Add strand assignment (a (b c) d)←1 (2 3) 4

1 files changed, 81 insertions, 20 deletions

diff --git a/eval.c b/eval.c
index e33c3b5..8829609 100644
--- a/eval.c
+++ b/eval.c
@@ -15,6 +15,7 @@ Datum monadfun(Datum, Datum);
 Datum dyadfun(Datum, Datum);
 Datum parens(Datum, Datum);
 Datum nameis(Datum, Datum);
+Datum namesis(Datum, Datum);
 Datum assign(Datum, Datum);
 Datum monadop(Datum, Datum);
 Datum dyadop(Datum, Datum);
@@ -29,8 +30,8 @@ int bindingstrengths[11][11] = {
 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* MO */
 	6, 6, 6, 0, 0, 0, 0, 0, 0, 0, 0, /* DO */
 	3, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* AF */
-	0, 0, 0, 0, 0, 0, 0, 8, 0, 0, 0, /* ( */
-	8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, /* ) */
+	0, 0, 0, 0, 0, 0, 0, 8, 9, 0, 0, /* ( */
+	0, 0, 0, 0, 0, 0, 0, 0, 9, 0, 0, /* ) */
 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* ← */
 	1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, /* IS */
 	0, 0, 0, 0, 0, 0, 0, 0, 9, 0, 0, /* N */
@@ -44,10 +45,10 @@ evalfn evalfns[11][11] = {
 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* MO */
 	dyadop, dyadop, dyadop, 0, 0, 0, 0, 0, 0, 0, 0, /* DO */
 	monadfun, train, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* AF */
-	0, 0, 0, 0, 0, 0, 0, parens, 0, 0, 0, /* ( */
-	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* ) */
+	0, 0, 0, 0, 0, 0, 0, parens, namesis, 0, 0, /* ( */
+	0, 0, 0, 0, 0, 0, 0, 0, namesis, 0, 0, /* ) */
 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* ← */
-	assign, assign, assign, assign, assign, 0, 0, 0, 0, 0, 0, /* IS */
+	assign, assign, assign, assign, assign, 0, assign, 0, 0, 0, 0, /* IS */	
 	0, 0, 0, 0, 0, 0, 0, 0, nameis, 0, 0, /* N */	
 };
 
@@ -221,27 +222,87 @@ nameis(Datum left, Datum right)
 {
 	traceprint("NAMEIS %S←\n", left.name);
 	right.tag = AssignmentTag;
-	right.name = left.name;
+	right.names.ntoks = 1;
+	right.names.toks = malloc(sizeof(Datum));
+	right.names.toks[0] = left;
+	return right;
+}
+
+Datum
+namesis(Datum left, Datum right)
+{
+	if(left.tag == RParTag)
+		return right;
+
+	traceprint("NAMES IS %S %S\n", ppdatum(left), ppdatum(right));
+	right.tag = AssignmentTag;
+	right.names = left.stmt;
 	return right;
 }
 
 Datum
 assign(Datum left, Datum right)
 {
-	Symbol *symbol = getsym(left.name, 0);
-	if(symbol->setfn != nil)
-		symbol->setfn(right);
-	else{
-		/* re-assign the symbol to one that is sure to be local. This enables shadowing */
-		symbol = getsym(left.name, 1);
-
-		if(symbol->undefined == 0 && symbol->value.tag == ArrayTag)
-			freearray(symbol->value.array);
-		symbol->value = right;
-		symbol->undefined = 0;
-		if(symbol->value.tag == ArrayTag){
-			symbol->value.array->stranded = 0;
-			incref(right.array); /* for the binding */
+	traceprint("ASSIGN %S %S\n", ppdatum(left), ppdatum(right));
+	if(left.names.ntoks == 1){
+		if(left.names.toks[0].tag != NameTag)
+			throwerror(nil, ESyntax);
+
+		Symbol *symbol = getsym(left.names.toks[0].name, 0);
+		if(symbol->setfn != nil)
+			symbol->setfn(right);
+		else{
+			/* re-assign the symbol to one that is sure to be local. This enables shadowing */
+			symbol = getsym(symbol->name, 1);
+
+			if(symbol->undefined == 0 && symbol->value.tag == ArrayTag)
+				freearray(symbol->value.array);
+			symbol->value = right;
+			symbol->undefined = 0;
+			if(symbol->value.tag == ArrayTag){
+				symbol->value.array->stranded = 0;
+				incref(right.array); /* for the binding */
+			}
+		}
+	}else{
+		if(right.tag != ArrayTag)
+			throwerror(nil, ESyntax);
+		if(right.array->rank != 1 && right.array->rank != 0)
+			throwerror(nil, ERank);
+
+		int nlocs = 0;
+		Datum *locations = nil;
+		for(int i = 0; i < left.names.ntoks; i++){
+			Datum loc = left.names.toks[i];
+			if(loc.tag == NameTag){
+				nlocs++;
+				locations = realloc(locations, sizeof(Datum) * nlocs);
+				locations[nlocs-1].tag = AssignmentTag;
+				locations[nlocs-1].names.ntoks = 1;
+				locations[nlocs-1].names.toks = malloc(sizeof(Datum));
+				locations[nlocs-1].names.toks[0] = loc;
+			}else if(loc.tag == LParTag){
+				i++;
+				nlocs++;
+				locations = realloc(locations, sizeof(Datum) * nlocs);
+				locations[nlocs-1].tag = AssignmentTag;
+				locations[nlocs-1].names = loc.stmt;
+			}
+		}
+
+		if(right.array->rank == 1 && right.array->size != nlocs)
+			throwerror(nil, ELength);
+
+		for(int i = 0; i < nlocs; i++){
+			if(right.array->rank == 0)
+				assign(locations[i], right);
+			else{
+				Datum item;
+				item.tag = ArrayTag;
+				item.array = arrayitem(right.array, i);
+				assign(locations[i], item);
+				freearray(item.array);
+			}
 		}
 	}
 	right.shy = 1;