refactor error checking and argument parsing

1 files changed, 29 insertions, 30 deletions

diff --git a/com.c b/com.c
index 5a98ef1..72975ed 100644
--- a/com.c
+++ b/com.c
@@ -7,6 +7,7 @@
 #include "chunk.h"
 #include "ast.h"
 #include "read.h"
+#include "util.h"
 
 #define BYTECODE(C) (C->ch->bc)
 
@@ -86,10 +87,7 @@ void single_form(Compiler *C, AstVec l, Op op) {
 
 void set_form(Compiler *C, AstVec l, Op _) {
 	AstNode ident = l.vals[1];
-	if (ident.ty != AST_IDENT) {
-		fprintf(stderr, "set's first argument must be identifier");
-		exit(1);
-	}
+	CHECK(ident.ty == AST_IDENT, "set's first argument must be identifier");
 	ObjString *o = objstring_copy_cstr(C->S, ident.as.str);
 	compile_node(C, l.vals[2]);
 	chunk_wbc(C, OP_SETGLOBAL);
@@ -160,13 +158,12 @@ void arith_form(Compiler *C, AstVec l, Op op) {
 
 void fn_form(Compiler *C, AstVec l, Op op) {
 	// (fn (arg arg arg) body ...)
-	if (l.vals[1].ty != AST_LIST) {
-		fprintf(stderr, "fn's first argument must be list");
-		exit(1);
-	}
+	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);
+	ObjFunc *func = objfunc_new(C->S, arity);
 	Compiler subcompiler = compiler_new(C, &func->ch);
 
 	for (int i = 2; i < l.len - 1; i++) {
@@ -246,9 +243,7 @@ static void compile_node(Compiler *C, AstNode a) {
 	case AST_LIST: {
 		AstVec l = a.as.list;
 
-		#define CK(cond, msg) if (!(cond)) { fputs(msg "\n", stderr); exit(1); }
-		CK(l.len > 0, "can't handle empty list");
-		#undef CK
+		CHECK(l.len > 0, "can't handle empty list");
 
 		BuiltinForm *form = NULL;
 
@@ -263,15 +258,13 @@ static void compile_node(Compiler *C, AstNode a) {
 		}
 
 		if (form != NULL) {
-			if (form->ellipsis && l.len < form->min_params + 1) {
-				fprintf(stderr, "%s requires at least %d parameters\n",
+			size_t nparams = l.len - 1;
+			if (form->ellipsis) 
+				CHECK(nparams >= form->min_params, "%s requires at least %d parameters",
 					form->name, form->min_params);
-				exit(1);
-			} else if (!form->ellipsis && l.len != form->min_params + 1) {
-				fprintf(stderr, "%s requires exactly %d parameters\n",
+			else 
+				CHECK(nparams == form->min_params, "%s requires exactly %d parameters",
 					form->name, form->min_params);
-				exit(1);
-			}
 
 			form->action(C, l, form->op);
 		} else {
@@ -298,19 +291,23 @@ int main(int argc, char **argv) {
 	State *S = &st;
 	Chunk ch = chunk_new(S);
 
-	S->do_disasm = (argc > 1 && 0 == strcmp(argv[1], "-l"));
+	S->do_disasm = false;
 	S->do_trace = false;
 
-	char n1[] = "foo";
-	char n2[] = "bar";
-	char n3[] = "baz";
-	ObjString *o1 = objstring_copy_cstr(S, n1);
-	ObjString *o2 = objstring_copy_cstr(S, n2);
-	ObjString *o3 = objstring_copy_cstr(S, n3);
-
-	ht_put(S, &st.globals, o1, VAL_NUM(69)); 
-	ht_put(S, &st.globals, o2, VAL_NUM(2)); 
-	ht_put(S, &st.globals, o3, VAL_NUM(3)); 
+	for (int i = 1; i < argc; i++) {
+		if (argv[i][0] != '-') break;
+		switch (argv[i][1]) {
+		case 'D': 
+			CHECK(strlen(argv[i]) > 1, "unknown option a");
+			switch (argv[i][2]) {
+				case 'l': S->do_disasm = true; break;
+				case 't': S->do_trace = true; break;
+				default: ERROR("unknown option b");
+			}
+		break;
+		default: ERROR("unknown option c");
+		}
+	}
 
 	AstNode an = read();
 
@@ -331,3 +328,5 @@ int main(int argc, char **argv) {
 
 	return runvm(S);
 }
+#undef CHECK
+#undef ER