add a REPL

cmd/main.c

@@ -10,10 +10,18 @@
 #include <stdio.h>
 #include <string.h>
 
+#ifdef __unix__
+#define USE_READLINE
+#include <unistd.h>
+#include <readline/readline.h>
+#include <readline/history.h>
+#endif
+
 static int do_print_bytecode = 0;
 static int do_print_tokens = 0;
 static int do_step = 0;
 static int do_serialize_bytecode = 0;
+static int do_repl = 0;
 static char *input_filename = "-";
 
 static int parse_text(FILE *inf, struct l2_io_writer *w) {
@@ -35,6 +43,7 @@ static int parse_text(FILE *inf, struct l2_io_writer *w) {
 	if (l2_parse_program(&lexer, &gen, &err) < 0) {
 		fprintf(stderr, "Parse error: %s:%i:%i: %s\n",
 				input_filename, err.line, err.ch, err.message);
+		l2_parse_error_free(&err);
 		l2_gen_free(&gen);
 		fclose(inf);
 		return -1;
@@ -62,6 +71,65 @@ static void step_through(struct l2_vm *vm) {
 	}
 }
 
+static int repl() {
+	struct l2_io_mem_writer w = {
+		.w.write = l2_io_mem_write,
+	};
+
+	struct l2_io_mem_reader r = {
+		.r.read = l2_io_mem_read,
+	};
+
+	struct l2_lexer lexer;
+
+	struct l2_generator gen;
+	l2_gen_init(&gen, &w.w);
+
+	struct l2_vm vm;
+	l2_vm_init(&vm, NULL, 0);
+
+	while (1) {
+		char line[4096];
+#ifdef USE_READLINE
+		char *rline = readline("> ");
+		if (rline == NULL) return -1;
+		if (rline[0] == '\0') continue;
+		snprintf(line, sizeof(line), "print (%s)", rline);
+		free(rline);
+#else
+		char rline[4096];
+		if (fgets(rline, sizeof(rline), stdin) == NULL) return -1;
+		if (rline[0] == '\n' && rline[1] == '\0') continue;
+		snprintf(line, sizeof(line), "print (%s)", rline);
+#endif
+
+		r.idx = 0;
+		r.len = strlen(line);
+		r.mem = line;
+		l2_lexer_init(&lexer, &r.r);
+
+		size_t prev_len = w.len;
+
+		struct l2_parse_error err;
+		if (l2_parse_program(&lexer, &gen, &err) < 0) {
+			fprintf(stderr, "Parse error: %s\n", err.message);
+			l2_parse_error_free(&err);
+			w.len = prev_len;
+		} else if (w.len > 0) {
+			vm.ops = w.mem;
+			vm.opcount = w.len / sizeof(l2_word);
+
+			while (vm.iptr < vm.opcount) {
+				l2_vm_step(&vm);
+			}
+
+			l2_vm_gc(&vm);
+		}
+	}
+
+	return 0;
+}
+
 static void usage(const char *argv0) {
 	printf("Usage: %s [options] [input|-]\n", argv0);
 	printf("\n");
@@ -70,6 +138,7 @@ static void usage(const char *argv0) {
 	printf("  --bytecode:        Print the generated bytecode, don't execute\n");
 	printf("  --tokens:          Print the tokens as the program is parsed, don't execute\n");
 	printf("  --step:            Step through the program\n");
+	printf("  --repl:            Start a repl\n");
 	printf("  --output,-o <out>: Write bytecode to file\n");
 }
 
@@ -78,6 +147,10 @@ int main(int argc, char **argv) {
 	FILE *inf = stdin;
 	FILE *outbc = NULL;
 
+#ifdef __unix__
+	do_repl = isatty(0);
+#endif
+
 	int dashes = 0;
 	for (int i = 1; i < argc; ++i) {
 		if (!dashes && strcmp(argv[i], "--help") == 0) {
@@ -89,6 +162,8 @@ int main(int argc, char **argv) {
 			do_print_tokens = 1;
 		} else if (!dashes && strcmp(argv[i], "--step") == 0) {
 			do_step = 1;
+		} else if (!dashes && strcmp(argv[i], "--repl") == 0) {
+			do_repl = 1;
 		} else if (!dashes && (
 				strcmp(argv[i], "--output") == 0 || strcmp(argv[i], "-o") == 0)) {
 			if (i == argc - 1) {
@@ -110,9 +185,11 @@ int main(int argc, char **argv) {
 		} else if (strcmp(argv[i], "--") == 0) {
 			dashes = 1;
 		} else if (strcmp(argv[i], "-") == 0) {
+			do_repl = 0;
 			input_filename = "-";
 			inf = stdin;
 		} else if (!was_inf_set) {
+			do_repl = 0;
 			input_filename = argv[i];
 			inf = fopen(argv[i], "r");
 			was_inf_set = 1;
@@ -127,10 +204,18 @@ int main(int argc, char **argv) {
 		}
 	}
 
-	struct l2_io_mem_writer bytecode_writer = {0};
-	bytecode_writer.w.write = l2_io_mem_write;
+	if (do_repl) {
+		if (repl() < 0) {
+			return 1;
+		}
+
+		return 0;
+	}
+
+	struct l2_io_mem_writer bytecode_writer = {
+		.w.write = l2_io_mem_write,
+	};
 
-	// 
 	int headerbyte = fgetc(inf);
 	if (headerbyte == EOF || ungetc(headerbyte, inf) == EOF) {
 		fprintf(stderr, "%s: Reading file failed.\n", input_filename);

include/lang2/loader.h

@@ -7,6 +7,6 @@
 #include <stdio.h>
 
 int l2_bc_serialize(FILE *outf, l2_word *data, size_t len);
-int l2_bc_load(FILE *outf, struct l2_io_writer *w);
+int l2_bc_load(FILE *inf, struct l2_io_writer *w);
 
 #endif

lib/loader.c

@@ -77,6 +77,5 @@ int l2_bc_load(FILE *inf, struct l2_io_writer *w) {
 				((unsigned int)buffer[i + 3]) << 0;
 			l2_bufio_put_n(&writer, &word, 4);
 		}
-
 	}
 }