begin work on a d20 framework

dice/CMakeLists.txt

@@ -0,0 +1,15 @@
+CMAKE_MINIMUM_REQUIRED(VERSION 3.2)
+
+SET(TARGET "d20-dice")
+SET(SOURCE
+  "src/dice.c"
+  )
+
+PKG_CHECK_MODULES(DICE REQUIRED libdice)
+
+INCLUDE_DIRECTORIES(${DICE_INCLUDE_DIRS})
+
+ADD_EXECUTABLE(${TARGET} ${SOURCE})
+TARGET_LINK_LIBRARIES(${TARGET} ${DICE_LIBRARIES})
+
+INSTALL(TARGETS ${TARGET} DESTINATION ${LIB_DIR})

dice/src/dice.c

@@ -0,0 +1,104 @@
+#include <stdio.h>
+#include <string.h>
+#include <stdbool.h>
+#include <stdlib.h>
+
+#include <getopt.h>
+
+#include <dice.h>
+
+static bool evaluate_expression(char const *s)
+{
+    dice_expression_t e = dice_expression_new();
+    int error = 0;
+    int64_t result = 0;
+    bool ret = false;
+
+    if (e == NULL) {
+        fprintf(stderr, "oom\n");
+        goto error;
+    }
+
+    if (!dice_expression_parse(e, s, &error)) {
+        fprintf(stderr, "failed to parse expression `%s` around column %d\n",
+                s, error
+            );
+        goto error;
+    }
+
+    if (!dice_expression_roll(e, &result)) {
+        fprintf(stderr, "failed to evaluate expression `%s`", s);
+        goto error;
+    }
+
+    printf("%ld\n", result);
+
+    ret = true;
+
+error:
+
+    dice_expression_free(e);
+    return ret;
+}
+
+int main(int ac, char **av)
+{
+    static char const *optstr = "e:";
+    static struct option opts[] = {
+        { "expression", required_argument, NULL, 'e' },
+        { NULL, 0, NULL, 0}
+    };
+
+    int c = 0, i = 0;
+    FILE *f = NULL;
+    char *buf = NULL;
+    size_t buflen = 0;
+    bool ret = false;
+
+    while ((c = getopt_long(ac, av, optstr, opts, NULL)) != -1) {
+        switch (c) {
+        case 'e':
+        {
+            if (!evaluate_expression(optarg)) {
+                exit(3);
+            }
+        } break;
+
+        default:
+        {
+            fprintf(stderr, "invalid option specified\n");
+            exit(3);
+        } break;
+
+        }
+    }
+
+    /* parse remainderes
+     */
+    if (optind < ac) {
+        f = open_memstream(&buf, &buflen);
+        if (f == NULL) {
+            exit(3);
+        }
+
+        for (i = optind; i < ac; i++) {
+            fprintf(f, "%s", av[i]);
+            if (i < ac) {
+                fputc(' ', f);
+            }
+        }
+
+        fclose(f);
+
+        ret = evaluate_expression(buf);
+        free(buf);
+        buf = NULL;
+        buflen = 0;
+
+        if (!ret) {
+            exit(3);
+        }
+    }
+
+    return 0;
+}