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gc: semicolons

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Fixes #89.
Fixes #92.
Fixes #118.
Fixes #182.
Fixes #328.
Fixes #340.

R=ken2, ken3
CC=golang-dev
https://golang.org/cl/172049
This commit is contained in:
Russ Cox 2009-12-11 15:59:41 -08:00
parent cd00bc78da
commit 3997495dc3
3 changed files with 102 additions and 164 deletions
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6
src/cmd/gc/go.h
View File

@ -548,6 +548,7 @@ struct Io
char* infile;
Biobuf* bin;
int32 ilineno;
int nlsemi;
int peekc;
int peekc1; // second peekc for ...
char* cp; // used for content when bin==nil
@ -725,7 +726,6 @@ void importfile(Val*, int line);
void cannedimports(char*, char*);
void unimportfile();
int32 yylex(void);
void yyoptsemi(int);
void typeinit(void);
void lexinit(void);
char* lexname(int);
@ -1128,10 +1128,6 @@ EXTERN Prog* breakpc;
EXTERN Prog* pc;
EXTERN Prog* firstpc;
EXTERN int yylast;
EXTERN int yynext;
EXTERN int yysemi;
void allocparams(void);
void cgen_as(Node *nl, Node *nr);
void cgen_callmeth(Node *n, int proc);

121
src/cmd/gc/go.y
View File

@ -8,13 +8,14 @@
* The Go semicolon rules are:
*
* 1. all statements and declarations are terminated by semicolons
* 2. semicolons can be omitted at top level.
* 3. semicolons can be omitted before and after the closing ) or }
* 2. semicolons can be omitted before and after the closing ) or }
* on a list of statements or declarations.
* 3. semicolons are inserted by the lexer before a newline
* following a specific list of tokens.
*
* This is accomplished by calling yyoptsemi() to mark the places
* where semicolons are optional. That tells the lexer that if a
* semicolon isn't the next token, it should insert one for us.
* Rules #1 and #2 are accomplished by writing the lists as
* semicolon-separated lists with an optional trailing semicolon.
* Rule #3 is implemented in yylex.
*/
%{
@ -67,7 +68,7 @@
%type <list> xdcl fnbody fnres switch_body loop_body dcl_name_list
%type <list> new_name_list expr_list keyval_list braced_keyval_list expr_or_type_list xdcl_list
%type <list> oexpr_list oexpr_or_type_list caseblock_list stmt_list oarg_type_list arg_type_list
%type <list> oexpr_list oexpr_or_type_list_ocomma caseblock_list stmt_list oarg_type_list_ocomma arg_type_list
%type <list> interfacedcl_list vardcl vardcl_list structdcl structdcl_list
%type <list> common_dcl constdcl constdcl1 constdcl_list typedcl_list
@ -112,13 +113,6 @@
%left ')'
%left PreferToRightParen
%left '.'
%left '{'
%left NotSemi
%left ';'
%%
file:
loadsys
@ -134,9 +128,10 @@ package:
{
prevlineno = lineno;
yyerror("package statement must be first");
flusherrors();
mkpackage("main");
}
| LPACKAGE sym
| LPACKAGE sym ';'
{
mkpackage($2->name);
}
@ -157,12 +152,12 @@ loadsys:
}
imports:
| imports import
| imports import ';'
import:
LIMPORT import_stmt osemi
| LIMPORT '(' import_stmt_list osemi ')' osemi
| LIMPORT '(' ')' osemi
LIMPORT import_stmt
| LIMPORT '(' import_stmt_list osemi ')'
| LIMPORT '(' ')'
import_stmt:
import_here import_package import_there
@ -235,7 +230,7 @@ import_here:
}
import_package:
LPACKAGE sym
LPACKAGE sym ';'
{
pkgimportname = $2;
if(strcmp($2->name, "main") == 0)
@ -265,43 +260,39 @@ import_there:
{
resumecheckwidth();
checkimports();
unimportfile();
}
/*
* declarations
*/
xdcl:
common_dcl osemi
| xfndcl osemi
{
yyerror("empty top-level declaration");
$$ = nil;
}
| common_dcl
| xfndcl
{
$$ = list1($1);
}
| error osemi
| error
{
$$ = nil;
}
| ';'
{
yyerror("empty top-level declaration");
$$ = nil;
}
common_dcl:
LVAR vardcl
{
$$ = $2;
if(yylast == LSEMIBRACE)
yyoptsemi(0);
}
| LVAR '(' vardcl_list osemi ')'
{
$$ = $3;
yyoptsemi(0);
}
| LVAR '(' ')'
{
$$ = nil;
yyoptsemi(0);
}
| LCONST constdcl
{
@ -314,51 +305,38 @@ common_dcl:
$$ = $3;
iota = 0;
lastconst = nil;
yyoptsemi(0);
}
| LCONST '(' constdcl ';' constdcl_list osemi ')'
{
$$ = concat($3, $5);
iota = 0;
lastconst = nil;
yyoptsemi(0);
}
| LCONST '(' ')'
{
$$ = nil;
yyoptsemi(0);
}
| LTYPE typedcl
{
$$ = list1($2);
if(yylast == LSEMIBRACE)
yyoptsemi(0);
}
| LTYPE '(' typedcl_list osemi ')'
{
$$ = $3;
yyoptsemi(0);
}
| LTYPE '(' ')'
{
$$ = nil;
yyoptsemi(0);
}
varoptsemi:
{
if(yylast == LSEMIBRACE)
yyoptsemi('=');
}
vardcl:
dcl_name_list ntype varoptsemi
dcl_name_list ntype
{
$$ = variter($1, $2, nil);
}
| dcl_name_list ntype varoptsemi '=' expr_list
| dcl_name_list ntype '=' expr_list
{
$$ = variter($1, $2, $5);
$$ = variter($1, $2, $4);
}
| dcl_name_list '=' expr_list
{
@ -508,7 +486,6 @@ compound_stmt:
{
$$ = liststmt($3);
popdcl();
yyoptsemi(0);
}
switch_body:
@ -520,7 +497,6 @@ switch_body:
{
$$ = $3;
popdcl();
yyoptsemi(0);
}
caseblock:
@ -590,7 +566,6 @@ for_body:
{
$$ = $1;
$$->nbody = concat($$->nbody, $2);
yyoptsemi(0);
}
for_stmt:
@ -630,7 +605,6 @@ if_stmt:
$$ = $3;
$$->nbody = $4;
// no popdcl; maybe there's an LELSE
yyoptsemi(LELSE);
}
switch_stmt:
@ -794,7 +768,7 @@ uexpr:
* can be preceded by 'defer' and 'go'
*/
pseudocall:
pexpr '(' oexpr_or_type_list ')'
pexpr '(' oexpr_or_type_list_ocomma ')'
{
$$ = nod(OCALL, $1, N);
$$->list = $3;
@ -1054,15 +1028,10 @@ structtype:
{
$$ = nod(OTSTRUCT, N, N);
$$->list = $3;
// Distinguish closing brace in struct from
// other closing braces by explicitly marking it.
// Used above (yylast == LSEMIBRACE).
yylast = LSEMIBRACE;
}
| LSTRUCT '{' '}'
{
$$ = nod(OTSTRUCT, N, N);
yylast = LSEMIBRACE;
}
interfacetype:
@ -1070,12 +1039,10 @@ interfacetype:
{
$$ = nod(OTINTER, N, N);
$$->list = $3;
yylast = LSEMIBRACE;
}
| LINTERFACE '{' '}'
{
$$ = nod(OTINTER, N, N);
yylast = LSEMIBRACE;
}
keyval:
@ -1100,7 +1067,7 @@ xfndcl:
}
fndcl:
dcl_name '(' oarg_type_list ')' fnres
dcl_name '(' oarg_type_list_ocomma ')' fnres
{
Node *n;
@ -1115,7 +1082,7 @@ fndcl:
$$->nname->ntype = n;
funchdr($$);
}
| '(' oarg_type_list ')' new_name '(' oarg_type_list ')' fnres
| '(' oarg_type_list_ocomma ')' new_name '(' oarg_type_list_ocomma ')' fnres
{
Node *rcvr, *t;
@ -1145,7 +1112,7 @@ fndcl:
}
fntype:
LFUNC '(' oarg_type_list ')' fnres
LFUNC '(' oarg_type_list_ocomma ')' fnres
{
$$ = nod(OTFUNC, N, N);
$$->list = $3;
@ -1161,7 +1128,6 @@ fnbody:
$$ = $2;
if($$ == nil)
$$ = list1(nod(OEMPTY, N, N));
yyoptsemi(0);
}
fnres:
@ -1173,7 +1139,7 @@ fnres:
{
$$ = list1(nod(ODCLFIELD, N, $1));
}
| '(' oarg_type_list ')'
| '(' oarg_type_list_ocomma ')'
{
$$ = $2;
}
@ -1201,7 +1167,7 @@ xdcl_list:
{
$$ = nil;
}
| xdcl_list xdcl
| xdcl_list xdcl ';'
{
$$ = concat($1, $2);
if(nsyntaxerrors == 0)
@ -1312,7 +1278,7 @@ interfacedcl:
}
indcl:
'(' oarg_type_list ')' fnres
'(' oarg_type_list_ocomma ')' fnres
{
// without func keyword
$$ = nod(OTFUNC, fakethis(), N);
@ -1349,11 +1315,11 @@ arg_type_list:
$$ = list($1, $3);
}
oarg_type_list:
oarg_type_list_ocomma:
{
$$ = nil;
}
| arg_type_list
| arg_type_list ocomma
{
$$ = checkarglist($1);
}
@ -1517,7 +1483,6 @@ braced_keyval_list:
* optional things
*/
osemi:
%prec NotSemi
| ';'
ocomma:
@ -1535,11 +1500,11 @@ oexpr_list:
}
| expr_list
oexpr_or_type_list:
oexpr_or_type_list_ocomma:
{
$$ = nil;
}
| expr_or_type_list
| expr_or_type_list ocomma
osimple_stmt:
{
@ -1576,29 +1541,29 @@ oliteral:
* an output package
*/
hidden_import:
LPACKAGE sym
LPACKAGE sym ';'
/* variables */
| LVAR hidden_pkg_importsym hidden_type
| LVAR hidden_pkg_importsym hidden_type ';'
{
importvar($2, $3, PEXTERN);
}
| LCONST hidden_pkg_importsym '=' hidden_constant
| LCONST hidden_pkg_importsym '=' hidden_constant ';'
{
importconst($2, types[TIDEAL], $4);
}
| LCONST hidden_pkg_importsym hidden_type '=' hidden_constant
| LCONST hidden_pkg_importsym hidden_type '=' hidden_constant ';'
{
importconst($2, $3, $5);
}
| LTYPE hidden_pkgtype hidden_type
| LTYPE hidden_pkgtype hidden_type ';'
{
importtype($2, $3);
}
| LFUNC hidden_pkg_importsym '(' ohidden_funarg_list ')' ohidden_funres
| LFUNC hidden_pkg_importsym '(' ohidden_funarg_list ')' ohidden_funres ';'
{
importvar($2, functype(N, $4, $6), PFUNC);
}
| LFUNC '(' hidden_funarg_list ')' sym '(' ohidden_funarg_list ')' ohidden_funres
| LFUNC '(' hidden_funarg_list ')' sym '(' ohidden_funarg_list ')' ohidden_funres ';'
{
if($3->next != nil || $3->n->op != ODCLFIELD) {
yyerror("bad receiver in method");

137
src/cmd/gc/lex.c
View File

@ -85,6 +85,7 @@ main(int argc, char *argv[])
fatal("open %s: %r", infile);
curio.peekc = 0;
curio.peekc1 = 0;
curio.nlsemi = 0;
block = 1;
@ -310,6 +311,7 @@ importfile(Val *f, int line)
curio.peekc = 0;
curio.peekc1 = 0;
curio.infile = file;
curio.nlsemi = 0;
typecheckok = 1;
for(;;) {
c = getc();
@ -354,6 +356,7 @@ cannedimports(char *file, char *cp)
curio.peekc1 = 0;
curio.infile = file;
curio.cp = cp;
curio.nlsemi = 0;
pkgmyname = S;
typecheckok = 1;
@ -389,8 +392,14 @@ _yylex(void)
l0:
c = getc();
if(isspace(c))
if(isspace(c)) {
if(c == '\n' && curio.nlsemi) {
ungetc(c);
DBG("lex: implicit semi\n");
return ';';
}
goto l0;
}
lineno = lexlineno; /* start of token */
@ -444,7 +453,6 @@ l0:
cp = mal(sizeof(int32));
clen = sizeof(int32);
caseq:
for(;;) {
if(escchar('"', &escflag, &v))
break;
@ -460,7 +468,7 @@ l0:
clen += c;
}
}
goto catem;
goto strlit;
case '`':
/* `...` */
@ -468,7 +476,6 @@ l0:
cp = mal(sizeof(int32));
clen = sizeof(int32);
casebq:
for(;;) {
c = getc();
if(c == EOF) {
@ -480,51 +487,8 @@ l0:
cp = remal(cp, clen, 1);
cp[clen++] = c;
}
goto catem;
catem:
c = getc();
if(isspace(c))
goto catem;
// skip comments
if(c == '/') {
c1 = getc();
if(c1 == '*') {
for(;;) {
c = getr();
while(c == '*') {
c = getr();
if(c == '/')
goto catem;
}
if(c == EOF) {
yyerror("eof in comment");
errorexit();
}
}
}
if(c1 == '/') {
for(;;) {
c = getr();
if(c == '\n')
goto catem;
if(c == EOF) {
yyerror("eof in comment");
errorexit();
}
}
}
ungetc(c1);
}
// cat adjacent strings
if(c == '"')
goto caseq;
if(c == '`')
goto casebq;
ungetc(c);
strlit:
*(int32*)cp = clen-sizeof(int32); // length
do {
cp = remal(cp, clen, 1);
@ -554,13 +518,23 @@ l0:
case '/':
c1 = getc();
if(c1 == '*') {
int nl;
nl = 0;
for(;;) {
c = getr();
if(c == '\n')
nl = 1;
while(c == '*') {
c = getr();
if(c == '/')
if(c == '/') {
if(nl)
ungetc('\n');
goto l0;
}
if(c == '\n')
nl = 1;
}
if(c == EOF) {
yyerror("eof in comment");
errorexit();
@ -570,8 +544,10 @@ l0:
if(c1 == '/') {
for(;;) {
c = getr();
if(c == '\n')
if(c == '\n') {
ungetc(c);
goto l0;
}
if(c == EOF) {
yyerror("eof in comment");
errorexit();
@ -962,42 +938,43 @@ caseout:
return LLITERAL;
}
/*
* help the parser. if the next token is not c and not ';',
* insert a ';' before it.
*/
void
yyoptsemi(int c)
{
if(c == 0)
c = -1;
if(yychar <= 0)
yysemi = c;
}
int32
yylex(void)
{
// if we delayed a token, return that one.
if(yynext) {
yylast = yynext;
yynext = 0;
return yylast;
int lx;
lx = _yylex();
if(curio.nlsemi && lx == EOF) {
// if the nlsemi bit is set, we'd be willing to
// insert a ; if we saw a \n, but we didn't.
// that means the final \n is missing.
// complain here, because we can give a
// good message. the syntax error we'd get
// otherwise is inscrutable.
yyerror("missing newline at end of file");
lx = ';';
}
yylast = _yylex();
// if there's an optional semicolon needed,
// delay the token we just read.
if(yysemi) {
if(yylast != ';' && yylast != yysemi) {
yynext = yylast;
yylast = ';';
switch(lx) {
case LNAME:
case LLITERAL:
case LBREAK:
case LCONTINUE:
case LFALL:
case LRETURN:
case LINC:
case LDEC:
case ')':
case '}':
case ']':
curio.nlsemi = 1;
break;
default:
curio.nlsemi = 0;
break;
}
yysemi = 0;
}
return yylast;
return lx;
}
int