BSD 3 development

[unix-history] / usr / src / cmd / sh / word.c

#
/*
* UNIX shell
*
* S. R. Bourne
* Bell Telephone Laboratories
*
*/

#include        "defs.h"
#include        "sym.h"


/* ========     character handling for command lines    ========*/


word()
{
       REG CHAR        c, d;
       REG CHAR        *argp=locstak()+BYTESPERWORD;
       INT             alpha=1;

       wdnum=0; wdset=0;

       WHILE (c=nextc(0), space(c)) DONE
       IF !eofmeta(c)
       THEN    REP     IF c==LITERAL
                       THEN    *argp++=(DQUOTE);
                               WHILE (c=readc()) ANDF c!=LITERAL
                               DO *argp++=(c|QUOTE); chkpr(c) OD
                               *argp++=(DQUOTE);
                       ELSE    *argp++=(c);
                               IF c=='=' THEN wdset |= alpha FI
                               IF !alphanum(c) THEN alpha=0 FI
                               IF qotchar(c)
                               THEN    d=c;
                                       WHILE (*argp++=(c=nextc(d))) ANDF c!=d
                                       DO chkpr(c) OD
                               FI
                       FI
               PER (c=nextc(0), !eofmeta(c)) DONE
               argp=endstak(argp);
               IF !letter(argp->argval[0]) THEN wdset=0 FI

               peekc=c|MARK;
               IF argp->argval[1]==0 ANDF (d=argp->argval[0], digit(d)) ANDF (c=='>' ORF c=='<')
               THEN    word(); wdnum=d-'0';
               ELSE    /*check for reserved words*/
                       IF reserv==FALSE ORF (wdval=syslook(argp->argval,reserved))==0
                       THEN    wdarg=argp; wdval=0;
                       FI
               FI

       ELIF dipchar(c)
       THEN    IF (d=nextc(0))==c
               THEN    wdval = c|SYMREP;
               ELSE    peekc = d|MARK; wdval = c;
               FI
       ELSE    IF (wdval=c)==EOF
               THEN    wdval=EOFSYM;
               FI
               IF iopend ANDF eolchar(c)
               THEN    copy(iopend); iopend=0;
               FI
       FI
       reserv=FALSE;
       return(wdval);
}

nextc(quote)
       CHAR            quote;
{
       REG CHAR        c, d;
       IF (d=readc())==ESCAPE
       THEN    IF (c=readc())==NL
               THEN    chkpr(NL); d=nextc(quote);
               ELIF quote ANDF c!=quote ANDF !escchar(c)
               THEN    peekc=c|MARK;
               ELSE    d = c|QUOTE;
               FI
       FI
       return(d);
}

readc()
{
       REG CHAR        c;
       REG INT         len;
       REG FILE        f;

retry:
       IF peekc
       THEN    c=peekc; peekc=0;
       ELIF (f=standin, f->fnxt!=f->fend)
       THEN    IF (c = *f->fnxt++)==0
               THEN    IF f->feval
                       THEN    IF estabf(*f->feval++)
                               THEN    c=EOF;
                               ELSE    c=SP;
                               FI
                       ELSE    goto retry; /* = c=readc(); */
                       FI
               FI
               IF flags&readpr ANDF standin->fstak==0 THEN prc(c) FI
               IF c==NL THEN f->flin++ FI
       ELIF f->feof ORF f->fdes<0
       THEN    c=EOF; f->feof++;
       ELIF (len=readb())<=0
       THEN    close(f->fdes); f->fdes = -1; c=EOF; f->feof++;
       ELSE    f->fend = (f->fnxt = f->fbuf)+len;
               goto retry;
       FI
       return(c);
}

LOCAL   readb()
{
       REG FILE        f=standin;
       REG INT         len;

       REP     IF trapnote&SIGSET THEN newline(); sigchk() FI
       PER (len=read(f->fdes,f->fbuf,f->fsiz))<0 ANDF trapnote DONE
       return(len);
}