intern ascii literals

include/pocketpy/interpreter/vm.h

@@ -27,6 +27,8 @@ typedef struct VM {
 
     py_Callbacks callbacks;
 
+    py_TValue ascii_literals[128+1];
+
     py_TValue last_retval;
     py_TValue curr_exception;
     volatile bool is_signal_interrupted;

src/interpreter/vm.c

@@ -83,6 +83,12 @@ void VM__ctor(VM* self) {
     ValueStack__ctor(&self->stack);
 
     /* Init Builtin Types */
+    for(int i = 0; i < 128; i++) {
+        char* p = py_newstrn(&self->ascii_literals[i], 1);
+        *p = i;
+    }
+    py_newstrn(&self->ascii_literals[128], 0);
+
     // 0: unused
     void* placeholder = TypeList__emplace(&self->types);
     memset(placeholder, 0, sizeof(py_TypeInfo));
@@ -640,6 +646,10 @@ void ManagedHeap__mark(ManagedHeap* self) {
     for(py_TValue* p = vm->stack.begin; p != vm->stack.end; p++) {
         pk__mark_value(p);
     }
+    // mark ascii literals
+    for(int i = 0; i < c11__count_array(vm->ascii_literals); i++) {
+        pk__mark_value(&vm->ascii_literals[i]);
+    }
     // mark modules
     ModuleDict__apply_mark(&vm->modules, mark_object);
     // mark types

src/public/modules.c

@@ -456,8 +456,7 @@ static bool builtins_chr(int argc, py_Ref argv) {
     PY_CHECK_ARG_TYPE(0, tp_int);
     py_i64 val = py_toint(py_arg(0));
     if(val < 0 || val > 128) { return ValueError("chr() arg not in range(128)"); }
-    char* data = py_newstrn(py_retval(), 1);
+    py_assign(py_retval(), &pk_current_vm->ascii_literals[val]);
-    data[0] = (char)val;
     return true;
 }
 

src/public/py_str.c

@@ -21,6 +21,17 @@ char* py_newstrn(py_Ref out, int size) {
 }
 
 void py_newstrv(py_OutRef out, c11_sv sv) {
+    if(sv.size == 0) {
+        *out = pk_current_vm->ascii_literals[128];
+        return;
+    }
+    if(sv.size == 1) {
+        int c = sv.data[0];
+        if(c >= 0 && c < 128) {
+            *out = pk_current_vm->ascii_literals[c];
+            return;
+        }
+    }
     char* data = py_newstrn(out, sv.size);
     memcpy(data, sv.data, sv.size);
 }

tests/04_str.py

@@ -190,6 +190,8 @@ assert (1 != '1') is True
 assert (1 == '1') is False
 assert 1 == 1.0
 
+assert chr(97) is 'a'
+
 exit()
 
 # test format()