minnie.tuhs.org/unixen.tar/unixen/PDP-11/Trees/V7/usr/src/cmd/sh/macro.c

C/C++ Source or Header | 1979-01-12 | 4.0 KB | 234 lines

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

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

LOCAL CHAR    quote;    /* used locally */
LOCAL CHAR    quoted;    /* used locally */



LOCAL STRING    copyto(endch)
    REG CHAR    endch;
{
    REG CHAR    c;

    WHILE (c=getch(endch))!=endch ANDF c
    DO pushstak(c|quote) OD
    zerostak();
    IF c!=endch THEN error(badsub) FI
}

LOCAL    skipto(endch)
    REG CHAR    endch;
{
    /* skip chars up to } */
    REG CHAR    c;
    WHILE (c=readc()) ANDF c!=endch
    DO    SWITCH c IN

        case SQUOTE:    skipto(SQUOTE); break;

        case DQUOTE:    skipto(DQUOTE); break;

        case DOLLAR:    IF readc()==BRACE
                THEN    skipto('}');
                FI
        ENDSW
    OD
    IF c!=endch THEN error(badsub) FI
}

LOCAL    getch(endch)
    CHAR        endch;
{
    REG CHAR    d;

retry:
    d=readc();
    IF !subchar(d)
    THEN    return(d);
    FI
    IF d==DOLLAR
    THEN    REG INT    c;
        IF (c=readc(), dolchar(c))
        THEN    NAMPTR        n=NIL;
            INT        dolg=0;
            BOOL        bra;
            REG STRING    argp, v;
            CHAR        idb[2];
            STRING        id=idb;

            IF bra=(c==BRACE) THEN c=readc() FI
            IF letter(c)
            THEN    argp=relstak();
                WHILE alphanum(c) DO pushstak(c); c=readc() OD
                zerostak();
                n=lookup(absstak(argp)); setstak(argp);
                v = n->namval; id = n->namid;
                peekc = c|MARK;;
            ELIF digchar(c)
            THEN    *id=c; idb[1]=0;
                IF astchar(c)
                THEN    dolg=1; c='1';
                FI
                c -= '0';
                v=((c==0) ? cmdadr : (c<=dolc) ? dolv[c] : (dolg=0));
            ELIF c=='$'
            THEN    v=pidadr;
            ELIF c=='!'
            THEN    v=pcsadr;
            ELIF c=='#'
            THEN    v=dolladr;
            ELIF c=='?'
            THEN    v=exitadr;
            ELIF c=='-'
            THEN    v=flagadr;
            ELIF bra THEN error(badsub);
            ELSE    goto retry;
            FI
            c = readc();
            IF !defchar(c) ANDF bra
            THEN    error(badsub);
            FI
            argp=0;
            IF bra
            THEN    IF c!='}'
                THEN    argp=relstak();
                    IF (v==0)NEQ(setchar(c))
                    THEN    copyto('}');
                    ELSE    skipto('}');
                    FI
                    argp=absstak(argp);
                FI
            ELSE    peekc = c|MARK; c = 0;
            FI
            IF v
            THEN    IF c!='+'
                THEN    LOOP WHILE c = *v++
                         DO pushstak(c|quote); OD
                         IF dolg==0 ORF (++dolg>dolc)
                         THEN break;
                         ELSE v=dolv[dolg]; pushstak(SP|(*id=='*' ? quote : 0));
                         FI
                    POOL
                FI
            ELIF argp
            THEN    IF c=='?'
                THEN    failed(id,*argp?argp:badparam);
                ELIF c=='='
                THEN    IF n
                    THEN    assign(n,argp);
                    ELSE    error(badsub);
                    FI
                FI
            ELIF flags&setflg
            THEN    failed(id,badparam);
            FI
            goto retry;
        ELSE    peekc=c|MARK;
        FI
    ELIF d==endch
    THEN    return(d);
    ELIF d==SQUOTE
    THEN    comsubst(); goto retry;
    ELIF d==DQUOTE
    THEN    quoted++; quote^=QUOTE; goto retry;
    FI
    return(d);
}

STRING    macro(as)
    STRING        as;
{
    /* Strip "" and do $ substitution
     * Leaves result on top of stack
     */
    REG BOOL    savqu =quoted;
    REG CHAR    savq = quote;
    FILEHDR        fb;

    push(&fb); estabf(as);
    usestak();
    quote=0; quoted=0;
    copyto(0);
    pop();
    IF quoted ANDF (stakbot==staktop) THEN pushstak(QUOTE) FI
    quote=savq; quoted=savqu;
    return(fixstak());
}

LOCAL    comsubst()
{
    /* command substn */
    FILEBLK        cb;
    REG CHAR    d;
    REG STKPTR    savptr = fixstak();

    usestak();
    WHILE (d=readc())!=SQUOTE ANDF d
    DO pushstak(d) OD

    BEGIN
       REG STRING    argc;
       trim(argc=fixstak());
       push(&cb); estabf(argc);
    END
    BEGIN
       REG TREPTR    t = makefork(FPOU,cmd(EOFSYM,MTFLG|NLFLG));
       INT        pv[2];

       /* this is done like this so that the pipe
        * is open only when needed
        */
       chkpipe(pv);
       initf(pv[INPIPE]);
       execute(t, 0, 0, pv);
       close(pv[OTPIPE]);
    END
    tdystak(savptr); staktop=movstr(savptr,stakbot);
    WHILE d=readc() DO pushstak(d|quote) OD
    await(0);
    WHILE stakbot!=staktop
    DO    IF (*--staktop&STRIP)!=NL
        THEN    ++staktop; break;
        FI
    OD
    pop();
}

#define CPYSIZ    512

subst(in,ot)
    INT        in, ot;
{
    REG CHAR    c;
    FILEBLK        fb;
    REG INT        count=CPYSIZ;

    push(&fb); initf(in);
    /* DQUOTE used to stop it from quoting */
    WHILE c=(getch(DQUOTE)&STRIP)
    DO pushstak(c);
       IF --count == 0
       THEN    flush(ot); count=CPYSIZ;
       FI
    OD
    flush(ot);
    pop();
}

LOCAL    flush(ot)
{
    write(ot,stakbot,staktop-stakbot);
    IF flags&execpr THEN write(output,stakbot,staktop-stakbot) FI
    staktop=stakbot;
}