get functions and arguments and returning to work fully

1 files changed, 40 insertions, 25 deletions

diff --git a/com.c b/com.c
index b2f1f09..c5362cd 100644
--- a/com.c
+++ b/com.c
@@ -21,6 +21,7 @@ Compiler compiler_new(Compiler *outer, Chunk *ch) {
 		.S = outer->S,
 		.ch = ch,
 		.stack_cur = 0,
+		.scope = NULL,
 	};
 }
 
@@ -211,26 +212,6 @@ void arith_form(Compiler *C, AstVec l, Op op) {
 	compile_opcode(C, op);
 }
 
-void fn_form(Compiler *C, AstVec l, Op _) {
-	// (fn (arg arg arg) body ...)
-	CHECK(l.vals[1].ty == AST_LIST, "fn's first argument must be list");
-	AstVec arglist = l.vals[1].as.list;
-	CHECK(arglist.len <= 255, "maximum 255 args for function");
-	uint8_t arity = arglist.len;
-
-	ObjFunc *func = objfunc_new(C->S, arity);
-	Compiler subcompiler = compiler_new(C, &func->ch);
-
-	for (int i = 2; i < l.len - 1; i++) {
-		compile_node(&subcompiler, l.vals[i]);
-		compile_opcode(&subcompiler, OP_DROP);
-	}
-	compile_node(&subcompiler, l.vals[l.len-1]);
-	compile_opcode(&subcompiler, OP_RET);
-
-	compile_opcode(C, OP_LOADK);
-	compile_byte(C, compile_constant(C, VAL_OBJ(func)));
-}
 
 static void begin_scope(Compiler *C) {
 	Scope *sc = malloc(sizeof(Scope));
@@ -261,6 +242,7 @@ static void declare_local(Compiler *C, char *name) {
 	// -1 because local is expected to be already on the stack
 	// ie sitting just below where stack_cur points
 	l->slot = C->stack_cur - 1;
+	// printf("declaring local %s at %d, stack_cur is %d\n",l->name, l->slot, C->stack_cur);
 }
 
 void let_form(Compiler *C, AstVec l, Op _) {
@@ -286,7 +268,41 @@ void let_form(Compiler *C, AstVec l, Op _) {
 	end_scope(C);
 }
 
+void fn_form(Compiler *C, AstVec l, Op _) {
+	// (fn (arg arg arg) body ...)
+	CHECK(l.vals[1].ty == AST_LIST, "fn's first argument must be list");
+	AstVec arglist = l.vals[1].as.list;
+	CHECK(arglist.len <= 255, "maximum 255 args for function");
+	uint8_t arity = arglist.len;
+
+	ObjFunc *func = objfunc_new(C->S, arity);
+	Compiler subcompiler = compiler_new(C, &func->ch);
 
+	Compiler *SC = &subcompiler;
+	begin_scope(SC);
+	// when called, stack slot 0 contains the function itself,
+	// stack slots 1..n contain passed arguments
+	SC->stack_cur ++;
+	declare_local(SC, "__func__");
+	for (int i = 0; i < arity; i++) {
+		AstNode argname = arglist.vals[i];
+		CHECK(argname.ty == AST_IDENT, "argument name must be identifier");
+		SC->stack_cur ++;
+		declare_local(SC, argname.as.str);
+	}
+
+	for (int i = 2; i < l.len - 1; i++) {
+		compile_node(SC, l.vals[i]);
+		compile_opcode(SC, OP_DROP);
+	}
+	compile_node(&subcompiler, l.vals[l.len-1]);
+
+	end_scope(SC);
+	compile_opcode(SC, OP_RET);
+
+	compile_opcode(C, OP_LOADK);
+	compile_byte(C, compile_constant(C, VAL_OBJ(func)));
+}
 
 typedef struct {
 	char *name;
@@ -444,14 +460,13 @@ int main(int argc, char **argv) {
 
 	AstNode an = read();
 
-	Compiler com = (Compiler){
-		.S = S,
-		.ch = &ch,
-	};
+	Compiler com = (Compiler){ 0 };
+	com.S = S;
+	com.ch = &ch;
+
 	Compiler *C = &com;
 	compile_node(C, an);
 
-
 	compile_opcode(C, OP_PUTS);
 	compile_opcode(C, OP_HALT);