Implement lexical scope instead of dynamic scope rules.

4 files changed, 11 insertions, 5 deletions

diff --git a/apl9.h b/apl9.h
index bbba10f..2cf0069 100644
--- a/apl9.h
+++ b/apl9.h
@@ -153,6 +153,7 @@ struct Function
 		QuadnameDef *quad;
 		FunctionTrain train;
 	};
+	DfnFrame *scope;
 	Array *left;
 };
 
@@ -219,7 +220,8 @@ struct DfnFrame
 	Array *right;
 	Datum *lefto;
 	Datum *righto;
-	DfnFrame *prev;
+	DfnFrame *prev; /* prev in the call stack */
+	DfnFrame *chain; /* prev in the lexical scope */
 };
 
 struct ThreadData
@@ -279,7 +281,7 @@ Datum *eval(Statement *, int);
 Symbol *getsym(Rune *, int);
 void initsymtab(void);
 DfnFrame *getcurrentdfn(void);
-DfnFrame *pushdfnframe(Rune *, Datum *, Datum *, Array *, Array *);
+DfnFrame *pushdfnframe(Rune *, DfnFrame *, Datum *, Datum *, Array *, Array *);
 void popdfnframe(void);
 vlong globalIO(void);
 void globalIOset(vlong);
diff --git a/functions.c b/functions.c
index 46cbe7a..7e462c3 100644
--- a/functions.c
+++ b/functions.c
@@ -141,7 +141,7 @@ runfunc(Function f, Array *left, Array *right)
 			code = f.operator.dop;
 		}
 
-		pushdfnframe(code, lefto, righto, left, right);
+		pushdfnframe(code, f.scope, lefto, righto, left, right);
 		Datum *dfnres = evalline(code, nil, 0);
 		popdfnframe();
 
@@ -228,6 +228,7 @@ rundfn(Rune *code, Datum *lefto, Datum *righto, Array *left, Array *right)
 		Function dfn;
 		dfn.type = FunctypeDfn;
 		dfn.dfn = code;
+		dfn.scope = getcurrentdfn();
 		return runfunc(dfn, left, right);
 	}else if(lefto != nil){
 		Function dop;
@@ -237,6 +238,7 @@ rundfn(Rune *code, Datum *lefto, Datum *righto, Array *left, Array *right)
 		dop.operator.right = righto;
 		dop.operator.dyadic = righto != nil;
 		dop.operator.dop = code;
+		dop.scope = getcurrentdfn();
 		return runfunc(dop, left, right);
 	}else{
 		throwerror(L"Malformed call to rundfn", ENotImplemented);
diff --git a/lexer.c b/lexer.c
index ed2c2e4..93fdb62 100644
--- a/lexer.c
+++ b/lexer.c
@@ -118,6 +118,7 @@ lexline(InputStream *input, int toplevel)
 				stmt->toks[stmt->ntoks] = allocdatum(FunctionTag, 0);
 				stmt->toks[stmt->ntoks]->func.type = FunctypeDfn;
 				stmt->toks[stmt->ntoks]->func.dfn = runestrdup(buf);
+				stmt->toks[stmt->ntoks]->func.scope = getcurrentdfn();
 			}else{
 				stmt->toks[stmt->ntoks] = allocdatum(oplevel == 1 ? MonadicOpTag : DyadicOpTag, 0);
 				stmt->toks[stmt->ntoks]->operator.type = OperatortypeDop;
diff --git a/symbol.c b/symbol.c
index 8f4797a..6e9aa4a 100644
--- a/symbol.c
+++ b/symbol.c
@@ -34,7 +34,7 @@ getsym(Rune *name, int fresh)
 				return tab->syms[i];
 		}
 		if(dfn)
-			dfn = dfn->prev;
+			dfn = dfn->chain;
 		else
 			done = 1;
 	}while(!done && !fresh);
@@ -108,7 +108,7 @@ getcurrentdfn(void)
 }
 
 DfnFrame *
-pushdfnframe(Rune *code, Datum *lefto, Datum *righto, Array *left, Array *right)
+pushdfnframe(Rune *code, DfnFrame *scope, Datum *lefto, Datum *righto, Array *left, Array *right)
 {
 	ThreadData *td = getthreaddata();
 	DfnFrame *new = emalloc(sizeof(DfnFrame));
@@ -129,6 +129,7 @@ pushdfnframe(Rune *code, Datum *lefto, Datum *righto, Array *left, Array *right)
 	new->right = right;
 	incarrayref(right);
 	new->prev = td->currentdfn;
+	new->chain = scope;
 	td->currentdfn = new;
 	return new;
 }