Add work in progress concurrency. Might break stuff!

14 files changed, 330 insertions, 61 deletions

diff --git a/apl9.h b/apl9.h
index 77966ed..4c28315 100644
--- a/apl9.h
+++ b/apl9.h
@@ -70,6 +70,8 @@ typedef struct Symtab Symtab;
 typedef struct QuadnameDef QuadnameDef;
 typedef struct ErrorHandler ErrorHandler;
 typedef struct DfnFrame DfnFrame;
+typedef struct ThreadData ThreadData;
+typedef struct Mail Mail;
 
 struct Mixed
 {
@@ -204,6 +206,22 @@ struct DfnFrame
 	DfnFrame *prev;
 };
 
+struct ThreadData
+{
+	int id;
+	DfnFrame *currentdfn;
+	Mail *mail;
+	Mail *lastmail;
+	QLock lock;
+	Rendez empty;
+};
+
+struct Mail
+{
+	Array *contents;
+	Mail *next;
+};
+
 /* Function prototypes for the different source files */
 /* main.c */
 Datum *evalline(Rune *, Biobuf *, int);
@@ -259,7 +277,7 @@ void checkmem(char *);
 
 Array *allocarray(int, int, int);
 void freearray(Array *);
-void incref(Array *);
+void incarrayref(Array *);
 
 /* functions.c */
 Array *runfunc(Function, Array *,Array *);
@@ -283,6 +301,13 @@ void throwerror(Rune *, int);
 /* inverse.c */
 Function inverse(Function);
 
+/* concurrency.c */
+void initthreads(void);
+int spawnthread(Function, Array *, Array *);
+ThreadData *getthreaddata(void);
+void messagesend(Array *, int);
+Array *messagerecv(Function, int);
+
 /* Monadic functions from function.c */
 Array *fnNegate(Array *);
 Array *fnSign(Array *);
@@ -369,13 +394,16 @@ Array *fnReshape(Array *, Array *);
 Array *fnRotateLast(Array *, Array *);
 Array *fnRotateFirst(Array *, Array *);
 Array *fnSelfReference2(Array *, Array *);
+Array *fnSend(Array *, Array *);
 
 /* Monadic operators from operators.c */
 Array *opEach(Datum *, Array *, Array *);
 Array *opSwitch(Datum *, Array *, Array *);
 Array *opKey(Datum *, Array *, Array *);
+Array *opSpawn(Datum *, Array *, Array *);
 Array *opOuterProduct(Datum *, Array *, Array *);
 Array *opSelfReference1(Datum *, Array *, Array *);
+Array *opReceive(Datum *, Array *, Array *);
 
 /* Dyadic operators from operators.c */
 Array *opPower(Datum *, Datum *, Array *, Array *);
@@ -419,4 +447,5 @@ extern QuadnameDef quadnames[]; /* quadnames.c */
 extern int printprecision; /* print.c */
 extern ErrorHandler globalerror; /* error.c */
 extern Rune *errorstrs[]; /* error.c */
-extern int needsnewline; /* quadnames.c */
\ No newline at end of file
+extern int needsnewline; /* quadnames.c */
+extern int mainstacksize; /* concurrency.c */
\ No newline at end of file
diff --git a/array.c b/array.c
index c29c411..bc00a89 100644
--- a/array.c
+++ b/array.c
@@ -55,7 +55,7 @@ duparray(Array *a)
 	memcpy(b->rawdata, a->rawdata, datasizes[a->type]*a->size);
 	if(b->type == AtypeArray)
 		for(int i = 0; i < b->size; i++)
-			incref(b->arraydata[i]);
+			incarrayref(b->arraydata[i]);
 	return b;
 }
 
@@ -197,7 +197,7 @@ arrayitem(Array *a, int index)
 		break;
 	case AtypeArray:
 		res = a->arraydata[index];
-		incref(res);
+		incarrayref(res);
 		break;
 	default:
 		throwerror(L"Unhandled case in arrayitem", ENotImplemented);
@@ -233,7 +233,7 @@ simplifyarray(Array *a)
 			if(nested){
 				memcpy(b->rawdata + i * datasizes[type], a->arraydata[i]->rawdata, datasizes[type]);
 				if(b->type == AtypeArray)
-					incref(b->arraydata[i]);
+					incarrayref(b->arraydata[i]);
 			}else{
 				switch(b->type){
 				case AtypeInt: b->intdata[i] = a->mixeddata[i].i; break;
diff --git a/concurrency.c b/concurrency.c
new file mode 100644
index 0000000..4af563c
--- /dev/null
+++ b/concurrency.c
@@ -0,0 +1,148 @@
+#include <u.h>
+#include <libc.h>
+#include <thread.h>
+#include <bio.h>
+#include "apl9.h"
+
+#define STACKSIZE (8*1024*1024) /* 8 MB */
+
+typedef struct SpawnData SpawnData;
+struct SpawnData
+{
+	Function func;
+	Array *left;
+	Array *right;
+	Channel *setupdone;
+};
+
+static void newprocfn(void *);
+static ThreadData *newthreaddata(void);
+
+/* global data */
+static Lock threadlock;
+static int nthreads;
+static ThreadData **threads;
+int mainstacksize = STACKSIZE;
+
+void
+initthreads(void)
+{
+	ThreadData *td = newthreaddata();
+	void **tdptr = threaddata();
+	*tdptr = td;
+}
+
+int
+spawnthread(Function f, Array *left, Array *right)
+{
+	/* lock the data structures */
+	/* Spawn a new proc */
+	/* Allocate a new mailbox */
+	/* Send a message back to spawnthread that the setup is ready */
+	/* In spawnthread: unlock datastructures, return thread id */
+	/* in new proc:
+		run runfunc
+		lock datastructures
+		delete mailbox
+		unlock datastructures
+		exit proc
+	*/
+	Channel *setupdone = chancreate(sizeof(int), 0);
+	SpawnData *sp = malloc(sizeof(SpawnData));
+	sp->func = f;
+	sp->left = left ? duparray(left) : nil;
+	sp->right = duparray(right);
+	sp->setupdone = setupdone;
+	int id = proccreate(newprocfn, sp, STACKSIZE);
+	recv(setupdone, nil); /* wait for new proc to signal that the setup is done */
+	chanfree(setupdone);
+	return id;
+}
+
+ThreadData *
+getthreaddata(void)
+{
+	void **tdptr = threaddata();
+	return (ThreadData *)*tdptr;
+}
+
+void
+messagesend(Array *a, int id)
+{
+	ThreadData *td = nil;
+	lock(&threadlock);
+	for(int i = 0; i < nthreads && td == nil; i++)
+		if(threads[i]->id == id)
+			td = threads[i];
+	unlock(&threadlock);
+	if(td != nil){
+		qlock(&td->lock);
+		Mail *newmail = malloc(sizeof(Mail));
+		newmail->contents = fnSame(a);
+		newmail->next = 0;
+		if(td->lastmail != nil)
+			td->lastmail->next = newmail;
+		else
+			td->mail = newmail;
+		td->lastmail = newmail;
+		rwakeup(&td->empty);
+		qunlock(&td->lock);
+	}
+}
+
+Array *
+messagerecv(Function match, int timeout)
+{
+	USED(timeout);
+	USED(match);
+	ThreadData *td = getthreaddata();
+	qlock(&td->lock);
+	while(td->mail == nil)
+		rsleep(&td->empty);
+	Mail *m = td->mail;
+	td->mail = m->next;
+	if(td->mail == nil)
+		td->lastmail = nil;
+	qunlock(&td->lock);
+	Array *a = m->contents;
+	free(m);
+	return a;
+}
+
+
+static void
+newprocfn(void *data)
+{
+	SpawnData *sp = (SpawnData *)data;
+	ThreadData *td = newthreaddata();
+	void **tdptr = threaddata();
+	*tdptr = td;
+	int done = 1;
+	send(sp->setupdone, &done);
+	runfunc(sp->func, sp->left, sp->right);
+	lock(&threadlock);
+	/* TODO remove thread */
+	unlock(&threadlock);
+	freearray(sp->left);
+	freearray(sp->right);
+	free(sp);
+	free(td);
+}
+
+static ThreadData *
+newthreaddata(void)
+{
+	ThreadData *td = mallocz(sizeof(ThreadData), 1);
+	td->id = threadid();
+	td->currentdfn = nil;
+	td->mail = 0;
+	td->lastmail = 0;
+	td->empty.l = &td->lock;
+
+	lock(&threadlock);
+	nthreads++;
+	threads = realloc(threads, sizeof(ThreadData *) * nthreads);
+	threads[nthreads-1] = td;
+	unlock(&threadlock);
+	return td;
+}
diff --git a/error.c b/error.c
index 2d69457..47837a9 100644
--- a/error.c
+++ b/error.c
@@ -1,5 +1,6 @@
 #include <u.h>
 #include <libc.h>
+#include <thread.h>
 #include <bio.h>
 
 #include "apl9.h"
diff --git a/eval.c b/eval.c
index c6f6a8d..1d54e42 100644
--- a/eval.c
+++ b/eval.c
@@ -150,7 +150,7 @@ lookup(Datum var)
 	else{
 		val = &symbol->value;
 		if(val->tag == ArrayTag)
-			incref(val->array); /* since the value is now in the var AND in the code */
+			incarrayref(val->array); /* since the value is now in the var AND in the code */
 	}
 	val->shy = 0;
 	traceprint("VAR %S = %S\n", var.name, ppdatum(*val));
@@ -200,7 +200,7 @@ dyadfun(Datum left, Datum right)
 		result.func.code = right.hybrid;
 	}
 	result.func.left = left.array;
-	incref(left.array);
+	incarrayref(left.array);
 	return result;
 }
 
@@ -261,7 +261,7 @@ assign(Datum left, Datum right)
 			symbol->undefined = 0;
 			if(symbol->value.tag == ArrayTag){
 				symbol->value.array->stranded = 0;
-				incref(right.array); /* for the binding */
+				incarrayref(right.array); /* for the binding */
 			}
 		}
 	}else{
@@ -307,7 +307,7 @@ assign(Datum left, Datum right)
 	}
 	right.shy = 1;
 	if(right.tag == ArrayTag)
-		incref(right.array); /* for the returned array */
+		incarrayref(right.array); /* for the returned array */
 	return right;
 }
 
@@ -331,7 +331,7 @@ monadop(Datum left, Datum right)
 	result.func.operator.left = arg;
 	result.func.left = nil;
 	if(arg->tag == ArrayTag)
-		incref(arg->array);
+		incarrayref(arg->array);
 	return result;
 }
 
@@ -348,7 +348,7 @@ dyadop(Datum left, Datum right)
 	result.operator = left.operator;
 	result.operator.right = arg;
 	if(arg->tag == ArrayTag)	
-		incref(arg->array);
+		incarrayref(arg->array);
 	return result;
 }
 
diff --git a/functions.c b/functions.c
index b1003fa..46f9782 100644
--- a/functions.c
+++ b/functions.c
@@ -4,7 +4,7 @@
 
 #include "apl9.h"
 
-Rune primfuncnames[] = L"+-×÷*⍟⌹○!?|⌈⌊⊥⊤⊣⊢=≠≤<>≥≡≢∨∧⍲⍱↑↓⊂⊃⊆⌷⍋⍒⍳⍸∊⍷∪∩~,⍪⍴⌽⊖⍉⍎⍕∇";
+Rune primfuncnames[] = L"+-×÷*⍟⌹○!?|⌈⌊⊥⊤⊣⊢=≠≤<>≥≡≢∨∧⍲⍱↑↓⊂⊃⊆⌷⍋⍒⍳⍸∊⍷∪∩~,⍪⍴⌽⊖⍉⍎⍕∇⍈";
 
 fnmonad monadfunctiondefs[] = {
 	fnSame, /* + */
@@ -60,6 +60,7 @@ fnmonad monadfunctiondefs[] = {
 	fnExecute, /* ⍎ */
 	fnFormat, /* ⍕ */
 	fnSelfReference1, /* ∇ */
+	0, /* ⍈ */
 };
 
 fndyad dyadfunctiondefs[] = {
@@ -116,6 +117,7 @@ fndyad dyadfunctiondefs[] = {
 	0, /* ⍎ */
 	0, /* ⍕ */
 	fnSelfReference2, /* ∇ */
+	fnSend, /* ⍈ */
 };
 
 vlong gcd_int(vlong, vlong);
@@ -445,7 +447,7 @@ fnFloor(Array *right)
 Array *
 fnSame(Array *right)
 {
-	incref(right);
+	incarrayref(right);
 	return right;
 }
 
@@ -533,10 +535,10 @@ fnMix(Array *right)
 				result->arraydata[i*commonsize] = a->arraydata[0];
 			else
 				result->arraydata[i*commonsize] = a;
-			incref(result->arraydata[i*commonsize]);
+			incarrayref(result->arraydata[i*commonsize]);
 			for(j = 1; j < commonsize; j++){
 				result->arraydata[i*commonsize+j] = fill;
-				incref(fill);
+				incarrayref(fill);
 			}
 		}else{
 			for(j = 0; j < commonrank; j++)
@@ -546,7 +548,7 @@ fnMix(Array *right)
 					int nfill = commonshape->intdata[commonrank-1-k] - a->shape[a->rank-1-k];
 					while(nfill--){
 						result->arraydata[i*commonsize+offset] = fill;
-						incref(fill);
+						incarrayref(fill);
 						offset++;
 					}
 					index[commonrank-1-k] = 0;
@@ -558,7 +560,7 @@ fnMix(Array *right)
 					index[commonrank-1]++;
 				}else if(offset < commonsize){
 					result->arraydata[i*commonsize+offset] = fill;
-					incref(fill);
+					incarrayref(fill);
 					offset++;
 				}
 			}
@@ -580,7 +582,7 @@ fnSplit(Array *right)
 Array *
 fnEnclose(Array *right)
 {
-	incref(right);
+	incarrayref(right);
 	if(simplescalar(right))
 		return right;
 	else{
@@ -1148,7 +1150,7 @@ Array *
 fnLeft(Array *left, Array *right)
 {
 	USED(right);
-	incref(left);
+	incarrayref(left);
 	return left;
 }
 
@@ -1156,7 +1158,7 @@ Array *
 fnRight(Array *left, Array *right)
 {
 	USED(left);
-	incref(right);
+	incarrayref(right);
 	return right;
 }
 
@@ -1352,7 +1354,7 @@ fnTake(Array *left, Array *right)
 			memcpy(result->rawdata + i*datasizes[result->type],
 				fill->rawdata, datasizes[result->type]);
 		if(result->type == AtypeArray)
-			incref(result->arraydata[i]);
+			incarrayref(result->arraydata[i]);
 		index[left->size-1]++;
 	}
 
@@ -1530,7 +1532,7 @@ fnIndex(Array *left, Array *right)
 					throwerror(nil, EIndex);
 			}
 			left->arraydata[i] = oldleft->arraydata[i];
-			incref(left->arraydata[i]);
+			incarrayref(left->arraydata[i]);
 		}
 	}
 
@@ -1575,7 +1577,7 @@ fnIndex(Array *left, Array *right)
 			right->rawdata + from * datasizes[result->type],
 			datasizes[result->type]);
 		if(result->type == AtypeArray)
-			incref(result->arraydata[i]);
+			incarrayref(result->arraydata[i]);
 		leftindex[left->size-1]++;
 	}
 	free(leftindex);
@@ -1626,7 +1628,7 @@ fnFind(Array *left, Array *right)
 		memcpy(newleft->rawdata, left->rawdata, datasizes[left->type] * left->size);
 		if(left->type == AtypeArray)
 			for(i = 0; i < left->size; i++)
-				incref(newleft->arraydata[i]);
+				incarrayref(newleft->arraydata[i]);
 		left = newleft;
 	}else
 		left = fnSame(left);
@@ -1746,7 +1748,7 @@ fnCatenateFirst(Array *left, Array *right)
 	for(i = 0, j = 0; i < leftarr->size; i++, j++){
 		if(type == AtypeArray && leftarr->type == AtypeArray){
 			result->arraydata[j] = leftarr->arraydata[i];
-			incref(result->arraydata[j]);
+			incarrayref(result->arraydata[j]);
 		}else if(type == AtypeArray && leftarr->type != AtypeArray){
 			result->arraydata[j] = arrayitem(leftarr, i);
 		}else{
@@ -1761,7 +1763,7 @@ fnCatenateFirst(Array *left, Array *right)
 	for(i = 0; i < rightarr->size; i++, j++){
 		if(type == AtypeArray && rightarr->type == AtypeArray){
 			result->arraydata[j] = rightarr->arraydata[i];
-			incref(result->arraydata[j]);
+			incarrayref(result->arraydata[j]);
 		}else if(type == AtypeArray && rightarr->type != AtypeArray){
 			result->arraydata[j] = arrayitem(rightarr, i);
 		}else{
@@ -1795,7 +1797,7 @@ fnReshape(Array *left, Array *right)
 		memcpy(p, right->rawdata + (datasizes[res->type] * (i % right->size)), datasizes[res->type]);
 	if(res->type == AtypeArray)
 		for(i = 0; i < res->size; i++)
-			incref(res->arraydata[i]);
+			incarrayref(res->arraydata[i]);
 	return res;
 }
 
@@ -1862,6 +1864,17 @@ fnSelfReference2(Array *left, Array *right)
 	}
 }
 
+Array *
+fnSend(Array *left, Array *right)
+{
+	if(right->size != 1)
+		throwerror(nil, ELength);
+	if(right->type != AtypeInt)
+		throwerror(nil, EType);
+	messagesend(left, right->intdata[0]);
+	return fnSame(left);
+}
+
 /* helper functions */
 vlong
 gcd_int(vlong a, vlong b)
diff --git a/hybrids.c b/hybrids.c
index e7f7f4b..9dc0a43 100644
--- a/hybrids.c
+++ b/hybrids.c
@@ -95,7 +95,7 @@ fnReplicateFirst(Array *left, Array *right)
 		}
 		if(result->type == AtypeArray)
 			for(int j = 0; j < npos*cellsize; j++)
-				incref(result->arraydata[to*cellsize+j]);
+				incarrayref(result->arraydata[to*cellsize+j]);
 	}
 	freearray(fill);
 	freearray(left);
@@ -153,7 +153,7 @@ fnExpandFirst(Array *left, Array *right)
 		}
 		if(result->type == AtypeArray)
 			for(int j = 0; j < npos*cellsize; j++)
-				incref(result->arraydata[to*cellsize+j]);
+				incarrayref(result->arraydata[to*cellsize+j]);
 		if(right->shape[0] != 1 && !neg)
 			from++;
 	}
diff --git a/lexer.c b/lexer.c
index 6abe33e..864bb3c 100644
--- a/lexer.c
+++ b/lexer.c
@@ -1,5 +1,6 @@
 #include <u.h>
 #include <libc.h>
+#include <thread.h>
 #include <bio.h>
 
 #include "apl9.h"
diff --git a/main.c b/main.c
index ea26c6c..0520592 100644
--- a/main.c
+++ b/main.c
@@ -1,5 +1,6 @@
 #include <u.h>
 #include <libc.h>
+#include <thread.h>
 #include <bio.h>
 #include <pool.h>
 
@@ -8,10 +9,11 @@
 Biobuf *stdin;
 
 void
-main(int argc, char *argv[])
+threadmain(int argc, char *argv[])
 {
 	int off = 0;
 	stdin = Bfdopen(0, OREAD);
+	initthreads();
 	initsymtab();
 	initquadnames();
 	traceeval = 0;
@@ -101,6 +103,7 @@ evalline(Rune *line, Biobuf *bio, int toplevel)
 			free(tmp->toks);
 			free(tmp);
 		}
+
 		return nil;
 	}
 }
\ No newline at end of file
diff --git a/memory.c b/memory.c
index 04c716d..4606ef2 100644
--- a/memory.c
+++ b/memory.c
@@ -68,11 +68,11 @@ allocarray(arrayDataType t, int rank, int size)
 }
 
 void
-incref(Array *a)
+incarrayref(Array *a)
 {
 	/* print("INCREF %d->%d %S\n", a->refs, a->refs+1, pparray(a)); */
 	a->refs++;
 	if(a->type == AtypeArray)
 		for(int i = 0; i < a->size; i++)
-			incref(a->arraydata[i]);
+			incarrayref(a->arraydata[i]);
 }
\ No newline at end of file
diff --git a/mkfile b/mkfile
index 017cc1a..0c05261 100644
--- a/mkfile
+++ b/mkfile
@@ -15,6 +15,7 @@ OFILES=\
 	error.$O\
 	hybrids.$O\
 	inverse.$O\
+	concurrency.$O\
 
 HFILES=\
 	apl9.h\
diff --git a/operators.c b/operators.c
index f6066d9..a06b0d6 100644
--- a/operators.c
+++ b/operators.c
@@ -4,7 +4,7 @@
 
 #include "apl9.h"
 
-Rune primmonopnames[] = L"¨⍨⌸⌶&⌾∆";
+Rune primmonopnames[] = L"¨⍨⌸⌶&⌾∆⍇";
 Rune primdyadopnames[] = L"⍣.∘⍤⍥@⍠⌺⍢⍫⍙";
 
 opmonad monadoperatordefs[] = {
@@ -12,9 +12,10 @@ opmonad monadoperatordefs[] = {
 	opSwitch, /* ⍨ */
 	opKey, /* ⌸ */
 	0, /* ⌶ */
-	0, /* & */
+	opSpawn, /* & */
 	opOuterProduct, /* ⌾ */
 	opSelfReference1, /* ∆ */
+	opReceive, /* ⍇ */
 };
 
 opdyad dyadoperatordefs[] = {
@@ -68,7 +69,7 @@ Array *
 opSwitch(Datum *lefto, Array *left, Array *right)
 {
 	if(lefto->tag == ArrayTag){
-		incref(lefto->array);
+		incarrayref(lefto->array);
 		return lefto->array;
 	}else if(lefto->tag == FunctionTag){
 		if(left)
@@ -91,6 +92,15 @@ opKey(Datum *lefto, Array *left, Array *right)
 }
 
 Array *
+opSpawn(Datum *lefto, Array *left, Array *right)
+{
+	if(lefto->tag != FunctionTag)
+		throwerror(L"Can only spawn functions", EType);
+	int id = spawnthread(lefto->func, left, right);
+	return mkscalarint(id);
+}
+
+Array *
 opOuterProduct(Datum *lefto, Array *left, Array *right)
 {
 	if(left == nil)
@@ -140,6 +150,19 @@ opSelfReference1(Datum *lefto, Array *left, Array *right)
 	}
 }
 
+Array *
+opReceive(Datum *lefto, Array *left, Array *right)
+{
+	if(lefto->tag != FunctionTag)
+		throwerror(nil, EType);
+	if(right->type != AtypeInt)
+		throwerror(nil, EType);
+	if(right->size != 1)
+		throwerror(nil, ELength);
+	USED(left);
+	return messagerecv(lefto->func, right->intdata[0]);
+}
+
 /* Dyadic operators */
 Array *
 opPower(Datum *lefto, Datum *righto, Array *left, Array *right)
diff --git a/quadnames.c b/quadnames.c
index 5632cd4..7d5884c 100644
--- a/quadnames.c
+++ b/quadnames.c
@@ -1,5 +1,6 @@
 #include <u.h>
 #include <libc.h>
+#include <thread.h>
 #include <bio.h>
 
 #include "apl9.h"
@@ -16,6 +17,7 @@ Datum *getdiv(void);
 void setdiv(Datum);
 Datum *geta(void);
 Datum *getd(void);
+Datum *getself(void);
 
 Array *runfile(Array *);
 Array *quadthrow1(Array *);
@@ -23,9 +25,11 @@ Array *quadthrow2(Array *, Array *);
 Array *quadinfo(Array *);
 Array *quadproto(Array *);
 Array *quaducs(Array *);
+Array *quaddl(Array *);
 
 int needsnewline = 0;
 static Rune *quadquotebuf = nil;
+static Lock quadlock;
 
 QuadnameDef quadnames[] = {
 	{L"⍞", NameTag, getquotequad, setquotequad, nil, nil},
@@ -35,11 +39,13 @@ QuadnameDef quadnames[] = {
 	{L"⎕DIV", NameTag, getdiv, setdiv, nil, nil},
 	{L"⎕A", NameTag, geta, nil, nil, nil},
 	{L"⎕D", NameTag, getd, nil, nil, nil},
+	{L"⎕SELF", NameTag, getself, nil, nil, nil},
 	{L"⎕RUN", FunctionTag, nil, nil, runfile, nil},
 	{L"⎕THROW", FunctionTag, nil, nil, quadthrow1, quadthrow2},
 	{L"⎕INFO", FunctionTag, nil, nil, quadinfo, nil},
 	{L"⎕PROTO", FunctionTag, nil, nil, quadproto, nil},
 	{L"⎕UCS", FunctionTag, nil, nil, quaducs, nil},
+	{L"⎕DL", FunctionTag, nil, nil, quaddl, nil},
 	{nil, 0, nil, nil, nil, nil} /* MUST BE LAST */
 };
 
@@ -88,6 +94,7 @@ quadnamedatum(QuadnameDef q)
 Datum *
 getquotequad(void)
 {
+	lock(&quadlock);
 	int sizemax = 512;
 	int size;
 	Rune *input;
@@ -114,12 +121,14 @@ getquotequad(void)
 	result->tag = ArrayTag;
 	result->array = mkrunearray(input);
 	free(input);
+	unlock(&quadlock);
 	return result;
 }
 
 void
 setquotequad(Datum new)
 {
+	lock(&quadlock);
 	Rune *str = ppdatum(new);
 	if(needsnewline && quadquotebuf != nil){
 		if(quadquotebuf){
@@ -135,6 +144,7 @@ setquotequad(Datum new)
 	needsnewline = 1;
 	print("%S", str);
 	free(str);
+	unlock(&quadlock);
 }
 
 /* ⎕ */
@@ -150,8 +160,10 @@ getquad(void)
 void
 setquad(Datum new)
 {
+	lock(&quadlock);
 	needsnewline = 0;
 	print("%S\n", ppdatum(new));
+	unlock(&quadlock);
 }
 
 /* ⎕IO */
@@ -231,6 +243,17 @@ getd(void)
 	return d;
 }
 
+/* ⎕SELF */
+Datum *
+getself(void)
+{
+	Datum *d = mallocz(sizeof(Datum), 1);
+	d->tag = ArrayTag;
+	d->array = mkscalarint(threadid());
+	return d;
+}
+
+
 /* ⎕RUN */
 Array *
 runfile(Array *a)
@@ -337,4 +360,23 @@ quaducs(Array *a)
 	}else
 		throwerror(nil, EType);
 	return res;
+}
+
+/* ⎕DL */
+Array *
+quaddl(Array *a)
+{
+	/* TODO: return amount of seconds slept */
+	if(a->size != 1)
+		throwerror(nil, ELength);
+	if(a->type != AtypeInt && a->type != AtypeFloat)
+		throwerror(nil, EType);
+
+	if(a->type == AtypeInt && a->intdata[0] >= 0)
+		sleep(a->intdata[0] * 1000);
+	else if(a->type == AtypeFloat && a->floatdata[0] >= 0)
+		sleep(a->floatdata[0] * 1000);
+	else
+		throwerror(nil, EDomain);
+	return fnSame(a);
 }
\ No newline at end of file
diff --git a/symbol.c b/symbol.c
index ed6006d..4240ace 100644
--- a/symbol.c
+++ b/symbol.c
@@ -1,11 +1,11 @@
 #include <u.h>
 #include <libc.h>
+#include <thread.h>
 #include <bio.h>
 
 #include "apl9.h"
 
 Symtab *globalsymtab;
-DfnFrame *currentdfn;
 
 Symtab *newsymtab(void);
 void freesymtab(Symtab *);
@@ -20,7 +20,8 @@ void setsyntaxerr(Datum);
 Symbol *
 getsym(Rune *name, int fresh)
 {
-	DfnFrame *dfn = currentdfn;
+	ThreadData *td = getthreaddata();
+	DfnFrame *dfn = td->currentdfn;
 	Symtab *tab;
 	int done = 0;
 	do{
@@ -28,10 +29,10 @@ getsym(Rune *name, int fresh)
 			tab = dfn->symtab;
 		else
 			tab = globalsymtab;
-
-		for(int i = 0; i < tab->nsyms; i++)
+		for(int i = 0; i < tab->nsyms; i++){
 			if(runestrcmp(tab->syms[i]->name, name) == 0)
 				return tab->syms[i];
+		}
 		if(dfn)
 			dfn = dfn->prev;
 		else
@@ -39,8 +40,8 @@ getsym(Rune *name, int fresh)
 	}while(!done && !fresh);
 
 	/* make sure to allocate in the most local scope if the symbol is not found */
-	if(currentdfn)
-		tab = currentdfn->symtab;
+	if(td->currentdfn)
+		tab = td->currentdfn->symtab;
 
 	tab->nsyms++;
 	tab->syms = realloc(tab->syms, sizeof(Symbol *) * tab->nsyms);
@@ -106,12 +107,14 @@ initsymtab(void)
 DfnFrame *
 getcurrentdfn(void)
 {
-	return currentdfn;
+	ThreadData *td = getthreaddata();
+	return td->currentdfn;
 }
 
 DfnFrame *
 pushdfnframe(Rune *code, Datum *lefto, Datum *righto, Array *left, Array *right)
 {
+	ThreadData *td = getthreaddata();
 	DfnFrame *new = malloc(sizeof(DfnFrame));
 	new->code = code;
 	new->symtab = newsymtab();
@@ -124,27 +127,29 @@ pushdfnframe(Rune *code, Datum *lefto, Datum *righto, Array *left, Array *right)
 	}else
 		new->left = nil;
 	new->right = right;
-	new->prev = currentdfn;
-	currentdfn = new;
+	new->prev = td->currentdfn;
+	td->currentdfn = new;
 	return new;
 }
 
 void
 popdfnframe(void)
 {
-	if(currentdfn != nil){
-		DfnFrame *prev = currentdfn->prev;
-		freesymtab(currentdfn->symtab);
-		free(currentdfn);
-		currentdfn = prev;
+	ThreadData *td = getthreaddata();
+	if(td->currentdfn != nil){
+		DfnFrame *prev = td->currentdfn->prev;
+		freesymtab(td->currentdfn->symtab);
+		free(td->currentdfn);
+		td->currentdfn = prev;
 	}
 }
 
 vlong
 globalIO(void)
 {
-	if(currentdfn)
-		return currentdfn->symtab->io;
+	ThreadData *td = getthreaddata();
+	if(td->currentdfn)
+		return td->currentdfn->symtab->io;
 	else if(globalsymtab)
 		return globalsymtab->io;
 	else
@@ -154,8 +159,9 @@ globalIO(void)
 void
 globalIOset(vlong io)
 {
-	if(currentdfn)
-		currentdfn->symtab->io = io;
+	ThreadData *td = getthreaddata();
+	if(td->currentdfn)
+		td->currentdfn->symtab->io = io;
 	else
 		globalsymtab->io = io;
 }
@@ -163,8 +169,9 @@ globalIOset(vlong io)
 int
 globalDIV(void)
 {
-	if(currentdfn)
-		return currentdfn->symtab->div;
+	ThreadData *td = getthreaddata();
+	if(td->currentdfn)
+		return td->currentdfn->symtab->div;
 	else if(globalsymtab)
 		return globalsymtab->div;
 	else
@@ -174,8 +181,9 @@ globalDIV(void)
 void
 globalDIVset(int div)
 {
-	if(currentdfn)
-		currentdfn->symtab->div = div;
+	ThreadData *td = getthreaddata();
+	if(td->currentdfn)
+		td->currentdfn->symtab->div = div;
 	else
 		globalsymtab->div = div;
 }
@@ -192,7 +200,7 @@ getalpha(void)
 		res = malloc(sizeof(Datum));
 		*res = *dfn->left;
 		if(res->tag == ArrayTag)
-			incref(res->array);
+			incarrayref(res->array);
 		return res;
 	}
 	return res;
@@ -209,7 +217,7 @@ getomega(void)
 		res = mallocz(sizeof(Datum), 1);
 		res->tag = ArrayTag;
 		res->array = dfn->right;
-		incref(res->array);
+		incarrayref(res->array);
 	}
 	return res;
 }
@@ -225,7 +233,7 @@ getalphao(void)
 		res = malloc(sizeof(Datum));
 		*res = *dfn->lefto;
 		if(res->tag == ArrayTag)
-			incref(res->array);
+			incarrayref(res->array);
 	}
 	return res;
 }
@@ -241,7 +249,7 @@ getomegao(void)
 		res = malloc(sizeof(Datum));
 		*res = *dfn->righto;
 		if(res->tag == ArrayTag)
-			incref(res->array);
+			incarrayref(res->array);
 	}
 	return res;
 }