naively implement nqp::replace

lib/MAST/Ops.nqp

@@ -544,7 +544,8 @@ BEGIN {
     1283,
     1286,
     1288,
-    1291);
+    1291,
+    1293);
     MAST::Ops.WHO<@counts> := nqp::list_i(0,
     2,
     2,
@@ -1086,7 +1087,8 @@ BEGIN {
     3,
     2,
     3,
-    2);
+    2,
+    5);
     MAST::Ops.WHO<@values> := nqp::list_i(10,
     8,
     18,
@@ -2379,7 +2381,12 @@ BEGIN {
     65,
     33,
     65,
-    65);
+    65,
+    58,
+    57,
+    33,
+    33,
+    57);
     MAST::Ops.WHO<%codes> := nqp::hash('no_op', 0,
     'const_i8', 1,
     'const_i16', 2,
@@ -2921,7 +2928,8 @@ BEGIN {
     'say_fhs', 538,
     'capturenamedshash', 539,
     'read_fhb', 540,
-    'write_fhb', 541);
+    'write_fhb', 541,
+    'replace', 542);
     MAST::Ops.WHO<@names> := nqp::list('no_op',
     'const_i8',
     'const_i16',
@@ -3463,5 +3471,6 @@ BEGIN {
     'say_fhs',
     'capturenamedshash',
     'read_fhb',
-    'write_fhb');
+    'write_fhb',
+    'replace');
 }

src/core/interp.c

@@ -1389,11 +1389,11 @@ void MVM_interp_run(MVMThreadContext *tc, void (*initial_invoke)(MVMThreadContex
                     GET_REG(cur_op, 2).s, GET_REG(cur_op, 4).o);
                 cur_op += 6;
                 goto NEXT;
-            /*OP(replace):
+            OP(replace):
                 GET_REG(cur_op, 0).s = MVM_string_replace(tc,
-                    GET_REG(cur_op, 2).s, GET_REG(cur_op, 4).s, GET_REG(cur_op, 6).s);
-                cur_op += 8;
-                goto NEXT;*/
+                    GET_REG(cur_op, 2).s, GET_REG(cur_op, 4).i64, GET_REG(cur_op, 6).i64, GET_REG(cur_op, 8).s);
+                cur_op += 10;
+                goto NEXT;
             OP(getcpbyname):
                 GET_REG(cur_op, 0).i64 = MVM_unicode_lookup_by_name(tc,
                     GET_REG(cur_op, 2).s);

src/core/oplabels.h

@@ -543,7 +543,7 @@ static const void * const LABELS[] = {
     &&OP_capturenamedshash,
     &&OP_read_fhb,
     &&OP_write_fhb,
-    NULL,
+    &&OP_replace,
     NULL,
     NULL,
     NULL,

src/core/oplist

@@ -571,3 +571,4 @@ say_fhs             w(int64) r(obj) r(str)
 capturenamedshash   w(obj) r(obj)
 read_fhb            r(obj) r(obj) r(int64)
 write_fhb           r(obj) r(obj)
+replace             w(str) r(str) r(int64) r(int64) r(str)

src/core/ops.c

@@ -3800,9 +3800,16 @@ static MVMOpInfo MVM_op_infos[] = {
         2,
         { MVM_operand_read_reg | MVM_operand_obj, MVM_operand_read_reg | MVM_operand_obj }
     },
+    {
+        MVM_OP_replace,
+        "replace",
+        "  ",
+        5,
+        { MVM_operand_write_reg | MVM_operand_str, MVM_operand_read_reg | MVM_operand_str, MVM_operand_read_reg | MVM_operand_int64, MVM_operand_read_reg | MVM_operand_int64, MVM_operand_read_reg | MVM_operand_str }
+    },
 };
 
-static unsigned short MVM_op_counts = 542;
+static unsigned short MVM_op_counts = 543;
 
 MVMOpInfo * MVM_op_get_op(unsigned short op) {
     if (op >= MVM_op_counts)

src/core/ops.h

@@ -543,6 +543,7 @@
 #define MVM_OP_capturenamedshash 539
 #define MVM_OP_read_fhb 540
 #define MVM_OP_write_fhb 541
+#define MVM_OP_replace 542
 
 #define MVM_OP_EXT_BASE 1024
 #define MVM_OP_EXT_CU_LIMIT 1024

src/strings/ops.c

@@ -401,6 +401,25 @@ MVMString * MVM_string_substring(MVMThreadContext *tc, MVMString *a, MVMint64 of
     return result;
 }
 
+MVMString * MVM_string_replace(MVMThreadContext *tc, MVMString *original, MVMint64 start, MVMint64 count, MVMString *replacement) {
+    /* XXX this could probably be done more efficiently directly. */
+    MVMString *first_part;
+    MVMString *rest_part;
+    MVMString *result;
+
+    MVM_gc_root_temp_push(tc, (MVMCollectable **)&replacement);
+    first_part = MVM_string_substring(tc, original, 0, start);
+    MVM_gc_root_temp_push(tc, (MVMCollectable **)&first_part);
+
+    rest_part  = MVM_string_substring(tc, original, start + count, -1);
+    rest_part  = MVM_string_concatenate(tc, replacement, rest_part);
+    result     = MVM_string_concatenate(tc, first_part, rest_part);
+
+    MVM_gc_root_temp_pop_n(tc, 2);
+
+    return result;
+}
+
 /* Append one string to another. */
 /* XXX inline parent's strands if it's a rope too? */
 MVMString * MVM_string_concatenate(MVMThreadContext *tc, MVMString *a, MVMString *b) {

src/strings/ops.h

@@ -67,6 +67,7 @@ MVMint64 MVM_string_index_from_end(MVMThreadContext *tc, MVMString *haystack, MV
 MVMString * MVM_string_concatenate(MVMThreadContext *tc, MVMString *a, MVMString *b);
 MVMString * MVM_string_repeat(MVMThreadContext *tc, MVMString *a, MVMint64 count);
 MVMString * MVM_string_substring(MVMThreadContext *tc, MVMString *a, MVMint64 start, MVMint64 length);
+MVMString * MVM_string_replace(MVMThreadContext *tc, MVMString *a, MVMint64 start, MVMint64 length, MVMString *replacement);
 void MVM_string_say(MVMThreadContext *tc, MVMString *a);
 void MVM_string_print(MVMThreadContext *tc, MVMString *a);
 MVMint64 MVM_string_equal_at(MVMThreadContext *tc, MVMString *a, MVMString *b, MVMint64 offset);