feat: working parser for rc shell language

1 files changed, 356 insertions, 0 deletions

diff --git a/sys/cmd/rc/code.c b/sys/cmd/rc/code.c
new file mode 100644
index 0000000..f38dd43
--- /dev/null
+++ b/sys/cmd/rc/code.c
@@ -0,0 +1,356 @@
+#include "rc.h"
+
+#define delcode   100
+#define	c0	      t->child[0]
+#define	c1	      t->child[1]
+#define	c2	      t->child[2]
+
+#define	emitf(x) ((code.ip!=code.end || morecode()), code.ip++->f = (x))
+#define	emiti(x) ((code.ip!=code.end || morecode()), code.ip++->i = (x))
+#define	emits(x) ((code.ip!=code.end || morecode()), code.ip++->s = (x))
+
+static struct 
+{
+    int   cap;
+    Code *buf, *ip, *end;
+} code;
+
+static
+int
+morecode(void)
+{
+    code.cap += delcode;
+    code.buf  = erealloc(code.buf, code.cap*sizeof(*code.buf));
+    code.end  = code.ip + delcode;
+    memset(code.ip, 0, delcode*sizeof(*code.buf));
+
+    return 0;
+}
+
+static
+void
+stuffdot(Code *p)
+{
+    int a;
+
+    a = p - code.buf;
+    if (code.ip <= p || p < code.buf)
+        panic("bad address %d in stuffdot", a);
+    codebuf[a].i = code.ip-code.buf;
+}
+
+static
+void
+rcc(Tree *t, int eflag)
+{
+    Code *p, *q;
+    Tree *tt;
+
+    if (!t)
+        return;
+
+    switch(t->type) {
+    default:
+		pfmt(errio, "bad type %d in rc compiler\n", t->type);
+		break;
+	case '$':
+		emitf(Xmark);
+		rcc(c0, eflag);
+		emitf(Xdol);
+		break;
+	case '"':
+		emitf(Xmark);
+		rcc(c0, eflag);
+		emitf(Xqdol);
+		break;
+	case Asub:
+		emitf(Xmark);
+		rcc(c0, eflag);
+		emitf(Xmark);
+		rcc(c1, eflag);
+		emitf(Xsub);
+		break;
+	case '&':
+		emitf(Xasync);
+		if(havefork){
+			p = emiti(0);
+			rcc(c0, eflag);
+			emitf(Xexit);
+			stuffdot(p);
+		} else
+			emits(fnstr(c0));
+		break;
+	case ';':
+		rcc(c0, eflag);
+		rcc(c1, eflag);
+		break;
+	case '^':
+		emitf(Xmark);
+		rcc(c1, eflag);
+		emitf(Xmark);
+		rcc(c0, eflag);
+		emitf(Xconc);
+		break;
+	case '`':
+		emitf(Xbackq);
+		if(havefork){
+			p = emiti(0);
+			rcc(c0, 0);
+			emitf(Xexit);
+			stuffdot(p);
+		} else
+			emits(fnstr(c0));
+		break;
+	case Aandand:
+		rcc(c0, 0);
+		emitf(Xtrue);
+		p = emiti(0);
+		rcc(c1, eflag);
+		stuffdot(p);
+		break;
+	case Aargs:
+		rcc(c1, eflag);
+		rcc(c0, eflag);
+		break;
+	case Kbang:
+		rcc(c0, eflag);
+		emitf(Xbang);
+		break;
+	case Aparen:
+	case Abrace:
+		rcc(c0, eflag);
+		break;
+	case Acount:
+		emitf(Xmark);
+		rcc(c0, eflag);
+		emitf(Xcount);
+		break;
+	case Kfunc:
+		emitf(Xmark);
+		rcc(c0, eflag);
+		if(c1){
+			emitf(Xfn);
+			p = emiti(0);
+			emits(fnstr(c1));
+			rcc(c1, eflag);
+			emitf(Xunlocal);	/* get rid of $* */
+			emitf(Xreturn);
+			stuffdot(p);
+		}
+		else
+			emitf(Xdelfn);
+		break;
+	case Kif:
+		rcc(c0, 0);
+		emitf(Xif);
+		p = emiti(0);
+		rcc(c1, eflag);
+		emitf(Xwastrue);
+		stuffdot(p);
+		break;
+	case Kelse:
+		if(!runq->iflast)
+			error("`else' does not follow `if(...)'");
+		emitf(Xelse);
+		p = emiti(0);
+		rcc(c0, eflag);
+		stuffdot(p);
+		break;
+	case Aoror:
+		rcc(c0, 0);
+		emitf(Xfalse);
+		p = emiti(0);
+		rcc(c1, eflag);
+		stuffdot(p);
+		break;
+	case Aparen:
+		rcc(c0, eflag);
+		break;
+	case Asimple:
+		emitf(Xmark);
+		rcc(c0, eflag);
+		emitf(Xsimple);
+		if(eflag)
+			emitf(Xeflag);
+		break;
+	case Ksubsh:
+		emitf(Xsubshell);
+		if(havefork){
+			p = emiti(0);
+			rcc(c0, eflag);
+			emitf(Xexit);
+			stuffdot(p);
+		} else
+			emits(fnstr(c0));
+		if(eflag)
+			emitf(Xeflag);
+		break;
+	case Kswitch:
+		codeswitch(t, eflag);
+		break;
+	case Ktwiddle:
+		emitf(Xmark);
+		rcc(c1, eflag);
+		emitf(Xmark);
+		rcc(c0, eflag);
+		emitf(Xmatch);
+		if(eflag)
+			emitf(Xeflag);
+		break;
+	case Kwhile:
+		q = code.ip;
+		rcc(c0, 0);
+		if(q==code.ip)
+			emitf(Xsettrue);	/* empty condition == while(true) */
+		emitf(Xtrue);
+		p = emiti(0);
+		rcc(c1, eflag);
+		emitf(Xjump);
+		emiti(q);
+		stuffdot(p);
+		break;
+	case Awords:
+		rcc(c1, eflag);
+		rcc(c0, eflag);
+		break;
+	case Kfor:
+		emitf(Xmark);
+		if(c1){
+			rcc(c1, eflag);
+			emitf(Xglob);
+		}
+		else{
+			emitf(Xmark);
+			emitf(Xword);
+			emits(strdup("*"));
+			emitf(Xdol);
+		}
+		emitf(Xmark);		/* dummy value for Xlocal */
+		emitf(Xmark);
+		rcc(c0, eflag);
+		emitf(Xlocal);
+		p = emitf(Xfor);
+		q = emiti(0);
+		rcc(c2, eflag);
+		emitf(Xjump);
+		emiti(p-code.buf);
+		stuffdot(q);
+		emitf(Xunlocal);
+		break;
+	case Aword:
+		emitf(Xword);
+		emits(strdup(t->str));
+		break;
+	case Adup:
+		if(t->rtype==Adupfd){
+			emitf(Xdup);
+			emiti(t->fd0);
+			emiti(t->fd1);
+		}
+		else{
+			emitf(Xclose);
+			emiti(t->fd0);
+		}
+		rcc(c1, eflag);
+		emitf(Xpopredir);
+		break;
+	case Apipefd:
+		emitf(Xpipefd);
+		emiti(t->rtype);
+		if(havefork){
+			p = emiti(0);
+			rcc(c0, eflag);
+			emitf(Xexit);
+			stuffdot(p);
+		} else {
+			emits(fnstr(c0));
+		}
+		break;
+	case Aredir:
+		emitf(Xmark);
+		rcc(c0, eflag);
+		emitf(Xglob);
+		switch(t->rtype){
+		case Rappend:
+			emitf(Xappend);
+			break;
+		case Rwrite:
+			emitf(Xwrite);
+			break;
+		case Rread:
+		case Rhere:
+			emitf(Xread);
+			break;
+		case Rrdwr:
+			emitf(Xrdwr);
+			break;
+		}
+		emiti(t->fd0);
+		rcc(c1, eflag);
+		emitf(Xpopredir);
+		break;
+	case '=':
+		tt = t;
+		for(;t && t->type=='=';t = c2);
+		if(t){
+			for(t = tt;t->type=='=';t = c2){
+				emitf(Xmark);
+				rcc(c1, eflag);
+				emitf(Xmark);
+				rcc(c0, eflag);
+				emitf(Xlocal);
+			}
+			rcc(t, eflag);
+			for(t = tt; t->type=='='; t = c2)
+				emitf(Xunlocal);
+		}
+		else{
+			for(t = tt;t;t = c2){
+				emitf(Xmark);
+				rcc(c1, eflag);
+				emitf(Xmark);
+				rcc(c0, eflag);
+				emitf(Xassign);
+			}
+		}
+		t = tt;	/* so tests below will work */
+		break;
+	case Apipe:
+		emitf(Xpipe);
+		emiti(t->fd0);
+		emiti(t->fd1);
+		if(havefork){
+			p = emiti(0);
+			q = emiti(0);
+			rcc(c0, eflag);
+			emitf(Xexit);
+			stuffdot(p);
+		} else {
+			emits(fnstr(c0));
+			q = emiti(0);
+		}
+		rcc(c1, eflag);
+		emitf(Xreturn);
+		stuffdot(q);
+		emitf(Xpipewait);
+		break;
+	}
+	if(t->type!=Kelse && t->type!=';')
+		runq->iflast = t->type==IF;
+	else if(c0) runq->iflast = c0->type==IF;
+}
+
+Code*
+compile(Tree *t)
+{
+    code.cap = delcode;
+    code.buf = code.ip = emalloc(code.cap*sizeof *code.buf);
+    code.end = code.ip + code.cap;
+
+    emiti(0);
+    rcc(t, 0);
+    emitf(Xreturn);
+    emitf(nil);
+
+    return code.buf;
+}