started cgen

3 files changed, 864 insertions, 0 deletions

diff --git a/archive/base_cgen.c b/archive/base_cgen.c
new file mode 100644
index 0000000..d773ba9
--- /dev/null
+++ b/archive/base_cgen.c
@@ -0,0 +1,295 @@
+/* figures out types and writes function prototypes */
+/* TODO: check ferror */
+typedef enum {
+	  CGEN_WRITING_TO_H,
+	  CGEN_WRITING_TO_C
+} CGenWritingTo;
+typedef struct {
+	FILE *c_out;
+	FILE *h_out;
+	unsigned long anon_fn_count;
+	unsigned long anon_var_count;
+	Block *block;
+	int indent_level;
+	bool indent_next; /* should the next thing written be indented? */
+	CGenWritingTo writing_to;
+	Identifier main_ident;
+} CGenerator;
+
+static FILE *cgen_writing_to(CGenerator *g) {
+	switch (g->writing_to) {
+	case CGEN_WRITING_TO_H:
+		return g->h_out;
+	case CGEN_WRITING_TO_C:
+		return g->c_out;
+	}
+	assert(0);
+	return NULL;
+}
+
+static void cgen_indent(CGenerator *g) {
+	if (g->indent_next) {
+		for (int i = 0; i < g->indent_level; i++)
+			fprintf(cgen_writing_to(g), "\t");
+		g->indent_next = false;
+	}
+}
+
+static void cgen_vwrite(CGenerator *g, const char *fmt, va_list args) {
+	cgen_indent(g);
+	vfprintf(cgen_writing_to(g), fmt, args);
+}
+
+static void cgen_write(CGenerator *g, const char *fmt, ...) {
+	va_list args;
+	va_start(args, fmt);
+	cgen_vwrite(g, fmt, args);
+	va_end(args);
+}
+
+/* Used to write an UNNECESSARY space */
+static void cgen_space(CGenerator *g) {
+	cgen_write(g, " ");
+}
+
+/* Used to write something followed by an UNNECESSARY newline */
+static void cgen_writeln(CGenerator *g, const char *fmt, ...) {
+	va_list args;
+	va_start(args, fmt);
+	cgen_vwrite(g, fmt, args);
+	va_end(args);
+	cgen_write(g, "\n");
+	g->indent_next = true;
+}
+	
+/* static void cgen_write_comment(CGenerator *g, const char *fmt, ...) { */
+/* 	cgen_write(g, "/\* "); */
+/* 	va_list args; */
+/* 	va_start(args, fmt); */
+/* 	cgen_vwrite(g, fmt, args); */
+/* 	va_end(args); */
+/* 	cgen_write(g, " *\/"); */
+/* } */
+
+static void cgen_write_line_comment(CGenerator *g, const char *fmt, ...) {
+	/* could switch to // for c99 */
+	cgen_write(g, "/* ");
+	va_list args;
+	va_start(args, fmt);
+	cgen_vwrite(g, fmt, args);
+	va_end(args);
+	cgen_write(g, " */\n");
+}
+
+
+/* Pass NULL for where if you don't want to check if it's declared */
+static bool cgen_fn_name(CGenerator *g, FnExpr *f, Location *where);
+static bool cgen_ident(CGenerator *g, Identifier i, Location *where) {
+	if (where) {
+		IdentDecl *id_decl = ident_decl(i);
+		if (!id_decl) {
+			err_print(*where, "Identifier undeclared: %s", ident_to_str(i));
+			return false;
+		}
+		Declaration *decl = id_decl->decl;
+		if ((decl->flags & DECL_FLAG_HAS_EXPR) && (decl->flags & DECL_FLAG_CONST)) {
+			if (decl->expr.kind == EXPR_FN) {
+				cgen_fn_name(g, decl->expr.fn, NULL);
+				return true;
+			}
+		}
+	}
+	cgen_indent(g);
+	fprint_ident_reduced_charset(cgen_writing_to(g), i);
+	return true;
+}
+
+static const char *builtin_type_to_str(BuiltinType b) {
+	/* TODO: make this return int/long/etc. if stdint.h is not available */
+	switch (b) {
+	case BUILTIN_I8: return "int8_t";
+	case BUILTIN_I16: return "int16_t";
+	case BUILTIN_I32: return "int32_t";
+	case BUILTIN_I64: return "int64_t";
+	case BUILTIN_U8: return "uint8_t";
+	case BUILTIN_U16: return "uint16_t";
+	case BUILTIN_U32: return "uint32_t";
+	case BUILTIN_U64: return "uint64_t";
+	case BUILTIN_FLOAT: return "float";
+	case BUILTIN_DOUBLE: return "double";
+	case BUILTIN_TYPE_COUNT: break;
+	}
+	assert(0);
+	return NULL;
+}
+
+/* will this function use a pointer parameter for output? (e.g. fn()[3]int => void(int (*x)[3]) */
+static bool cgen_fn_uses_out_param(Type *fn_ret_type) {
+	switch (fn_ret_type->kind) {
+	case TYPE_TUPLE:
+	case TYPE_ARR:
+		return true;
+	default:
+		return false;
+	}
+}
+
+
+static void cgen_anon_var(CGenerator *g, unsigned long v) {
+	cgen_write(g, "av___%lu", v);
+}
+
+static void cgen_anon_fn(CGenerator *g, unsigned long f) {
+	cgen_write(g, "af___%lu", f);
+}
+
+static void cgen_type_pre(CGenerator *g, Type *t) {
+	switch (t->kind) {
+	case TYPE_VOID:
+		cgen_write(g, "void ");
+		break;
+	case TYPE_BUILTIN:
+		cgen_write(g, "%s ", builtin_type_to_str(t->builtin));
+		break;
+	case TYPE_FN: {
+		Type *types = t->fn.types.data;
+		Type *ret_type = &types[0];
+		if (cgen_fn_uses_out_param(ret_type)) {
+			cgen_write(g, "void ");
+		} else {
+			cgen_type_pre(g, ret_type);
+		}
+		cgen_write(g, "(*");
+	} break;
+	case TYPE_TUPLE:
+		assert(0);
+		return;
+	case TYPE_UNKNOWN:
+		err_print(t->where, "Type of unknown-typed expression required (x := #C(\"...\") will not work; you need to annotate the type of x).");
+	    abort();
+	case TYPE_ARR:
+		cgen_type_pre(g, t->arr.of);
+		break;
+	}
+}
+
+static void cgen_type_post(CGenerator *g, Type *t);
+/* either pass NULL for param_types (x)or for params */
+static void cgen_fn_params(CGenerator *g, Type *param_types, Param *params, size_t nparams, Type *ret_type) {
+	bool uses_out_param = cgen_fn_uses_out_param(ret_type);
+	   
+	cgen_write(g, "(");
+	if (nparams) {
+		for (size_t i = 0; i < nparams; i++) {
+			if (i) {
+				cgen_write(g, ",");
+				cgen_space(g);
+			}
+			if (param_types) {
+				cgen_type_pre(g, &param_types[i]);
+				cgen_type_post(g, &param_types[i]);
+			} else {
+				Param *p = &params[i];
+				cgen_type_pre(g, &p->type);
+				cgen_ident(g, p->name, NULL);
+				cgen_type_post(g, &p->type);
+			}
+		}
+	} else {
+		if (!uses_out_param)
+			cgen_write(g, "void");
+	}
+	if (uses_out_param) {
+		if (nparams) {
+			cgen_write(g, ",");
+			cgen_space(g);
+		}
+		/* write out param */
+		cgen_type_pre(g, ret_type);
+		cgen_write(g, "(*out__)"); /* TODO: fix this for named return values */
+		cgen_type_post(g, ret_type);
+			
+	}
+	cgen_write(g, ")");
+}
+
+static void cgen_type_post(CGenerator *g, Type *t) {
+	switch (t->kind) {
+	case TYPE_VOID:
+	case TYPE_BUILTIN:
+		break;
+	case TYPE_FN: {
+		Type *types = t->fn.types.data;
+		Type *ret_type = &types[0];
+		Type *param_types = types + 1;
+		assert(t->fn.types.len > 0);
+		size_t nparams = t->fn.types.len-1;
+		bool uses_out_param = cgen_fn_uses_out_param(ret_type);
+		cgen_write(g, ")");
+		cgen_fn_params(g, param_types, NULL, nparams, ret_type);
+		if (!uses_out_param) {
+			cgen_type_post(g, ret_type);
+		}
+		cgen_space(g);
+	} break;
+	case TYPE_TUPLE:
+		assert(0);
+		return;
+	case TYPE_ARR:
+		cgen_write(g, "[%lu]", t->arr.n);
+		cgen_type_post(g, t->arr.of);
+		break;
+	case TYPE_UNKNOWN: /* we should always do pre first */
+		assert(0);
+		break;
+	}
+}
+
+static bool cgen_fn_name(CGenerator *g, FnExpr *f, Location *where) {
+	if (f->name) {
+		/* TODO: check block  */
+		if (f->name == g->main_ident) {
+			cgen_write(g, "main__");
+			return true;
+		} else {
+			return cgen_ident(g, f->name, where);
+		}
+	} else {
+		cgen_anon_fn(g, f->id);
+		return true;
+	}
+}
+
+static bool cgen_fn_header(CGenerator *g, FnExpr *f) {
+	if (!f->name || g->block != NULL) {
+		cgen_write(g, "static "); /* anonymous functions only exist in this translation unit */
+	}
+	
+	bool uses_out_param = cgen_fn_uses_out_param(&f->ret_type);
+	size_t nparams = f->params.len;
+	if (uses_out_param) {
+		cgen_write(g, "void ");
+		cgen_fn_name(g, f, NULL);
+		cgen_fn_params(g, NULL, (Param*)f->params.data, nparams, &f->ret_type);
+	
+	} else {
+	    cgen_type_pre(g, &f->ret_type);
+		cgen_fn_name(g, f, NULL);
+		cgen_fn_params(g, NULL, (Param*)f->params.data, nparams, &f->ret_type);
+		cgen_type_post(g, &f->ret_type);
+	}
+	
+	return true;
+}
+
+static bool cgen_block_enter(CGenerator *g, Block *b) {
+	g->block = b;
+	return block_enter(b, &b->stmts);
+}
+
+static bool cgen_block_exit(CGenerator *g, Block *into) {
+	Block *b = g->block;
+	g->block = into;
+	return block_exit(b, &b->stmts);
+}
+
diff --git a/archive/cgen.c b/archive/cgen.c
new file mode 100644
index 0000000..7ff2308
--- /dev/null
+++ b/archive/cgen.c
@@ -0,0 +1,463 @@
+static void cgen_create(CGenerator *g, Identifiers *ids, FILE *c_out, FILE *h_out, const char *h_filename) {
+	g->c_out = c_out;
+	g->h_out = h_out;
+	g->anon_fn_count = 0;
+	g->anon_var_count = 0;
+	g->indent_level = 0;
+	g->block = NULL;
+    g->indent_next = true;
+	g->main_ident = ident_get(ids, "main");
+	
+	g->writing_to = CGEN_WRITING_TO_H;
+	cgen_write(g, "#include <stddef.h>\n"
+			   "#include <stdint.h>\n"
+			   "#include <string.h>\n");
+	
+	g->writing_to = CGEN_WRITING_TO_C;
+	cgen_write(g, "#include \"%s\"\n", h_filename);
+	cgen_writeln(g, ""); /* extra newline between includes and code */
+}
+
+static bool cgen_direct(CGenerator *g, DirectExpr *direct, Location where) {
+	switch (direct->which) {
+	case DIRECT_C: {
+		Expression *args = direct->args.data;
+		size_t nargs = direct->args.len;
+		if (nargs != 1) {
+			err_print(where, "Expected 1 argument to #C directive, but got %lu.", nargs);
+		}
+		/* TODO: compile-time constants */
+		if (args[0].kind != EXPR_STR_LITERAL) {
+			err_print(args[0].where, "Argument to #C directive must be a string literal.");
+		}
+		cgen_write(g, "%s", args[0].strl.str);
+	} break;
+	case DIRECT_COUNT:
+		assert(0);
+		return false;
+	}
+	return true;
+}
+
+
+/* generates C statements which must go before an expression. */
+static bool cgen_expr_pre(CGenerator *g, Expression *e) {
+	switch (e->kind) {
+	case EXPR_BINARY_OP:
+		if (!cgen_expr_pre(g, e->binary.lhs)) return false;
+		if (!cgen_expr_pre(g, e->binary.rhs)) return false;
+		/* TODO(eventually): Short-circuiting operators will need some work */
+		break;
+	case EXPR_UNARY_OP:
+		if (!cgen_expr_pre(g, e->unary.of)) return false;
+		break;
+	case EXPR_CALL: {
+		if (!cgen_expr_pre(g, e->call.fn)) return false;
+		arr_foreach(&e->call.args, Expression, arg)
+			if (!cgen_expr_pre(g, arg))
+				return false;
+		Type *fn_types = e->call.fn->type.fn.types.data;
+		Type *ret_type = &fn_types[0];
+		if (cgen_fn_uses_out_param(ret_type)) {
+			/* generate out call */
+			e->call.out_var = g->anon_var_count++;
+
+			/* declaration of out variable */
+			cgen_type_pre(g, ret_type);
+			cgen_anon_var(g, e->call.out_var);
+			cgen_type_post(g, ret_type);
+			cgen_writeln(g, ";");
+
+			cgen_expr(g, e->call.fn);
+			
+			cgen_write(g, "(");
+			arr_foreach(&e->call.args, Expression, arg) {
+				if (arg != e->call.args.data) {
+					cgen_write(g, ",");
+					cgen_space(g);
+				}
+				if (!cgen_expr(g, arg)) return false;
+			}
+			if (e->call.args.len) {
+				cgen_write(g, ",");
+				cgen_space(g);
+			}
+			cgen_write(g, "&");
+			cgen_anon_var(g, e->call.out_var);
+			cgen_writeln(g, ");");
+		}
+	} break;
+	default: break;
+	}
+	return true;
+}
+
+static bool cgen_expr(CGenerator *g, Expression *e) {
+	switch (e->kind) {
+	case EXPR_INT_LITERAL:
+		cgen_write(g, "%lld", e->intl);
+		break;
+	case EXPR_FLOAT_LITERAL:
+		/* TODO: more precision */
+		cgen_write(g, "%f", (double)e->floatl);
+		break;
+	case EXPR_STR_LITERAL:
+		cgen_write(g, "\"");
+		/* OPTIM: Maybe don't use i? this will probably be optimized by the compiler though... */
+		for (size_t i = 0; i < e->strl.len; i++) {
+			/* TODO: Print ordinary characters nicely */
+			cgen_write(g, "\\x%02x", e->strl.str[i]);
+		}
+		cgen_write(g, "\"");
+		break;
+	case EXPR_IDENT:
+		if (!cgen_ident(g, e->ident, &e->where)) return false;
+		break;
+	case EXPR_BINARY_OP:
+		cgen_write(g, "(");
+		if (!cgen_expr(g, e->binary.lhs)) return false;
+		switch (e->binary.op) {
+		case BINARY_PLUS:
+			cgen_write(g, "+");
+			break;
+		case BINARY_MINUS:
+			cgen_write(g, "-");
+			break;
+		case BINARY_SET:
+			cgen_write(g, "=");
+			break;
+		case BINARY_AT_INDEX:
+			cgen_write(g, "[");
+			break;
+		case BINARY_COMMA:
+			assert(0);
+			return false;
+		}
+		if (!cgen_expr(g, e->binary.rhs)) return false;
+		if (e->binary.op == BINARY_AT_INDEX) {
+			cgen_write(g, "]");
+		}
+		cgen_write(g, ")");
+		break;
+	case EXPR_UNARY_OP:
+		cgen_write(g, "(");
+		switch (e->unary.op) {
+		case UNARY_MINUS:
+			cgen_write(g, "-");
+			break;
+		}
+		if (!cgen_expr(g, e->unary.of)) return false;
+		cgen_write(g, ")");
+		break;
+	case EXPR_FN:
+		if (!cgen_fn_name(g, &e->fn, &e->where)) return false;
+		break;
+	case EXPR_CALL: {
+		Type *fn_types = e->call.fn->type.fn.types.data;
+		Type *ret_type = &fn_types[0];
+		if (cgen_fn_uses_out_param(ret_type)) { /* if there's an out parameter, */
+			cgen_anon_var(g, e->call.out_var); /* just use the variable we made earlier */
+		} else {
+			if (!cgen_expr(g, e->call.fn)) return false;
+			cgen_write(g, "(");
+			arr_foreach(&e->call.args, Expression, arg) {
+				if (arg != e->call.args.data) {
+					cgen_write(g, ",");
+					cgen_space(g);
+				}
+				if (!cgen_expr(g, arg)) return false;
+			}
+			cgen_write(g, ")");
+		}
+	} break;
+	case EXPR_DIRECT:
+		if (!cgen_direct(g, &e->direct, e->where)) return false;
+		break;
+	}
+	return true;
+}
+
+static bool cgen_stmt(CGenerator *g, Statement *s);
+
+static void cgen_zero_value(CGenerator *g, Type *t) {
+	switch (t->kind) {
+	case TYPE_VOID:	/* we should never need this */
+		assert(0);
+		break;
+	case TYPE_FN:
+		cgen_write(g, "NULL");
+		break;
+	case TYPE_ARR:
+		cgen_write(g, "{");
+		cgen_zero_value(g, t->arr.of);
+		cgen_write(g, "}");
+		break;
+	case TYPE_TUPLE:
+		assert(0);
+		break;
+	case TYPE_BUILTIN:
+		if (type_builtin_is_numerical(t->builtin)) {
+			cgen_write(g, "0");
+		} else {
+			assert(0);
+		}
+		break;
+	case TYPE_UNKNOWN:
+		assert(0);
+		break;
+	}
+}
+
+static bool cgen_decl(CGenerator *g, Declaration *d) {
+	size_t i = d->idents.len;
+	if (d->flags & DECL_FLAG_HAS_EXPR) {
+		if (!cgen_expr_pre(g, &d->expr))
+			return false;
+	}
+	/* because , is left-associative, we want to go backwards */
+	arr_foreach_reverse(&d->idents, Identifier, ident) {
+		Type *type;
+		if (d->idents.len > 1) {
+			/* it's a tuple! */
+			type = &(((Type*)d->type.tuple.data)[--i]);
+		} else {
+			type = &d->type;
+			if (type->kind == TYPE_TUPLE) {
+				/* TODO */
+				err_print(d->where, "Direct declaration of tuples is not supported yet.");
+				return false;
+			}
+		}
+		if (type->kind == TYPE_ARR) {
+			/* if you do a : [3]int; translates into int64_t av___23[3] = {0}; int64_t *a = av___23; */
+			int has_expr = d->flags & DECL_FLAG_HAS_EXPR;
+			unsigned long var;
+			if (!has_expr) {
+				/* int64_t av___23[3] = {0}; */
+				var = g->anon_var_count++;
+				cgen_type_pre(g, type);
+				cgen_anon_var(g, var);
+				cgen_type_post(g, type);
+				cgen_space(g);
+				cgen_write(g, "=");
+				cgen_space(g);
+				cgen_zero_value(g, type);
+				cgen_writeln(g, ";");
+			}
+			/* int64_t *a = av___23; */
+			cgen_type_pre(g, type->arr.of);
+			cgen_write(g, "(*");
+			cgen_ident(g, *ident, NULL);
+			cgen_write(g, ")");
+			cgen_type_post(g, type->arr.of);
+			cgen_space(g);
+			cgen_write(g, "=");
+			cgen_space(g);
+			if (has_expr) {
+				if (!cgen_expr(g, &d->expr)) return false;
+			} else {
+				cgen_anon_var(g, var);
+			}
+			cgen_writeln(g, ";");
+			return true;
+		}
+		
+		cgen_type_pre(g, type);
+		if (d->flags & DECL_FLAG_CONST) { /* TODO: remove this (never actually produce constants) */
+			cgen_space(g);
+			cgen_write(g, "const");
+			cgen_space(g);
+		}
+		cgen_ident(g, *ident, NULL);
+		cgen_type_post(g, type);
+		cgen_space(g);
+		cgen_write(g, "=");
+		cgen_space(g);
+		if (d->flags & DECL_FLAG_HAS_EXPR) {
+			Expression *expr = &d->expr;
+			if (d->idents.len > 1) {
+				if (expr->kind == EXPR_BINARY_OP && expr->binary.op == BINARY_COMMA) {
+					if (!cgen_expr(g, expr->binary.rhs)) return false;
+					expr = expr->binary.lhs; /* ((3,4),5),6 => (3,4),5 */
+				} else {
+					/* last iteration */
+					if (!cgen_expr(g, expr)) return false;
+				}
+
+			} else {
+				if (!cgen_expr(g, expr)) return false;
+			}
+		} else {
+			cgen_zero_value(g, type);
+		}
+		cgen_write(g, "; ");
+	}
+	cgen_writeln(g, "");
+	return true;
+}
+
+static bool cgen_stmt(CGenerator *g, Statement *s) {
+	switch (s->kind) {
+	case STMT_EXPR:
+		if (!cgen_expr(g, &s->expr))
+			return false;
+		cgen_writeln(g, ";");
+		break;
+	case STMT_DECL: {
+		Declaration *d = &s->decl;
+		if ((d->flags & DECL_FLAG_HAS_EXPR) && (d->flags & DECL_FLAG_CONST))
+			if (d->expr.kind == EXPR_FN)
+				return true; /* already dealt with below */
+			
+		return cgen_decl(g, &s->decl);
+	}
+	}
+	return true;
+}
+
+static bool cgen_fns_in_stmt(CGenerator *g, Statement *s);
+
+typedef struct {
+	bool is_return; /* true => this is a function return */
+	unsigned long var_no; /* if is_return = false, set the anonymous variable with this number to the return value. */
+	const char *exit_with; /* how to exit this block in C, e.g. "break" (not needed if is_return = true). */
+} BlockExitKind;
+
+/* generates a block but not the functions, etc. inside it */
+static bool cgen_block(CGenerator *g, Block *b, BlockExitKind *exit_kind) {
+	bool success = true;
+	cgen_writeln(g, "{");
+	g->indent_level++;
+	arr_foreach(&b->stmts, Statement, s) {
+		if (!cgen_stmt(g, s))
+			success = false;
+	}
+	if (exit_kind->is_return) {
+		/* generate return from function */
+		Expression *ret = b->ret_expr;
+		if (ret && cgen_fn_uses_out_param(&ret->type)) {
+			if (ret->type.kind == TYPE_ARR) {
+				/* returning possibly multi-dimensional arrays */
+				size_t total_size = 1; /* product of all dimensions */
+				Type *type;
+				for (type = &ret->type; type->kind == TYPE_ARR; type = type->arr.of)
+					total_size *= type->arr.n;
+				/* type is now the base type of the array, e.g. [3][3][3]fn() => fn() */
+				cgen_write(g, "memcpy(*out__, ");
+				if (!cgen_expr(g, b->ret_expr)) return false;
+				cgen_write(g, ", %lu * sizeof(", total_size);
+				cgen_type_pre(g, type);
+				cgen_type_post(g, type);
+				cgen_writeln(g, ")); return;");
+			} else {
+				cgen_write(g, "*out__ = ");
+				if (!cgen_expr(g, b->ret_expr)) return false;
+				cgen_writeln(g, ";");
+				cgen_writeln(g, "return;");
+			}
+		} else {
+			cgen_write(g, "return");
+			if (b->ret_expr) {
+				cgen_write(g, " ");
+				if (!cgen_expr(g, b->ret_expr)) return false;
+			}
+			cgen_writeln(g, ";");
+		}
+	} else {
+		err_print(b->ret_expr->where, "TODO");
+		return false;
+	}
+	if (success) {
+		g->indent_level--;
+		cgen_writeln(g, "}");
+	}
+	return success;
+}
+
+/* Generates function definition, and the definitions of all functions inside this */
+static bool cgen_fn(CGenerator *g, FnExpr *f) {
+	if (!cgen_fn_header(g, f)) return false;
+	Block *prev_block = g->block;
+	cgen_block_enter(g, &f->body);
+	cgen_space(g);
+	BlockExitKind e_kind;
+	e_kind.is_return = 1;
+	if (!cgen_block(g, &f->body, &e_kind)) return false;
+
+	bool ret = true;
+	arr_foreach(&f->body.stmts, Statement, stmt) {
+		if (!cgen_fns_in_stmt(g, stmt)) ret = false;
+	}
+	cgen_block_exit(g, prev_block);
+	return ret;
+}
+
+static bool cgen_fns_in_expr(CGenerator *g, Expression *e) {
+	switch (e->kind) {
+	case EXPR_FN:
+		return cgen_fn(g, &e->fn);
+	case EXPR_CALL:
+		return cgen_fns_in_expr(g, e->call.fn); 
+	default: return true;
+	}
+}
+
+static bool cgen_fns_in_stmt(CGenerator *g, Statement *s) {
+	switch (s->kind) {
+	case STMT_EXPR:
+		if (s->expr.kind == EXPR_FN) {
+			warn_print(s->where, "Statement of function has no effect (try assigning the function to a variable).");
+		} else {
+			return cgen_fns_in_expr(g, &s->expr);
+		}
+		break;
+	case STMT_DECL: {
+		Declaration *d = &s->decl;
+		if (d->flags & DECL_FLAG_HAS_EXPR)
+			return cgen_fns_in_expr(g, &d->expr);
+	} break;
+	}
+	return true;
+}
+
+/* generate a statement at top level, including any functions in it. */
+static bool cgen_stmt_top(CGenerator *g, Statement *s) {
+	if (!cgen_fns_in_stmt(g, s)) return false;
+	switch (s->kind) {
+	case STMT_EXPR: {
+		Expression *e = &s->expr;
+		bool ignored = true;
+		switch (e->kind) {
+		case EXPR_DIRECT:
+			switch (e->direct.which) {
+			case DIRECT_C:
+				ignored = false;
+				cgen_direct(g, &e->direct, e->where);
+				break;
+			case DIRECT_COUNT: assert(0); break;
+			}
+		default: break;
+		}
+		if (ignored)
+			warn_print(e->where, "Expression at top level currently ignored."); /* TODO */
+	} break;
+	case STMT_DECL: break;
+	}
+	return true;
+}
+
+static bool cgen_file(CGenerator *g, ParsedFile *f) {
+	cgen_write_line_comment(g, "toc");
+	bool ret = true;
+	if (!cgen_decls_file(g, f)) return false;
+	arr_foreach(&f->stmts, Statement, s) {
+		if (!cgen_stmt_top(g, s)) return false;
+	}
+	g->writing_to = CGEN_WRITING_TO_C;
+	/* write actual main function */
+	cgen_write(g, "\nint main(void) {\n"
+			   "\tmain__();\n"
+			   "\treturn 0;\n"
+			   "}\n");
+	return ret;
+}
diff --git a/archive/decls_cgen.c b/archive/decls_cgen.c
new file mode 100644
index 0000000..a596f53
--- /dev/null
+++ b/archive/decls_cgen.c
@@ -0,0 +1,106 @@
+/* C declarations of functions and global variables. e must be a function expression */
+static bool cgen_decl_fn(CGenerator *g, FnExpr *f) {
+	/* assign an ID to the function */
+	if (f->name && g->block == NULL) {
+		f->id = f->name->c_fn_reps++;
+	} else {
+		f->id = g->anon_fn_count++;
+	}
+	
+	if (!cgen_fn_header(g, f)) return false;
+	cgen_writeln(g, ";");
+	return true;
+}
+
+static bool cgen_decls_stmt(CGenerator *g, Statement *s);
+
+static bool cgen_decls_expr(CGenerator *g, Expression *e) {
+	switch (e->kind) {
+	case EXPR_FN: {
+		FnExpr *f = &e->fn;
+		if (f->name && g->block == NULL) { /* write named function prototypes in global scope to header file */
+			g->writing_to = CGEN_WRITING_TO_H;
+		} else {
+			g->writing_to = CGEN_WRITING_TO_C;
+		}
+		if (!cgen_decl_fn(g, f))
+			return false;
+		g->writing_to = CGEN_WRITING_TO_C;
+
+		
+		bool ret = true;
+		Block *prev_block = g->block;
+		cgen_block_enter(g, &f->body);
+		arr_foreach(&f->body.stmts, Statement, s) {
+			if (!cgen_decls_stmt(g, s))
+				ret = false;
+		}
+		cgen_block_exit(g, prev_block);
+		return ret;
+	}
+	case EXPR_CALL:
+		if (!cgen_decls_expr(g, e->call.fn))
+			return false;
+		arr_foreach(&e->call.args, Expression, arg) {
+			if (!cgen_decls_expr(g, arg))
+				return false;
+		}
+		break;
+	default: break;
+	}
+	return true;
+}
+
+
+static bool cgen_expr(CGenerator *g, Expression *e);
+static bool cgen_decls_stmt(CGenerator *g, Statement *s) {
+	switch (s->kind) {
+	case STMT_EXPR:
+		return cgen_decls_expr(g, &s->expr);
+	case STMT_DECL: {
+		Declaration *d = &s->decl;
+		bool is_const_fn = (d->flags & DECL_FLAG_HAS_EXPR) && (d->flags & DECL_FLAG_CONST)
+			&& d->expr.kind == EXPR_FN;
+
+		if (is_const_fn) {
+			/* e.g. foo @= fn() {}; (we want to set the function's name to "foo") */
+			d->expr.fn.name = *(Identifier*)d->idents.data;
+		}
+
+		if (d->flags & DECL_FLAG_HAS_EXPR) {
+			cgen_decls_expr(g, &d->expr);
+		}
+		
+		if (!is_const_fn) {
+			if (g->block == NULL) {
+				/* declare this/these global variable(s) */
+				arr_foreach(&d->idents, Identifier, i) {
+					cgen_type_pre(g, &d->type);
+					cgen_ident(g, *i, NULL);
+					cgen_type_post(g, &d->type);
+					if (d->flags & DECL_FLAG_HAS_EXPR) { /* TODO: check if expr is const */
+						cgen_space(g);
+						cgen_write(g, "=");
+						cgen_space(g);
+						if (!cgen_expr(g, &d->expr))
+							return false;
+					}
+					cgen_write(g, ";");
+					cgen_space(g);
+				}
+				cgen_writeln(g, "");
+			}
+		}
+		
+	} break;
+	}
+	return true;
+}
+
+static bool cgen_decls_file(CGenerator *g, ParsedFile *f) {
+	arr_foreach(&f->stmts, Statement, s) {
+		if (!cgen_decls_stmt(g, s))
+			return false;
+	}
+	return true;
+}