String concatenation.

c/builtin.c

@@ -22,6 +22,8 @@ static void f_plus(jv input[], jv output[]) {
   if (jv_get_kind(a) == JV_KIND_NUMBER && jv_get_kind(b) == JV_KIND_NUMBER) {
     output[0] = jv_number(jv_number_value(a) + 
                           jv_number_value(b));
+  } else if (jv_get_kind(a) == JV_KIND_STRING && jv_get_kind(b) == JV_KIND_STRING) {
+    output[0] = jv_string_concat(a, b);
   } else if (jv_get_kind(a) == JV_KIND_ARRAY && jv_get_kind(b) == JV_KIND_ARRAY) {
     output[0] = jv_array_concat(a, b);
   } else if (jv_get_kind(a) == JV_KIND_OBJECT && jv_get_kind(b) == JV_KIND_OBJECT) {

c/jv.c

@@ -355,6 +355,7 @@ static jv_complex jvp_string_new(const char* data, uint32_t length) {
   return r;
 }
 
+
 static void jvp_string_free(jv_complex* s) {
   if (jvp_refcnt_dec(s)) {
     jvp_string* str = jvp_string_ptr(s);
@@ -377,6 +378,16 @@ static uint32_t jvp_string_length(jvp_string* s) {
   return s->length_hashed >> 1;
 }
 
+static jv_complex jvp_string_concat(jvp_string* a, jvp_string* b) {
+  uint32_t la = jvp_string_length(a), lb = jvp_string_length(b);
+  jvp_string* s = jvp_string_alloc(la + lb);
+  memcpy(s->data, a->data, la);
+  memcpy(s->data + la, b->data, lb);
+  s->data[la + lb] = 0;
+  jv_complex r = {&s->refcnt, {0,0}};
+  return r;
+}
+
 static const uint32_t HASH_SEED = 0x432A9843;
 
 static uint32_t rotl32 (uint32_t x, int8_t r){
@@ -488,6 +499,16 @@ const char* jv_string_value(jv j) {
   return jvp_string_ptr(&j.val.complex)->data;
 }
 
+jv jv_string_concat(jv a, jv b) {
+  jv j;
+  j.kind = JV_KIND_STRING;
+  j.val.complex = jvp_string_concat(jvp_string_ptr(&a.val.complex),
+                                    jvp_string_ptr(&b.val.complex));
+  jv_free(a);
+  jv_free(b);
+  return j;
+}
+
 jv jv_string_fmt(const char* fmt, ...) {
   int size = 1024;
   while (1) {

c/jv.h

@@ -76,6 +76,7 @@ jv jv_string_sized(const char*, int);
 int jv_string_length(jv);
 uint32_t jv_string_hash(jv);
 const char* jv_string_value(jv);
+jv jv_string_concat(jv, jv);
 jv jv_string_fmt(const char*, ...);
 
 jv jv_object();

c/testdata

@@ -159,6 +159,14 @@ null
 "asdfasdf"
 {"a":1, "b":2, "c":3}
 
+"asdf" + "jkl;" + .
+"some string"
+"asdfjkl;some string"
+
+"\u0000\u0020\u0000" + .
+"\u0000\u0020\u0000"
+"\u0000 \u0000\u0000 \u0000"
+
 #
 # User-defined functions
 # Oh god.