source: mainline/uspace/app/pcc/f77/fcom/gram.io@ e4f8c77

  /*  Input/Output Statements */

io:       io1
                { endio(); }
        ;

io1:      iofmove ioctl
        | iofmove unpar_fexpr
                { ioclause(IOSUNIT, $2); endioctl(); }
        | iofctl ioctl
        | read ioctl
                { doio(NULL); }
        | read ioctl inlist
                { doio($3); }
        | read infmt SCOMMA inlist
                { doio($4); }
        | read ioctl SCOMMA inlist
                { doio($4); }
        | write ioctl
                { doio(NULL); }
        | write ioctl outlist
                { doio($3); }
        | print
                { doio(NULL); }
        | print SCOMMA outlist
                { doio($3); }
        ;

iofmove:   fmkwd end_spec in_ioctl
        ;

fmkwd:    SBACKSPACE
                { iostmt = IOREWIND; }
        | SREWIND
                { iostmt = IOREWIND; }
        | SENDFILE
                { iostmt = IOENDFILE; }
        ;

iofctl:  ctlkwd end_spec in_ioctl
        ;

ctlkwd:   SINQUIRE
                { iostmt = IOINQUIRE; }
        | SOPEN
                { iostmt = IOOPEN; }
        | SCLOSE
                { iostmt = IOCLOSE; }
        ;

infmt:    unpar_fexpr
                {
                ioclause(IOSUNIT, NULL);
                ioclause(IOSFMT, $1);
                endioctl();
                }
        | SSTAR
                {
                ioclause(IOSUNIT, NULL);
                ioclause(IOSFMT, NULL);
                endioctl();
                }
        ;

ioctl:    SLPAR fexpr SRPAR
                { ioclause(IOSUNIT, $2); endioctl(); }
        | SLPAR ctllist SRPAR
                { endioctl(); }
        ;

ctllist:  ioclause SCOMMA ioclause
        | ctllist SCOMMA ioclause
        ;

ioclause:  fexpr
                { ioclause(IOSPOSITIONAL, $1); }
        | SSTAR
                { ioclause(IOSPOSITIONAL, NULL); }
        | nameeq expr
                { ioclause($1, $2); }
        | nameeq SSTAR
                { ioclause($1, NULL); }
        ;

nameeq:  SNAMEEQ
                { $$ = iocname(); }
        ;

read:     SREAD end_spec in_ioctl
                { iostmt = IOREAD; }
        ;

write:    SWRITE end_spec in_ioctl
                { iostmt = IOWRITE; }
        ;

print:    SPRINT end_spec fexpr in_ioctl
                {
                iostmt = IOWRITE;
                ioclause(IOSUNIT, NULL);
                ioclause(IOSFMT, $3);
                endioctl();
                }
        | SPRINT end_spec SSTAR in_ioctl
                {
                iostmt = IOWRITE;
                ioclause(IOSUNIT, NULL);
                ioclause(IOSFMT, NULL);
                endioctl();
                }
        ;

inlist:   inelt
                { $$ = mkchain($1,0); }
        | inlist SCOMMA inelt
                { $$ = hookup($1, mkchain($3,0)); }
        ;

inelt:    lhs
        | SLPAR inlist SCOMMA dospec SRPAR
                { $$ = mkiodo($4,$2); }
        ;

outlist:  uexpr
                { $$ = mkchain($1, 0); }
        | other
                { $$ = mkchain($1, 0); }
        | out2
        ;

out2:     uexpr SCOMMA uexpr
                { $$ = mkchain($1, mkchain($3, 0) ); }
        | uexpr SCOMMA other
                { $$ = mkchain($1, mkchain($3, 0) ); }
        | other SCOMMA uexpr
                { $$ = mkchain($1, mkchain($3, 0) ); }
        | other SCOMMA other
                { $$ = mkchain($1, mkchain($3, 0) ); }
        | out2  SCOMMA uexpr
                { $$ = hookup($1, mkchain($3, 0) ); }
        | out2  SCOMMA other
                { $$ = hookup($1, mkchain($3, 0) ); }
        ;

other:    complex_const
        | SLPAR uexpr SCOMMA dospec SRPAR
                { $$ = mkiodo($4, mkchain($2, 0) ); }
        | SLPAR other SCOMMA dospec SRPAR
                { $$ = mkiodo($4, mkchain($2, 0) ); }
        | SLPAR out2  SCOMMA dospec SRPAR
                { $$ = mkiodo($4, $2); }
        ;

in_ioctl:
                { startioctl(); }
        ;