Add tostring method for abstract types.

This lets abstract types customize how they
print for debugging.

src/core/inttypes.c

@@ -23,6 +23,7 @@
 #include <errno.h>
 #include <stdlib.h>
 #include <limits.h>
+#include <inttypes.h>
 
 #ifndef JANET_AMALG
 #include <janet.h>
@@ -45,6 +46,18 @@ static void int64_unmarshal(void *p, JanetMarshalContext *ctx) {
     *((int64_t *)p) = janet_unmarshal_int64(ctx);
 }
 
+static void it_s64_tostring(void *p, JanetBuffer *buffer) {
+    char str[32];
+    sprintf(str, "<core/s64 %" PRId64 ">", *((int64_t *)p));
+    janet_buffer_push_cstring(buffer, str);
+}
+
+static void it_u64_tostring(void *p, JanetBuffer *buffer) {
+    char str[32];
+    sprintf(str, "<core/u64 %" PRIu64 ">", *((uint64_t *)p));
+    janet_buffer_push_cstring(buffer, str);
+}
+
 static const JanetAbstractType it_s64_type = {
     "core/s64",
     NULL,
@@ -52,7 +65,8 @@ static const JanetAbstractType it_s64_type = {
     it_s64_get,
     NULL,
     int64_marshal,
-    int64_unmarshal
+    int64_unmarshal,
+    it_s64_tostring
 };
 
 static const JanetAbstractType it_u64_type = {
@@ -62,7 +76,8 @@ static const JanetAbstractType it_u64_type = {
     it_u64_get,
     NULL,
     int64_marshal,
-    int64_unmarshal
+    int64_unmarshal,
+    it_u64_tostring
 };
 
 int64_t janet_unwrap_s64(Janet x) {

src/core/io.c

@@ -58,6 +58,7 @@ JanetAbstractType cfun_io_filetype = {
     io_file_get,
     NULL,
     NULL,
+    NULL,
     NULL
 };
 

src/core/parse.c

@@ -650,6 +650,7 @@ static JanetAbstractType janet_parse_parsertype = {
     parserget,
     NULL,
     NULL,
+    NULL,
     NULL
 };
 

src/core/peg.c

@@ -986,6 +986,7 @@ static JanetAbstractType peg_type = {
     NULL,
     NULL,
     NULL,
+    NULL,
     NULL
 };
 

src/core/pp.c

@@ -201,8 +201,14 @@ void janet_description_b(JanetBuffer *buffer, Janet x) {
             janet_escape_buffer_b(buffer, janet_unwrap_buffer(x));
             return;
         case JANET_ABSTRACT: {
-            const char *n = janet_abstract_type(janet_unwrap_abstract(x))->name;
+            void *p = janet_unwrap_abstract(x);
+            const JanetAbstractType *at = janet_abstract_type(p);
+            if (at->tostring) {
+                at->tostring(p, buffer);
+            } else {
+                const char *n = at->name;
                 string_description_b(buffer, n, janet_unwrap_abstract(x));
+            }
             return;
         }
         case JANET_CFUNCTION: {
@@ -456,38 +462,18 @@ static void pushtypes(JanetBuffer *buffer, int types) {
     }
 }
 
-/* Helper function for formatting strings. Useful for generating error messages and the like.
- * Similar to printf, but specialized for operating with janet. */
-const uint8_t *janet_formatc(const char *format, ...) {
-    va_list args;
-    int32_t len = 0;
-    int32_t i;
-    const uint8_t *ret;
-    JanetBuffer buffer;
-    JanetBuffer *bufp = &buffer;
-
-    /* Calculate length */
-    while (format[len]) len++;
-
-    /* Initialize buffer */
-    janet_buffer_init(bufp, len);
-
-    /* Start args */
-    va_start(args, format);
-
-    /* Iterate length */
-    for (i = 0; i < len; i++) {
-        uint8_t c = format[i];
-        switch (c) {
+void janet_formatb(JanetBuffer *bufp, const char *format, va_list args) {
+    for (const char *c = format; *c; c++) {
+        switch (*c) {
             default:
-                janet_buffer_push_u8(bufp, c);
+                janet_buffer_push_u8(bufp, *c);
                 break;
             case '%': {
-                if (i + 1 >= len)
+                if (c[1] == '\0')
                     break;
-                switch (format[++i]) {
+                switch (*++c) {
                     default:
-                        janet_buffer_push_u8(bufp, format[i]);
+                        janet_buffer_push_u8(bufp, *c);
                         break;
                     case 'f':
                         number_to_string_b(bufp, va_arg(args, double));
@@ -535,7 +521,25 @@ const uint8_t *janet_formatc(const char *format, ...) {
             }
         }
     }
+}
 
+/* Helper function for formatting strings. Useful for generating error messages and the like.
+ * Similar to printf, but specialized for operating with janet. */
+const uint8_t *janet_formatc(const char *format, ...) {
+    va_list args;
+    const uint8_t *ret;
+    JanetBuffer buffer;
+    int32_t len = 0;
+
+    /* Calculate length, init buffer and args */
+    while (format[len]) len++;
+    janet_buffer_init(&buffer, len);
+    va_start(args, format);
+
+    /* Run format */
+    janet_formatb(&buffer, format, args);
+
+    /* Iterate length */
     va_end(args);
 
     ret = janet_string(buffer.data, buffer.count);

src/core/typedarray.c

@@ -117,6 +117,7 @@ static const JanetAbstractType ta_buffer_type = {
     NULL,
     ta_buffer_marshal,
     ta_buffer_unmarshal,
+    NULL
 };
 
 static int ta_mark(void *p, size_t s) {
@@ -273,7 +274,8 @@ static const JanetAbstractType ta_view_type = {
     ta_getter,
     ta_setter,
     ta_view_marshal,
-    ta_view_unmarshal
+    ta_view_unmarshal,
+    NULL
 };
 
 JanetTArrayBuffer *janet_tarray_buffer(size_t size) {

src/core/util.c

@@ -293,6 +293,7 @@ static const JanetAbstractType type_wrap = {
     NULL,
     NULL,
     NULL,
+    NULL,
     NULL
 };
 

src/include/janet.h

@@ -833,6 +833,7 @@ struct JanetAbstractType {
     void (*put)(void *data, Janet key, Janet value);
     void (*marshal)(void *p, JanetMarshalContext *ctx);
     void (*unmarshal)(void *p, JanetMarshalContext *ctx);
+    void (*tostring)(void *p, JanetBuffer *buffer);
 };
 
 struct JanetReg {
@@ -1101,6 +1102,7 @@ JANET_API void janet_description_b(JanetBuffer *buffer, Janet x);
 #define janet_cstringv(cstr) janet_wrap_string(janet_cstring(cstr))
 #define janet_stringv(str, len) janet_wrap_string(janet_string((str), (len)))
 JANET_API const uint8_t *janet_formatc(const char *format, ...);
+JANET_API void janet_formatb(JanetBuffer *bufp, const char *format, va_list args);
 
 /* Symbol functions */
 JANET_API const uint8_t *janet_symbol(const uint8_t *str, int32_t len);