V6/usr/source/s1/bc.y
%right '='
%left '+' '-'
%left '*' '/' '%'
%right '^'
%left UMINUS
%term LETTER DIGIT SQRT _IF FFF EQ
%term _WHILE _FOR NE LE GE INCR DECR
%term _RETURN _BREAK _DEFINE BASE OBASE SCALE
%term EQPL EQMI EQMUL EQDIV EQREM EQEXP
%term _AUTO DOT
%term QSTR
%{
char cary[1000], *cp { cary };
char string[1000], *str {string};
int crs '0';
int rcrs '0'; /* reset crs */
int bindx 0;
int lev 0;
int bstack[10] { 0 };
char *numb[15] {
" 0", " 1", " 2", " 3", " 4", " 5",
" 6", " 7", " 8", " 9", " 10", " 11",
" 12", " 13", " 14" };
int *pre, *post;
%}
%%
start :
| start stat tail
= output( $2 );
| start def dargs ')' '{' dlist slist '}'
={ bundle( pre, $7, post );
conout( $$, $2 );
rcrs = crs;
output( "" );
lev = bindx = 0;
}
;
dlist : tail
| dlist _AUTO dlets tail
;
stat : e
={ bundle( $1, "ps." ); }
|
={ bundle( "" ); }
| QSTR
={ bundle("[",$1,"]P");}
| LETTER '=' e
={ bundle( $3, "s", $1 ); }
| LETTER '[' e ']' '=' e
={ bundle( $6, $3, ":", geta($1)); }
| LETTER EQOP e
={ bundle( "l", $1, $3, $2, "s", $1 ); }
| LETTER '[' e ']' EQOP e
={ bundle($3, ";", geta($1), $6, $5, $3, ":", geta($1));}
| _BREAK
={ bundle( numb[lev-bstack[bindx-1]], "Q" ); }
| _RETURN '(' e ')'
= bundle( $3, post, numb[lev], "Q" );
| _RETURN '(' ')'
= bundle( "0", post, numb[lev], "Q" );
| SCALE e
= bundle( $2, "k" );
| SCALE '=' e
= bundle( $3, "k");
| SCALE EQOP e
= bundle("K",$3,$2,"k");
| BASE e
= bundle( $2, "i" );
| BASE '=' e
= bundle($3, "i");
| BASE EQOP e
= bundle("I",$3,$2,"i");
| OBASE e
= bundle( $2, "o" );
| OBASE '=' e
= bundle($3,"o");
| OBASE EQOP e
= bundle("O",$3,$2,"o");
| '{' slist '}'
={ $$ = $2; }
| FFF
={ bundle("f"); }
| error
={ bundle("c"); }
| _IF CRS BLEV '(' re ')' stat
={ conout( $7, $2 );
bundle( $5, $2, " " );
}
| _WHILE CRS '(' re ')' stat BLEV
={ bundle( $6, $4, $2 );
conout( $$, $2 );
bundle( $4, $2, " " );
}
| fprefix CRS re ';' e ')' stat BLEV
={ bundle( $7, $5, "s.", $3, $2 );
conout( $$, $2 );
bundle( $1, "s.", $3, $2, " " );
}
| '~' LETTER '=' e
={ bundle($4,"S",$2); }
;
EQOP : EQPL
={ $$ = "+"; }
| EQMI
={ $$ = "-"; }
| EQMUL
={ $$ = "*"; }
| EQDIV
={ $$ = "/"; }
| EQREM
={ $$ = "%%"; }
| EQEXP
={ $$ = "^"; }
;
fprefix : _FOR '(' e ';'
={ $$ = $3; }
;
BLEV :
={ --bindx; }
;
slist : stat
| slist tail stat
={ bundle( $1, $3 ); }
;
tail : '\n'
| ';'
;
re : e EQ e
= bundle( $1, $3, "=" );
| e '<' e
= bundle( $1, $3, ">" );
| e '>' e
= bundle( $1, $3, "<" );
| e NE e
= bundle( $1, $3, "!=" );
| e GE e
= bundle( $1, $3, "!>" );
| e LE e
= bundle( $1, $3, "!<" );
| e
= bundle( $1, " 0!=" );
;
e : e '+' e
= bundle( $1, $3, "+" );
| e '-' e
= bundle( $1, $3, "-" );
| '-' e %prec UMINUS
= bundle( " 0", $2, "-" );
| e '*' e
= bundle( $1, $3, "*" );
| e '/' e
= bundle( $1, $3, "/" );
| e '%' e
= bundle( $1, $3, "%%" );
| e '^' e
= bundle( $1, $3, "^" );
| LETTER '[' e ']'
={ bundle($3, ";", geta($1)); }
| LETTER INCR
= bundle( "l", $1, "d1+s", $1 );
| INCR LETTER
= bundle( "l", $2, "1+ds", $2 );
| DECR LETTER
= bundle( "l", $2, "1-ds", $2 );
| LETTER DECR
= bundle( "l", $1, "d1-s", $1 );
| LETTER '[' e ']' INCR
= bundle($3,";",geta($1),"d1+",$3,":",geta($1));
| INCR LETTER '[' e ']'
= bundle($4,";",geta($2),"1+d",$4,":",geta($2));
| LETTER '[' e ']' DECR
= bundle($3,";",geta($1),"d1-",$3,":",geta($1));
| DECR LETTER '[' e ']'
= bundle($4,";",geta($2),"1-d",$4,":",geta($2));
| SCALE INCR
= bundle("Kd1+k");
| INCR SCALE
= bundle("K1+dk");
| SCALE DECR
= bundle("Kd1-k");
| DECR SCALE
= bundle("K1-dk");
| BASE INCR
= bundle("Id1+i");
| INCR BASE
= bundle("I1+di");
| BASE DECR
= bundle("Id1-i");
| DECR BASE
= bundle("I1-di");
| OBASE INCR
= bundle("Od1+o");
| INCR OBASE
= bundle("O1+do");
| OBASE DECR
= bundle("Od1-o");
| DECR OBASE
= bundle("O1-do");
| LETTER '(' cargs ')'
= bundle( $3, "l", getf($1), "x" );
| LETTER '(' ')'
= bundle( "l", getf($1), "x" );
| cons
={ bundle( " ", $1 ); }
| DOT cons
={ bundle( " .", $2 ); }
| cons DOT cons
={ bundle( " ", $1, ".", $3 ); }
| cons DOT
={ bundle( " ", $1, "." ); }
| DOT
={ $$ = "l."; }
| LETTER
= { bundle( "l", $1 ); }
| LETTER '=' e
={ bundle( $3, "ds", $1 ); }
| LETTER EQOP e %prec '='
={ bundle( "l", $1, $3, $2, "ds", $1 ); }
| '(' e ')'
= { $$ = $2; }
| '?'
={ bundle( "?" ); }
| SQRT '(' e ')'
={ bundle( $3, "v" ); }
| '~' LETTER
={ bundle("L",$2); }
| SCALE e
= bundle($2,"dk");
| SCALE '=' e
= bundle($3,"dk");
| SCALE EQOP e %prec '='
= bundle("K",$3,$2,"dk");
| BASE e
= bundle($2,"di");
| BASE '=' e
= bundle($3,"di");
| BASE EQOP e %prec '='
= bundle("I",$3,$2,"di");
| OBASE e
= bundle($2,"do");
| OBASE '=' e
= bundle($3,"do");
| OBASE EQOP e %prec '='
= bundle("O",$3,$2,"do");
| SCALE
= bundle("K");
| BASE
= bundle("I");
| OBASE
= bundle("O");
;
cargs : eora
| cargs ',' eora
= bundle( $1, $3 );
;
eora: e
| LETTER '[' ']'
=bundle("l",geta($1));
;
cons : constant
={ *cp++ = '\0'; }
constant:
'_'
={ $$ = cp; *cp++ = '_'; }
| DIGIT
={ $$ = cp; *cp++ = $1; }
| constant DIGIT
={ *cp++ = $2; }
;
CRS :
={ $$ = cp; *cp++ = crs++; *cp++ = '\0'; bstack[bindx++] = lev++; }
;
def : _DEFINE LETTER '('
={ $$ = getf($2);
pre = "";
post = "";
lev = 1;
bstack[bindx=0] = 0;
}
;
dargs :
| lora
={ pp( $1 ); }
| dargs ',' lora
={ pp( $3 ); }
;
dlets : lora
={ tp($1); }
| dlets ',' lora
={ tp($3); }
;
lora : LETTER
| LETTER '[' ']'
={ $$ = geta($1); }
;
%%
# define error 256
int peekc -1;
int sargc;
int ifile;
char **sargv;
extern int fin;
char *funtab[26]{
01,02,03,04,05,06,07,010,011,012,013,014,015,016,017,
020,021,022,023,024,025,026,027,030,031,032 };
char *atab[26]{
0241,0242,0243,0244,0245,0246,0247,0250,0251,0252,0253,
0254,0255,0256,0257,0260,0261,0262,0263,0264,0265,0266,
0267,0270,0271,0272};
char *letr[26] {
"a","b","c","d","e","f","g","h","i","j",
"k","l","m","n","o","p","q","r","s","t",
"u","v","w","x","y","z" } ;
char *dot { "." };
yylex(){
int c,ch;
restart:
c = getc();
peekc = -1;
while( c == ' ' || c == '\t' ) c = getc();
if( c<= 'z' && c >= 'a' ) {
/* look ahead to look for reserved words */
peekc = getc();
if( peekc >= 'a' && peekc <= 'z' ){ /* must be reserved word */
if( c=='i' && peekc=='f' ){ c=_IF; goto skip; }
if( c=='w' && peekc=='h' ){ c=_WHILE; goto skip; }
if( c=='f' && peekc=='o' ){ c=_FOR; goto skip; }
if( c=='s' && peekc=='q' ){ c=SQRT; goto skip; }
if( c=='r' && peekc=='e' ){ c=_RETURN; goto skip; }
if( c=='b' && peekc=='r' ){ c=_BREAK; goto skip; }
if( c=='d' && peekc=='e' ){ c=_DEFINE; goto skip; }
if( c=='s' && peekc=='c' ){ c= SCALE; goto skip; }
if( c=='b' && peekc=='a' ){ c=BASE; goto skip; }
if( c=='o' && peekc=='b' ){ c=OBASE; goto skip; }
if( c=='d' && peekc=='i' ){ c=FFF; goto skip; }
if( c=='a' && peekc=='u' ){ c=_AUTO; goto skip; }
if( c == 'q' && peekc == 'u')getout();
/* could not be found */
return( error );
skip: /* skip over rest of word */
peekc = -1;
while( (ch = getc()) >= 'a' && ch <= 'z' );
peekc = ch;
return( c );
}
/* usual case; just one single letter */
yylval = letr[c-'a'];
return( LETTER );
}
if( c>= '0' && c <= '9' || c>= 'A' && c<= 'F' ){
yylval = c;
return( DIGIT );
}
switch( c ){
case '.': return( DOT );
case '=':
switch( peekc = getc() ){
case '=': c=EQ; goto gotit;
case '+': c=EQPL; goto gotit;
case '-': c=EQMI; goto gotit;
case '*': c=EQMUL; goto gotit;
case '/': c=EQDIV; goto gotit;
case '%': c=EQREM; goto gotit;
case '^': c=EQEXP; goto gotit;
default: return( '=' );
gotit: peekc = -1; return(c);
}
case '+': return( cpeek( '+', INCR, '+' ) );
case '-': return( cpeek( '-', DECR, '-' ) );
case '<': return( cpeek( '=', LE, '<' ) );
case '>': return( cpeek( '=', GE, '>' ) );
case '!': return( cpeek( '=', NE, '!' ) );
case '/':
if((peekc = getc()) == '*'){
peekc = -1;
while((getc() != '*') || ((peekc = getc()) != '/'));
peekc = -1;
goto restart;
}
else return(c);
case '"':
yylval = str;
while((c=getc()) != '"')*str++ = c;
*str++ = '\0';
return(QSTR);
default: return( c );
}
}
cpeek( c, yes, no ){
if( (peekc=getc()) != c ) return( no );
else {
peekc = -1;
return( yes );
}
}
getc(){
int ch;
loop:
ch = (peekc < 0) ? getchar() : peekc;
peekc = -1;
if(ch != '\0')return(ch);
if(++ifile > sargc){
if(ifile >= sargc+2)getout();
fin = dup(0);
goto loop;
}
close(fin);
if((fin = open(sargv[ifile],0)) >= 0)goto loop;
yyerror("cannot open input file");
}
# define b_sp_max 1500
int b_space [ b_sp_max ];
int * b_sp_nxt { b_space };
bdebug 0;
bundle(a){
int i, *p, *q;
i = nargs();
q = b_sp_nxt;
if( bdebug ) printf("bundle %d elements at %o\n", i, q );
for( p = &a; i-->0; ++p ){
if( b_sp_nxt >= & b_space[b_sp_max] ) yyerror( "bundling space exceeded" );
* b_sp_nxt++ = *p;
}
* b_sp_nxt++ = 0;
yyval = q;
return( q );
}
routput(p) int *p; {
if( bdebug ) printf("routput(%o)\n", p );
if( p >= &b_space[0] && p < &b_space[b_sp_max]){
/* part of a bundle */
while( *p != 0 ) routput( *p++ );
}
else printf( p ); /* character string */
}
output( p ) int *p; {
routput( p );
b_sp_nxt = & b_space[0];
printf( "\n" );
cp = cary;
str = string;
crs = rcrs;
}
conout( p, s ) int *p; char *s; {
printf("[");
routput( p );
printf("]s%s\n", s );
lev--;
str = string;
}
yyerror( s ) char *s; {
printf("c[%s]pc\n", s );
cp = cary;
crs = rcrs;
bindx = 0;
lev = 0;
b_sp_nxt = &b_space[0];
str = string;
}
pp( s ) char *s; {
/* puts the relevant stuff on pre and post for the letter s */
bundle( "S", s, pre );
pre = yyval;
bundle( post, "L", s, "s." );
post = yyval;
}
tp( s ) char *s; { /* same as pp, but for temps */
bundle( "0S", s, pre );
pre = yyval;
bundle( post, "L", s, "s." );
post = yyval;
}
yyinit(argc,argv) int argc; char *argv[];{
int (*getout)();
signal( 2, getout ); /* ignore all interrupts */
sargv=argv;
sargc= -- argc;
if(sargc == 0)fin=dup(0);
else if((fin = open(sargv[1],0)) < 0)
yyerror("cannot open input file");
ifile = 1;
}
getout(){
printf("q");
exit();
}
getf(p) char *p;{
return(&funtab[*p -0141]);
}
geta(p) char *p;{
return(&atab[*p - 0141]);
}
main(argc, argv)
char **argv;
{
int p[2];
if (argc > 1 && *argv[1] == '-') {
if(argv[1][1] == 'd'){
yyinit(--argc, ++argv);
yyparse();
exit();
}
if(argv[1][1] != 'l'){
printf("unrecognizable argument\n");
exit();
}
argv[1] = "/usr/lib/lib.b";
}
pipe(p);
if (fork()==0) {
close(1);
dup(p[1]);
close(p[0]);
close(p[1]);
yyinit(argc, argv);
yyparse();
exit();
}
close(0);
dup(p[0]);
close(p[0]);
close(p[1]);
execl("/bin/dc", "dc", "-", 0);
}