First try at implementing variables

1 files changed, 95 insertions, 33 deletions

diff --git a/eval.c b/eval.c
index 4f228a7..f6cdb0d 100644
--- a/eval.c
+++ b/eval.c
@@ -16,42 +16,62 @@ Datum monadfun(Datum, Datum);
 Datum dyadfun(Datum, Datum);
 Datum lpar(Datum, Datum);
 Datum rpar(Datum, Datum);
+Datum nameis(Datum, Datum);
+Datum assign(Datum, Datum);
+Datum *lookup(Datum);
 
-int bindingstrengths[12][12] = {
-/*	A  F  H  MO DO AF (  )  {  }  [  ] */
-	3, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* A */
-	1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* F */
-	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* H */
-	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* MO */
-	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* DO */
-	1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* AF */
-	4, 4, 4, 4, 4, 4, 0, 5, 4, 4, 4, 4, /* ( */
-	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* ) */
-	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* { */
-	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* } */
-	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* [ */
-	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* ] */
+int bindingstrengths[15][15] = {
+/*	A  F  H  MO DO AF (  )  {  }  [  ]  ←  IS N */
+	4, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* A */
+	2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* F */
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* H */
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* MO */
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* DO */
+	2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* AF */
+	5, 5, 5, 5, 5, 5, 0, 6, 5, 5, 5, 5, 5, 5, 5, /* ( */
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* ) */
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* { */
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* } */
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* [ */
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* ] */
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* ← */
+	1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* IS */
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 7, 0, 0, /* N */
 };
 
-evalfn evalfns[12][12] = {
-/*	A  F  H  MO DO AF (  )  {  }  [  ] */
-	strand, dyadfun, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* A */
-	monadfun, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* F */
-	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* H */
-	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* MO */
-	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* DO */
-	monadfun, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* AF */
-	lpar, lpar, lpar, lpar, lpar, 0, lpar, rpar, lpar, lpar, lpar, lpar, /* ( */
-	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* ) */
-	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* { */
-	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* } */
-	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* [ */
-	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* ] */
+evalfn evalfns[15][15] = {
+/*	A  F  H  MO DO AF (  )  {  }  [  ] ← IS N */
+	strand, dyadfun, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* A */
+	monadfun, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* F */
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* H */
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* MO */
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* DO */
+	monadfun, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* AF */
+	lpar, lpar, lpar, lpar, lpar, 0, lpar, rpar, lpar, lpar, lpar, lpar, lpar, lpar, lpar, /* ( */
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* ) */
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* { */
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* } */
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* [ */
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* ] */
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* ← */
+	assign, assign, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* IS */
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, nameis, 0, 0, /* N */	
 };
 
 Datum *
 eval(Datum *tokens, int *ntoks)
 {
+	errormsg = nil;
+
+	/* start by looking up first variable if needed */
+	if(*ntoks > 0 && tokens[(*ntoks)-1].tag == NameTag){
+		Datum *value = lookup(tokens[(*ntoks)-1]);
+		if(value == nil)
+			*ntoks = 0;
+		else
+			tokens[(*ntoks)-1] = *value;
+	}
+
 	while(*ntoks > 1){
 		int maxlevel = 0;
 		int offset;
@@ -59,6 +79,7 @@ eval(Datum *tokens, int *ntoks)
 		traceprint("CURRENT: %S\n", ppdatums(tokens, *ntoks));
 		for(offset = (*ntoks)-1; offset >= 0; offset--){
 			int level;
+retry:
 			if(offset == 0)
 				level = 0;
 			else{
@@ -66,11 +87,21 @@ eval(Datum *tokens, int *ntoks)
 				Datum right = tokens[offset];
 				level = bindingstrengths[left.tag][right.tag];
 			}
-			if(level < maxlevel){
+
+			if(level == 0 && tokens[offset-1].tag == NameTag){
+				Datum *value = lookup(tokens[offset-1]);
+				if(value == nil){
+					*ntoks = 0;
+					return tokens;
+				}else{
+					tokens[offset-1] = *value;
+					goto retry;
+				}
+			}else if(level < maxlevel){
 				Datum left = tokens[offset];
 				Datum right = tokens[offset+1];
 				fn = evalfns[left.tag][right.tag];
-				traceprint("Reducing %S and %S\n", ppdatum(left), ppdatum(right));
+				traceprint("Reducing %S and %S (fn=%p, level=%d, max=%d)\n", ppdatum(left), ppdatum(right), fn, level, maxlevel);
 				break;
 			}else if(level > maxlevel)
 				maxlevel = level;
@@ -88,10 +119,21 @@ eval(Datum *tokens, int *ntoks)
 	return tokens;
 }
 
+Datum *
+lookup(Datum var)
+{
+	traceprint("VAR LOOKUP %S\n", var.symbol->name);
+	if(var.symbol->undefined){
+		errormsg = runesmprint("Variable undefined: %S\n", var.symbol->name);
+		return nil;
+	}else
+		return &var.symbol->value;
+}
+
 Datum
 strand(Datum left, Datum right)
 {
-	traceprint("Stranding\n");
+	traceprint("Stranding (%d %d)\n", left.array->stranded, right.array->stranded);
 	Datum result;
 	Array *leftarr = left.array->stranded ? left.array : fnEnclose(left.array);
 	Array *rightarr = right.array->stranded ? right.array : fnEnclose(right.array);
@@ -110,9 +152,9 @@ monadfun(Datum left, Datum right)
 
 	/* TODO handle undefined functions here */
 	if(left.func.left)
-		result.array = dyadfunctiondefs[left.code](left.func.left, right.array);
+		result.array = dyadfunctiondefs[left.func.code](left.func.left, right.array);
 	else
-		result.array = monadfunctiondefs[left.code](right.array);
+		result.array = monadfunctiondefs[left.func.code](right.array);
 	return result;
 }
 
@@ -147,4 +189,24 @@ rpar(Datum left, Datum right)
 	Datum *result = eval(left.expr.toks, &left.expr.ntoks);
 	result[0].array->stranded = 0;
 	return result[0]; /* TODO handle error if ntoks != 1 */
+}
+
+Datum
+nameis(Datum left, Datum right)
+{
+	traceprint("NAME SYMBOL %p\n", left.symbol);
+	traceprint("NAMEIS %S←\n", left.symbol->name);
+	right.tag = AssignmentTag;
+	right.symbol = left.symbol;
+	return right;
+}
+
+Datum
+assign(Datum left, Datum right)
+{
+	left.symbol->value = right; /* TODO think about this*/
+	left.symbol->undefined = 0;
+	if(left.symbol->value.tag == ArrayTag)
+		left.symbol->value.array->stranded = 0;
+	return right;
 }
\ No newline at end of file