make EVERYTHING static

main.c

@@ -22,10 +22,10 @@ typedef struct Tok {
 } Tok;
 
 #define TOKS_CAP 65536
-Tok toks[TOKS_CAP];
-size_t toks_size = 0;
+static Tok toks[TOKS_CAP];
+static size_t toks_size = 0;
 
-uint8_t op_prec[256] = {
+static uint8_t op_prec[256] = {
 	['('] = 0, /* A precedence of 0 is reserved for delimiters. */
 	[')'] = 0,
 	[','] = 0,
@@ -37,7 +37,7 @@ uint8_t op_prec[256] = {
 };
 #define OP_PREC(tok_char) (op_prec[(size_t)tok_char])
 
-enum {
+static enum {
 	OrderLtr,
 	OrderRtl,
 } op_order[256] = {
@@ -54,12 +54,27 @@ enum {
 #define IS_FLOAT(c) ((c >= '0' && c <= '9') || c == '.')
 #define IS_ALPHA(c) ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z'))
 
-void push_tok(Tok t) {
+typedef struct Function {
+	const char *name;
+	real (*func)(real *args);
+	size_t n_args;
+} Function;
+
+#define FUNCTIONS_CAP 256
+static Function functions[FUNCTIONS_CAP];
+static size_t functions_size = 0;
+
+static void push_tok(Tok t) {
 	if (toks_size+1 < TOKS_CAP)
 		toks[toks_size++] = t;
 }
 
-void tokenize(char *expr) {
+static void add_func(const char *name, real (*func)(real *args), size_t n_args) {
+	if (functions_size+1 < FUNCTIONS_CAP)
+		functions[functions_size++] = (Function){.name = name, .func = func, .n_args = n_args};
+}
+
+static void tokenize(char *expr) {
 	push_tok((Tok){.kind = TokOp, .Char = '('});
 
 	size_t paren_depth = 0;
@@ -137,7 +152,7 @@ void tokenize(char *expr) {
 	push_tok((Tok){.kind = TokOp, .Char = ')'});
 }
 
-void print_toks() {
+static void print_toks() {
 	for (size_t i = 0; i < toks_size; i++) {
 		switch (toks[i].kind) {
 		case TokOp:
@@ -162,12 +177,12 @@ void print_toks() {
 }
 
 /* Delete tokens from begin to end (excluding end itself). */
-void del_toks(Tok *begin, Tok *end) {
+static void del_toks(Tok *begin, Tok *end) {
 	memmove(begin, end, (toks_size - (end - toks)) * sizeof(Tok));
 	toks_size -= end - begin;
 }
 
-real eval(Tok *t) {
+static real eval(Tok *t) {
 	if (!(t[0].kind == TokOp && OP_PREC(t[0].Char) == 0)) {
 		fprintf(stderr, "Error: expected delimiter at beginning of expression\n");
 		exit(1);
@@ -222,22 +237,23 @@ real eval(Tok *t) {
 			t -= 2;
 
 			real outer_res;
-			if (strcmp(t[1].Str, "sqrt") == 0) {
-				if (arg_results_size != 1) {
-					fprintf(stderr, "Error: function sqrt() requires exactly 1 argument\n");
-					exit(1);
+			bool func_found = false;
+			for (size_t i = 0; i < functions_size; i++) {
+				if (strcmp(t[1].Str, functions[i].name) == 0) {
+					func_found = true;
+					if (arg_results_size != functions[i].n_args) {
+						const char *plural = functions[i].n_args == 1 ? "" : "s";
+						fprintf(stderr, "Error: function %s() requires exactly 1 argument%s\n", functions[i].name, plural);
+						exit(1);
+					}
+					outer_res = functions[i].func(arg_results);
 				}
-				outer_res = sqrt(arg_results[0]);
-			} else if (strcmp(t[1].Str, "pow") == 0) {
-				if (arg_results_size != 2) {
-					fprintf(stderr, "Error: function pow() requires exactly 2 arguments\n");
-					exit(1);
-				}
-				outer_res = pow(arg_results[0], arg_results[1]);
-			} else {
-				fprintf(stderr, "Error: unknown function name: %s\n", t[1].Str);
+			}
+			if (!func_found) {
+				fprintf(stderr, "Error: unknown function: %s()\n", t[1].Str);
 				exit(1);
 			}
+
 			t[1].kind = TokNum;
 			t[1].Num = outer_res;
 		}
@@ -282,18 +298,31 @@ real eval(Tok *t) {
 	}
 }
 
-void cleanup() {
+static void cleanup() {
 	for (size_t i = 0; i < toks_size; i++) {
 		if (toks[i].kind == TokFunc)
 			free(toks[i].Str);
 	}
 }
 
+static real fn_sqrt(real *args)  { return sqrt(args[0]); }
+static real fn_pow(real *args)   { return pow(args[0], args[1]); }
+static real fn_mod(real *args)   { return fmod(args[0], args[1]); }
+static real fn_round(real *args) { return round(args[0]); }
+static real fn_floor(real *args) { return floor(args[0]); }
+static real fn_ceil(real *args)  { return ceil(args[0]); }
+
 int main(int argc, char **argv) {
 	if (argc != 2 || strcmp(argv[1], "-h") == 0 || strcmp(argv[1], "--help") == 0) {
 		fprintf(stderr, "Usage: ./exp \"<expression>\"\n");
 		exit(1);
 	}
+	add_func("sqrt", fn_sqrt, 1);
+	add_func("pow", fn_pow, 2);
+	add_func("mod", fn_mod, 2);
+	add_func("round", fn_round, 1);
+	add_func("floor", fn_floor, 1);
+	add_func("ceil", fn_ceil, 1);
 	tokenize(argv[1]);
 	print_toks();
 	real res = eval(toks);