refactor error checking and argument parsing

5 files changed, 45 insertions, 34 deletions

diff --git a/Makefile b/Makefile
index 58ef051..fcb0c82 100644
--- a/Makefile
+++ b/Makefile
@@ -1,5 +1,5 @@
-CS=ast.c         com.c dis.c ht.c mem.c prs.c read.c state.c val.c vm.c
-HS=ast.h chunk.h com.h dis.h ht.h mem.h prs.h read.h state.h val.h vm.h
+CS=ast.c         com.c dis.c ht.c mem.c prs.c read.c state.c        val.c vm.c
+HS=ast.h chunk.h com.h dis.h ht.h mem.h prs.h read.h state.h util.h val.h vm.h
 CFLAGS=$(EXTRA_CFLAGS) -O3 -lm -Wall -Wpedantic -Werror=implicit-function-declaration
 
 bth: $(CS) $(HS) Makefile
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
diff --git a/util.h b/util.h
new file mode 100644
index 0000000..b0f2658
--- /dev/null
+++ b/util.h
@@ -0,0 +1,10 @@
+#ifndef _util_h
+#define _util_h
+
+#define CHECK(cond, ...) do { if (!(cond)) { fprintf(stderr, __VA_ARGS__); exit(1); } } while(0)
+#define ERROR(...) CHECK(false, __VA_ARGS__)
+
+
+
+#endif
+
diff --git a/val.c b/val.c
index 930ebd8..ec200d3 100644
--- a/val.c
+++ b/val.c
@@ -47,9 +47,10 @@ static ObjString *objstring_create(State *S, char *src, size_t len, uint32_t has
 	return o;
 }
 
-ObjFunc *objfunc_new(State *S) {
+ObjFunc *objfunc_new(State *S, uint8_t arity) {
 	ObjFunc *o = NEW_OBJ(S, ObjFunc, OTY_FUNC);
 	o->ch = chunk_new(S);
+	o->arity = arity;
 	return o;
 }
 
diff --git a/val.h b/val.h
index 6aa85c5..4ee76d2 100644
--- a/val.h
+++ b/val.h
@@ -54,6 +54,7 @@ typedef struct {
 typedef struct {
 	Obj obj;
 	Chunk ch;
+	uint8_t arity;
 } ObjFunc;
 
 // Constructs a new objstring from the given C string,
@@ -64,7 +65,7 @@ ObjString *objstring_copy_cstr(State *s, char *str);
 // taking ownership of the provided data.
 ObjString *objstring_take(State *S, char *src, size_t len);
 
-ObjFunc *objfunc_new(State *S);
+ObjFunc *objfunc_new(State *S, uint8_t arity);
 
 #define IS_NIL(x) (x.ty == TY_NIL)
 #define IS_NUM(x) (x.ty == TY_NUM)