Add a REPL for toying around

.gitignore

@@ -1,6 +1,7 @@
 # Build files
 /build
-/ell
+/interpreter
+/repl
 
 # Qt Creator files
 /CMakeLists.txt.user*

Makefile

@@ -4,7 +4,7 @@ all: interpreter
 interpreter: interpreter.c ell.c
 	$(CC) $(CFLAGS) $< -o $@
 repl: repl.c ell.c
-	$(CC) $(CFLAGS) $< -o $@
+	$(CC) $(CFLAGS) $< -o $@ -lreadline
 clean:
 	rm -f interpreter repl
 .PHONY: all clean

repl.c

@@ -0,0 +1,73 @@
+/*
+ * repl.c: test REPL
+ *
+ * Copyright (c) 2017, Přemysl Janouch <p.janouch@gmail.com>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include "ell.c"
+#include <readline/readline.h>
+#include <readline/history.h>
+
+int
+main (int argc, char *argv[]) {
+	(void) argc;
+
+	struct context ctx;
+	context_init (&ctx);
+	if (!init_runtime_library (&ctx))
+		printf ("%s\n", "runtime library initialization failed");
+
+	using_history ();
+	const char *slash = strrchr (argv[0], '/');
+	rl_readline_name = slash ? ++slash : argv[0];
+
+	char *line;
+	while ((line = readline ("> "))) {
+		struct parser parser;
+		parser_init (&parser, line, strlen (line));
+		add_history (line);
+
+		const char *e = NULL;
+		struct item *program = parser_run (&parser, &e);
+		free (line);
+		if (e) {
+			printf ("\x1b[31m%s: %s\x1b[0m\n", "parse error", e);
+			parser_free (&parser);
+			continue;
+		}
+		parser_free (&parser);
+
+		struct item *result = NULL;
+		(void) execute (&ctx, program, &result);
+		item_free_list (program);
+
+		const char *failure = ctx.error;
+		if (ctx.memory_failure)
+			failure = "memory allocation failure";
+		if (failure) {
+			printf ("\x1b[31m%s: %s\x1b[0m\n", "runtime error", failure);
+			free (ctx.error);
+			ctx.error = NULL;
+			ctx.memory_failure = false;
+		} else {
+			print_tree (result, 0);
+			putchar ('\n');
+			item_free_list (result);
+		}
+	}
+	context_free (&ctx);
+	return 0;
+}