Address #219.

Adds several shorthands to the C API.

CHANGELOG.md

@@ -27,6 +27,7 @@ All notable changes to this project will be documented in this file.
 - Add `janet_in` to C API.
 - Add `truthy?`
 - Add `os/environ`
+- Add `buffer/fill`
 - Use `(doc)` with no arguments to see available bindings and dynamic bindings.
 - `jpm` will use `CC` and `AR` environment variables when compiling programs.
 - Add `comptime` macro for compile time evaluation.

src/core/capi.c

@@ -168,6 +168,30 @@ bad:
     janet_panicf("bad slot #%d, expected non-negative 32 bit signed integer, got %v", n, x);
 }
 
+JanetAbstract janet_checkabstract(Janet x, const JanetAbstractType *at) {
+    if (!janet_checktype(x, JANET_ABSTRACT)) return NULL;
+    JanetAbstract a = janet_unwrap_abstract(x);
+    if (janet_abstract_type(a) != at) return NULL;
+    return a;
+}
+
+static int janet_strlike_cmp(JanetType type, Janet x, const char *cstring) {
+    if (janet_type(x) != type) return 0;
+    return !janet_cstrcmp(janet_unwrap_string(x), cstring);
+}
+
+int janet_keyeq(Janet x, const char *cstring) {
+    return janet_strlike_cmp(JANET_KEYWORD, x, cstring);
+}
+
+int janet_streq(Janet x, const char *cstring) {
+    return janet_strlike_cmp(JANET_STRING, x, cstring);
+}
+
+int janet_symeq(Janet x, const char *cstring) {
+    return janet_strlike_cmp(JANET_SYMBOL, x, cstring);
+}
+
 int32_t janet_getinteger(const Janet *argv, int32_t n) {
     Janet x = argv[n];
     if (!janet_checkint(x)) {

src/include/janet.h

@@ -663,6 +663,7 @@ struct Janet {
 JANET_API int janet_checkint(Janet x);
 JANET_API int janet_checkint64(Janet x);
 JANET_API int janet_checksize(Janet x);
+JANET_API JanetAbstract janet_checkabstract(Janet x, const JanetAbstractType *at);
 #define janet_checkintrange(x) ((x) == (int32_t)(x))
 #define janet_checkint64range(x) ((x) == (int64_t)(x))
 #define janet_unwrap_integer(x) ((int32_t) janet_unwrap_number(x))
@@ -1320,6 +1321,9 @@ JANET_API void janet_put(Janet ds, Janet key, Janet value);
 JANET_API void janet_putindex(Janet ds, int32_t index, Janet value);
 #define janet_flag_at(F, I) ((F) & ((1ULL) << (I)))
 JANET_API Janet janet_wrap_number_safe(double x);
+JANET_API int janet_keyeq(Janet x, const char *cstring);
+JANET_API int janet_streq(Janet x, const char *cstring);
+JANET_API int janet_symeq(Janet x, const char *cstring);
 
 /* VM functions */
 JANET_API int janet_init(void);