix, "p", "yy", "name prefix to use in generated code")
flag.StringVar(&vflag, "v", "y.output", "create parsing tables")
flag.BoolVar(&lflag, "l", false, "disable line directives")
}
var stacksize = 200
@ -349,10 +357,6 @@ func setup() {
stderr = bufio.NewWriter(os.NewFile(2, "stderr"))
foutput = nil
flag.StringVar(&oflag, "o", "", "parser output")
flag.StringVar(&vflag, "v", "", "create parsing tables")
flag.BoolVar(&lflag, "l", false, "disable line directives")
flag.Parse()
if flag.NArg() != 1 {
usage()
@ -362,6 +366,7 @@ func setup() {
fmt.Fprintf(stderr, "yacc: stack size too small\n")
usage()
}
yaccpar = strings.Replace(yaccpartext, "$$", prefix, -1)
openup()
defin(0, "$end")
@ -506,20 +511,20 @@ outer:
}
// put out names of token names
fmt.Fprintf(ftable, "var\tyyToknames\t =[]string {\n")
fmt.Fprintf(ftable, "var\t%sToknames\t =[]string {\n", prefix)
for i := TOKSTART; i <= ntokens; i++ {
fmt.Fprintf(ftable, "\t\"%v\",\n", tokset[i].name)
}
fmt.Fprintf(ftable, "}\n")
// put out names of state names
fmt.Fprintf(ftable, "var\tyyStatenames\t =[]string {\n")
fmt.Fprintf(ftable, "var\t%sStatenames\t =[]string {\n", prefix)
// for i:=TOKSTART; i<=ntokens; i++ {
// fmt.Fprintf(ftable, "\t\"%v\",\n", tokset[i].name);
// }
fmt.Fprintf(ftable, "}\n")
fmt.Fprintf(fcode, "switch yynt {\n")
fmt.Fprintf(fcode, "switch %snt {\n", prefix)
moreprod()
prdptr[0] = []int{NTBASE, start, 1, 0}
@ -648,8 +653,8 @@ outer:
error("default action causes potential type clash")
}
fmt.Fprintf(fcode, "\ncase %v:", nprod)
fmt.Fprintf(fcode, "\n\tYYVAL.%v = YYS[yypt-0].%v;",
typeset[tempty], typeset[tempty])
fmt.Fprintf(fcode, "\n\t%sVAL.%v = %sS[%spt-0].%v;",
prefix, typeset[tempty], prefix, prefix, typeset[tempty])
}
moreprod()
prdptr[nprod] = make([]int, mem)
@ -666,9 +671,9 @@ outer:
fmt.Fprintf(fcode, "\n\t}")
fmt.Fprintf(ftable, "const yyEofCode = 1\n")
fmt.Fprintf(ftable, "const yyErrCode = 2\n")
fmt.Fprintf(ftable, "const yyMaxDepth = %v\n", stacksize)
fmt.Fprintf(ftable, "const %sEofCode = 1\n", prefix)
fmt.Fprintf(ftable, "const %sErrCode = 2\n", prefix)
fmt.Fprintf(ftable, "const %sMaxDepth = %v\n", prefix, stacksize)
//
// copy any postfix code
@ -1034,7 +1039,7 @@ func cpyunion() {
if !lflag {
fmt.Fprintf(ftable, "\n//line %v:%v\n", infile, lineno)
}
fmt.Fprintf(ftable, "type\tyySymType\tstruct")
fmt.Fprintf(ftable, "type\t%sSymType\tstruct", prefix)
level := 0
@ -1197,7 +1202,7 @@ loop:
c = getrune(finput)
}
if c == '$' {
fmt.Fprintf(fcode, "YYVAL")
fmt.Fprintf(fcode, "%sVAL", prefix)
// put out the proper tag...
if ntypes != 0 {
@ -1258,7 +1263,7 @@ loop:
ungetrune(finput, c)
continue loop
}
fmt.Fprintf(fcode, "YYS[yypt-%v]", max-j-1)
fmt.Fprintf(fcode, "%sS[%spt-%v]", prefix, prefix, max-j-1)
// put out the proper tag
if ntypes != 0 {
@ -2067,7 +2072,7 @@ func output() {
var c, u, v int
fmt.Fprintf(ftable, "\n//line yacctab:1\n")
fmt.Fprintf(ftable, "var\tyyExca = []int {\n")
fmt.Fprintf(ftable, "var\t%sExca = []int {\n", prefix)
noset := mkset()
@ -2140,10 +2145,10 @@ func output() {
}
fmt.Fprintf(ftable, "}\n")
fmt.Fprintf(ftable, "const\tyyNprod\t= %v\n", nprod)
fmt.Fprintf(ftable, "const\tyyPrivate\t= %v\n", PRIVATE)
fmt.Fprintf(ftable, "var\tyyTokenNames []string\n")
fmt.Fprintf(ftable, "var\tyyStates []string\n")
fmt.Fprintf(ftable, "const\t%sNprod\t= %v\n", prefix, nprod)
fmt.Fprintf(ftable, "const\t%sPrivate\t= %v\n", prefix, PRIVATE)
fmt.Fprintf(ftable, "var\t%sTokenNames []string\n", prefix)
fmt.Fprintf(ftable, "var\t%sStates []string\n", prefix)
}
//
@ -2718,10 +2723,10 @@ nextn:
// write out the optimized parser
//
func aoutput() {
fmt.Fprintf(ftable, "const\tyyLast\t= %v\n", maxa+1)
arout("yyAct", amem, maxa+1)
arout("yyPact", indgo, nstate)
arout("yyPgo", pgo, nnonter+1)
fmt.Fprintf(ftable, "const\t%sLast\t= %v\n", prefix, maxa+1)
arout("Act", amem, maxa+1)
arout("Pact", indgo, nstate)
arout("Pgo", pgo, nnonter+1)
}
//
@ -2730,7 +2735,7 @@ func aoutput() {
func others() {
var i, j int
arout("yyR1", levprd, nprod)
arout("R1", levprd, nprod)
aryfil(temp1, nprod, 0)
//
@ -2739,7 +2744,7 @@ func others() {
for i = 1; i < nprod; i++ {
temp1[i] = len(prdptr[i]) - 2
}
arout("yyR2", temp1, nprod)
arout("R2", temp1, nprod)
aryfil(temp1, nstate, -1000)
for i = 0; i <= ntokens; i++ {
@ -2752,8 +2757,8 @@ func others() {
temp1[j] = -i
}
}
arout("yyChk", temp1, nstate)
arout("yyDef", defact, nstate)
arout("Chk", temp1, nstate)
arout("Def", defact, nstate)
// put out token translation tables
// table 1 has 0-256
@ -2778,7 +2783,7 @@ func others() {
temp1[i] = YYLEXUNK
}
}
arout("yyTok1", temp1, c+1)
arout("Tok1", temp1, c+1)
// table 2 has PRIVATE-PRIVATE+256
aryfil(temp1, 256, 0)
@ -2797,10 +2802,10 @@ func others() {
}
}
}
arout("yyTok2", temp1, c+1)
arout("Tok2", temp1, c+1)
// table 3 has everything else
fmt.Fprintf(ftable, "var\tyyTok3\t= []int {\n")
fmt.Fprintf(ftable, "var\t%sTok3\t= []int {\n", prefix)
c = 0
for i = 1; i <= ntokens; i++ {
j = tokset[i].value
@ -2829,13 +2834,14 @@ func others() {
// copy yaccpar
fmt.Fprintf(ftable, "\n//line yaccpar:1\n")
parts := strings.Split(yaccpar, "yyrun()", 2)
parts := strings.Split(yaccpar, prefix+"run()", 2)
fmt.Fprintf(ftable, "%v", parts[0])
ftable.Write(fcode.Bytes())
fmt.Fprintf(ftable, "%v", parts[1])
}
func arout(s string, v []int, n int) {
s = prefix + s
fmt.Fprintf(ftable, "var\t%v\t= []int {\n", s)
for i := 0; i < n; i++ {
if i%10 == 0 {
@ -3076,86 +3082,84 @@ func exit(status int) {
os.Exit(status)
}
var yaccpar = `
var yaccpar string // will be processed version of yaccpartext: s/$$/prefix/g
var yaccpartext = `
/* parser for yacc output */
var yyDebug = 0
var $$Debug = 0
type yyLexer interface {
Lex(lval *yySymType) int
type $$Lexer interface {
Lex(lval *$$SymType) int
Error(s string)
}
const yyFlag = -1000
const $$Flag = -1000
func yyTokname(yyc int) string {
if yyc > 0 && yyc <= len(yyToknames) {
if yyToknames[yyc-1] != "" {
return yyToknames[yyc-1]
func $$Tokname(c int) string {
if c > 0 && c <= len($$Toknames) {
if $$Toknames[c-1] != "" {
return $$Toknames[c-1]
}
}
return fmt.Sprintf("tok-%v", yyc)
return fmt.Sprintf("tok-%v", c)
}
func yyStatname(yys int) string {
if yys >= 0 && yys < len(yyStatenames) {
if yyStatenames[yys] != "" {
return yyStatenames[yys]
func $$Statname(s int) string {
if s >= 0 && s < len($$Statenames) {
if $$Statenames[s] != "" {
return $$Statenames[s]
}
}
return fmt.Sprintf("state-%v", yys)
return fmt.Sprintf("state-%v", s)
}
func yylex1(yylex yyLexer, lval *yySymType) int {
var yychar int
var c int
yychar = yylex.Lex(lval)
if yychar <= 0 {
c = yyTok1[0]
func $$lex1(lex $$Lexer, lval *$$SymType) int {
c := 0
char := lex.Lex(lval)
if char <= 0 {
c = $$Tok1[0]
goto out
}
if yychar < len(yyTok1) {
c = yyTok1[yychar]
if char < len($$Tok1) {
c = $$Tok1[char]
goto out
}
if yychar >= yyPrivate {
if yychar < yyPrivate+len(yyTok2) {
c = yyTok2[yychar-yyPrivate]
if char >= $$Private {
if char < $$Private+len($$Tok2) {
c = $$Tok2[char-$$Private]
goto out
}
}
for i := 0; i < len(yyTok3); i += 2 {
c = yyTok3[i+0]
if c == yychar {
c = yyTok3[i+1]
for i := 0; i < len($$Tok3); i += 2 {
c = $$Tok3[i+0]
if c == char {
c = $$Tok3[i+1]
goto out
}
}
c = 0
out:
if c == 0 {
c = yyTok2[1] /* unknown char */
c = $$Tok2[1] /* unknown char */
}
if yyDebug >= 3 {
fmt.Printf("lex %U %s\n", uint(yychar), yyTokname(c))
if $$Debug >= 3 {
fmt.Printf("lex %U %s\n", uint(char), $$Tokname(c))
}
return c
}
func yyParse(yylex yyLexer) int {
var yyn int
var yylval yySymType
var YYVAL yySymType
YYS := make([]yySymType, yyMaxDepth)
func $$Parse($$lex $$Lexer) int {
var $$n int
var $$lval $$SymType
var $$VAL $$SymType
$$S := make([]$$SymType, $$MaxDepth)
Nerrs := 0 /* number of errors */
Errflag := 0 /* error recovery flag */
yystate := 0
yychar := -1
yyp := -1
goto yystack
$$state := 0
$$char := -1
$$p := -1
goto $$stack
ret0:
return 0
@ -3163,80 +3167,80 @@ ret0:
ret1:
return 1
yystack:
$$stack:
/* put a state and value onto the stack */
if yyDebug >= 4 {
fmt.Printf("char %v in %v\n", yyTokname(yychar), yyStatname(yystate))
if $$Debug >= 4 {
fmt.Printf("char %v in %v\n", $$Tokname($$char), $$Statname($$state))
}
yyp++
if yyp >= len(YYS) {
nyys := make([]yySymType, len(YYS)*2)
copy(nyys, YYS)
YYS = nyys
$$p++
if $$p >= len($$S) {
nyys := make([]$$SymType, len($$S)*2)
copy(nyys, $$S)
$$S = nyys
}
YYS[yyp] = YYVAL
YYS[yyp].yys = yystate
$$S[$$p] = $$VAL
$$S[$$p].yys = $$state
yynewstate:
yyn = yyPact[yystate]
if yyn <= yyFlag {
goto yydefault /* simple state */
$$newstate:
$$n = $$Pact[$$state]
if $$n <= $$Flag {
goto $$default /* simple state */
}
if yychar < 0 {
yychar = yylex1(yylex, &yylval)
if $$char < 0 {
$$char = $$lex1($$lex, &$$lval)
}
yyn += yychar
if yyn < 0 || yyn >= yyLast {
goto yydefault
$$n += $$char
if $$n < 0 || $$n >= $$Last {
goto $$default
}
yyn = yyAct[yyn]
if yyChk[yyn] == yychar { /* valid shift */
yychar = -1
YYVAL = yylval
yystate = yyn
$$n = $$Act[$$n]
if $$Chk[$$n] == $$char { /* valid shift */
$$char = -1
$$VAL = $$lval
$$state = $$n
if Errflag > 0 {
Errflag--
}
goto yystack
goto $$stack
}
yydefault:
$$default:
/* default state action */
yyn = yyDef[yystate]
if yyn == -2 {
if yychar < 0 {
yychar = yylex1(yylex, &yylval)
$$n = $$Def[$$state]
if $$n == -2 {
if $$char < 0 {
$$char = $$lex1($$lex, &$$lval)
}
/* look through exception table */
yyxi := 0
xi := 0
for {
if yyExca[yyxi+0] == -1 && yyExca[yyxi+1] == yystate {
if $$Exca[xi+0] == -1 && $$Exca[xi+1] == $$state {
break
}
yyxi += 2
xi += 2
}
for yyxi += 2; ; yyxi += 2 {
yyn = yyExca[yyxi+0]
if yyn < 0 || yyn == yychar {
for xi += 2; ; xi += 2 {
$$n = $$Exca[xi+0]
if $$n < 0 || $$n == $$char {
break
}
}
yyn = yyExca[yyxi+1]
if yyn < 0 {
$$n = $$Exca[xi+1]
if $$n < 0 {
goto ret0
}
}
if yyn == 0 {
if $$n == 0 {
/* error ... attempt to resume parsing */
switch Errflag {
case 0: /* brand new error */
yylex.Error("syntax error")
$$lex.Error("syntax error")
Nerrs++
if yyDebug >= 1 {
fmt.Printf("%s", yyStatname(yystate))
fmt.Printf("saw %s\n", yyTokname(yychar))
if $$Debug >= 1 {
fmt.Printf("%s", $$Statname($$state))
fmt.Printf("saw %s\n", $$Tokname($$char))
}
fallthrough
@ -3244,64 +3248,64 @@ yydefault:
Errflag = 3
/* find a state where "error" is a legal shift action */
for yyp >= 0 {
yyn = yyPact[YYS[yyp].yys] + yyErrCode
if yyn >= 0 && yyn < yyLast {
yystate = yyAct[yyn] /* simulate a shift of "error" */
if yyChk[yystate] == yyErrCode {
goto yystack
for $$p >= 0 {
$$n = $$Pact[$$S[$$p].yys] + $$ErrCode
if $$n >= 0 && $$n < $$Last {
$$state = $$Act[$$n] /* simulate a shift of "error" */
if $$Chk[$$state] == $$ErrCode {
goto $$stack
}
}
/* the current yyp has no shift onn "error", pop stack */
if yyDebug >= 2 {
/* the current p has no shift onn "error", pop stack */
if $$Debug >= 2 {
fmt.Printf("error recovery pops state %d, uncovers %d\n",
YYS[yyp].yys, YYS[yyp-1].yys)
$$S[$$p].yys, $$S[$$p-1].yys)
}
yyp--
$$p--
}
/* there is no state on the stack with an error shift ... abort */
goto ret1
case 3: /* no shift yet; clobber input char */
if yyDebug >= 2 {
fmt.Printf("error recovery discards %s\n", yyTokname(yychar))
if $$Debug >= 2 {
fmt.Printf("error recovery discards %s\n", $$Tokname($$char))
}
if yychar == yyEofCode {
if $$char == $$EofCode {
goto ret1
}
yychar = -1
goto yynewstate /* try again in the same state */
$$char = -1
goto $$newstate /* try again in the same state */
}
}
/* reduction by production yyn */
if yyDebug >= 2 {
fmt.Printf("reduce %v in:\n\t%v\n", yyn, yyStatname(yystate))
/* reduction by production $$n */
if $$Debug >= 2 {
fmt.Printf("reduce %v in:\n\t%v\n", $$n, $$Statname($$state))
}
yynt := yyn
yypt := yyp
_ = yypt // guard against "declared and not used"
$$nt := $$n
$$pt := $$p
_ = $$pt // guard against "declared and not used"
yyp -= yyR2[yyn]
YYVAL = YYS[yyp+1]
$$p -= $$R2[$$n]
$$VAL = $$S[$$p+1]
/* consult goto table to find next state */
yyn = yyR1[yyn]
yyg := yyPgo[yyn]
yyj := yyg + YYS[yyp].yys + 1
$$n = $$R1[$$n]
$$g := $$Pgo[$$n]
$$j := $$g + $$S[$$p].yys + 1
if yyj >= yyLast {
yystate = yyAct[yyg]
if $$j >= $$Last {
$$state = $$Act[$$g]
} else {
yystate = yyAct[yyj]
if yyChk[yystate] != -yyn {
yystate = yyAct[yyg]
$$state = $$Act[$$j]
if $$Chk[$$state] != -$$n {
$$state = $$Act[$$g]
}
}
// dummy call; replaced with literal code
yyrun()
goto yystack /* stack new state and value */
$$run()
goto $$stack /* stack new state and value */
}
`

9
src/cmd/goyacc/units.y
View File

@ -6,6 +6,9 @@
// Distributed under the terms of the Lucent Public License Version 1.02
// See http://plan9.bell-labs.com/plan9/license.html
// Generate parser with prefix "units_":
// goyacc -p "units_"
%{
// units.y
@ -215,7 +218,7 @@ expr0:
type UnitsLex int
func (UnitsLex) Lex(yylval *yySymType) int {
func (UnitsLex) Lex(yylval *units_SymType) int {
var c, i int
c = peekrune
@ -319,7 +322,7 @@ func main() {
continue
}
peekrune = ':'
yyParse(UnitsLex(0))
units_Parse(UnitsLex(0))
}
/*
@ -340,7 +343,7 @@ func main() {
}
peekrune = '?'
nerrors = 0
yyParse(UnitsLex(0))
units_Parse(UnitsLex(0))
if nerrors != 0 {
continue
}