Rework symbol lookup to use lexical scoping, and implement recursive function call via ∇

1 files changed, 37 insertions, 13 deletions

diff --git a/functions.c b/functions.c
index bc4d96c..c8bff78 100644
--- a/functions.c
+++ b/functions.c
@@ -4,7 +4,7 @@
 
 #include "apl9.h"
 
-Rune primfuncnames[] = L"+-×÷*⍟⌹○!?|⌈⌊⊥⊤⊣⊢=≠≤<>≥≡≢∨∧⍲⍱↑↓⊂⊃⊆⌷⍋⍒⍳⍸∊⍷∪∩~,⍪⍴⌽⊖⍉⍎⍕";
+Rune primfuncnames[] = L"+-×÷*⍟⌹○!?|⌈⌊⊥⊤⊣⊢=≠≤<>≥≡≢∨∧⍲⍱↑↓⊂⊃⊆⌷⍋⍒⍳⍸∊⍷∪∩~,⍪⍴⌽⊖⍉⍎⍕∇";
 
 fnmonad monadfunctiondefs[] = {
 	fnSame, /* + */
@@ -59,6 +59,7 @@ fnmonad monadfunctiondefs[] = {
 	fnTranspose, /* ⍉ */
 	0, /* ⍎ */
 	0, /* ⍕ */
+	fnSelfRef1, /* ∇ */
 };
 
 fndyad dyadfunctiondefs[] = {
@@ -114,8 +115,11 @@ fndyad dyadfunctiondefs[] = {
 	0, /* ⍉ */
 	0, /* ⍎ */
 	0, /* ⍕ */
+	fnSelfRef2, /* ∇ */
 };
 
+DfnFrame *currentdfn; /* a stack of active dnf calls */
+
 vlong gcd_int(vlong, vlong);
 double gcd_float(double, double);
 
@@ -125,26 +129,23 @@ runfunc(Function f, Array *left, Array *right)
 {
 	Array *result;
 	if(f.type == FunctypeDfn){
-		Symtab *tmpsymtab = currentsymtab;
-		currentsymtab = newsymtab();
-
+		pushdfnframe(f.dfn);
 		if(left){
-			Symbol *alpha = getsym(currentsymtab, L"⍺");
+			Symbol *alpha = getsym(L"⍺");
 			alpha->value.tag = ArrayTag;
 			alpha->value.array = left;
 			alpha->undefined = 0;
 			incref(left);
 		}
 
-		Symbol *omega = getsym(currentsymtab, L"⍵");
+		Symbol *omega = getsym(L"⍵");
 		omega->value.tag = ArrayTag;
 		omega->value.array = right;
 		omega->undefined = 0;
 		incref(right);
 
 		Datum *dfnres = evalline(f.dfn, 0);
-		freesymtab(currentsymtab);
-		currentsymtab = tmpsymtab;
+		popdfnframe();
 		result = (*dfnres).array; /* TODO what if the evaluation failed */
 	}else if(f.type == FunctypePrim){
 		if(left){
@@ -496,12 +497,13 @@ fnGradeUp(Array *right)
 	int i,j;
 	int len = right->shape[0];
 	Array **elems = malloc(sizeof(Array *) * len);
-	Array *index = mkscalarint(currentsymtab->io);
+	Array *index = mkscalarint(globalIO());
 	Array *order = allocarray(AtypeInt, 1, len);
 	order->shape[0] = len;
 
+	vlong io = globalIO();
 	for(i = 0; i < len; i++, index->intdata[0]++){
-		order->intdata[i] = currentsymtab->io + i;
+		order->intdata[i] = io + i;
 		elems[i] = fnIndex(index, right);
 	}
 
@@ -541,7 +543,7 @@ fnIndexGenerator(Array *right)
 	vlong n = right->intdata[0];
 	Array *res = allocarray(AtypeInt, 1, n);
 	res->shape[0] = n;
-	vlong io = currentsymtab->io;
+	vlong io = globalIO();
 	for(vlong i = 0; i < n; i++)
 		res->intdata[i] = i + io;
 	return res;
@@ -692,6 +694,17 @@ fnTranspose(Array *right)
 	return res;
 }
 
+Array *
+fnSelfRef1(Array *right)
+{
+	if(currentdfn != nil)
+		return rundfn(currentdfn->code, nil, right);
+	else{
+		throwerror(nil, ESyntax);
+		return nil;
+	}
+}
+
 /* Dyadic functions */
 
 /* macro to define dyadic scalar functions */
@@ -747,7 +760,7 @@ SCALAR_FUNCTION_2(fnTimes, 0, left->type,
 SCALAR_FUNCTION_2(fnDivide, 1, left->type,
 	case AtypeFloat:
 		if(right->floatdata[i] == 0){
-			if(currentsymtab->div)
+			if(globalDIV())
 				res->floatdata[i] = 0;
 			else
 				throwerror(nil, EDomain);
@@ -994,7 +1007,7 @@ fnTake(Array *left, Array *right)
 Array *
 fnIndex(Array *left, Array *right)
 {
-	int io = currentsymtab->io;
+	int io = globalIO();
 	int i;
 
 	if(left->rank > 1)
@@ -1221,6 +1234,17 @@ fnReshape(Array *left, Array *right)
 	return res;
 }
 
+Array *
+fnSelfRef2(Array *left, Array *right)
+{
+	if(currentdfn != nil)
+		return rundfn(currentdfn->code, left, right);
+	else{
+		throwerror(nil, ESyntax);
+		return nil;
+	}
+}
+
 /* helper functions */
 vlong
 gcd_int(vlong a, vlong b)