Added str.replace() (#2587)

* added str.replace() string API

* references updated

* Delete kishan.py

* updated references 2

* removed empty string tests

* fix c test

* fixed empty string case

* updated references 3

* TEST: Update reference tests

---------

Co-authored-by: Shaikh Ubaid <shaikhubaid769@gmail.com>

Author: Kishan-Ved

integration_tests/test_str_01.py

@@ -114,6 +114,55 @@ def test_str_split():
     assert res5 == ["123"]
     # assert res6 == [""]
 
+def test_str_replace():
+    x: str = "abc"
+    a: str = "zzaaabracadabra"
+    print(a.replace("a",""))
+    print(a.replace("",""))
+    print(a.replace("a","b"))
+    print(a.replace("e","a")) 
+    print(a.replace("ab","ba"))
+    print(a.replace("c","z"))
+    print(a.replace("zza","yo"))
+    print(a.replace("a","b",0))
+    print(a.replace("a","b",1))
+    print(a.replace("a","b",2))
+    print(a.replace("a","b",2))
+    print(a.replace("a","b",3))
+    print(a.replace("a","b",4))
+    print(a.replace("a","b",5))
+    print(a.replace("a","b",6))
+    print(a.replace("a","b",7))
+    print(a.replace("a","b",8))
+    print(a.replace("a","b",9))
+    print(a.replace("b","k",1))
+    print(a.replace("b","k",2))
+    print(a.replace("zza","yo",2))
+    print(x.replace("", ","))
+    assert a.replace("a","") == "zzbrcdbr"
+    assert a.replace("","") == "zzaaabracadabra"
+    assert a.replace("a","b") == "zzbbbbrbcbdbbrb"
+    assert a.replace("e","a") == "zzaaabracadabra"
+    assert a.replace("ab","ba") == "zzaabaracadbara"
+    assert a.replace("c","z") == "zzaaabrazadabra"
+    assert a.replace("zza","yo") == "yoaabracadabra"
+    assert a.replace("a","b",0) == "zzaaabracadabra"
+    assert a.replace("a","b",1) == "zzbaabracadabra"
+    assert a.replace("a","b",2) == "zzbbabracadabra"
+    assert a.replace("a","b",2) == "zzbbabracadabra"
+    assert a.replace("a","b",3) == "zzbbbbracadabra"
+    assert a.replace("a","b",4) == "zzbbbbrbcadabra"
+    assert a.replace("a","b",5) == "zzbbbbrbcbdabra"
+    assert a.replace("a","b",6) == "zzbbbbrbcbdbbra"
+    assert a.replace("a","b",7) == "zzbbbbrbcbdbbrb"
+    assert a.replace("a","b",8) == "zzbbbbrbcbdbbrb"
+    assert a.replace("a","b",9) == "zzbbbbrbcbdbbrb"
+    assert a.replace("b","k",1) == "zzaaakracadabra"
+    assert a.replace("b","k",2) == "zzaaakracadakra"
+    assert a.replace("zza","yo",2) == "yoaabracadabra"
+    assert x.replace("", ",") == ",a,b,c,"
+
+
 def check():
     f()
     test_str_concat()
@@ -127,5 +176,6 @@ def check():
     test_constant_str_subscript()
     test_str_title()
     test_str_split()
+    test_str_replace()
 
 check()

src/lpython/semantics/python_ast_to_asr.cpp

@@ -6789,6 +6789,41 @@ class BodyVisitor : public CommonVisitor<BodyVisitor> {
             } else {
                 fn_args.push_back(al, str);
             }
+         } else if(attr_name == "replace") {
+            if(!(args.size() == 2 || args.size()==3)) {
+                throw SemanticError("str.replace() takes two or three arguments.", loc);
+            }
+            ASR::expr_t *arg_value = args[0].m_value;
+            ASR::ttype_t *arg_value_type = ASRUtils::expr_type(arg_value);
+            if (!ASRUtils::is_character(*arg_value_type)) {
+                throw SemanticError("str.replace() argument 1 must be str", loc);
+            }
+            arg_value = args[1].m_value;
+            arg_value_type = ASRUtils::expr_type(arg_value);
+            if (!ASRUtils::is_character(*arg_value_type)) {
+                throw SemanticError("str.replace() argument 2 must be str", loc);
+            }
+            fn_call_name = "_lpython_str_replace";
+            ASR::call_arg_t str;
+            str.loc = loc;
+            str.m_value = s_var;
+
+            ASR::call_arg_t value;
+            value.loc = loc;
+            value.m_value = args[0].m_value;
+            fn_args.push_back(al, str);
+            fn_args.push_back(al, value);
+            value.m_value = args[1].m_value;
+            fn_args.push_back(al, value);
+            if(args.size()==3){
+                ASR::expr_t *arg_value = args[2].m_value;
+                ASR::ttype_t *arg_value_type = ASRUtils::expr_type(arg_value);
+                if (!ASRUtils::is_integer(*arg_value_type)) {
+                    throw SemanticError("str.replace() argument 3 must be int", loc);
+                }
+                value.m_value = args[2].m_value;
+                fn_args.push_back(al, value);
+            }
         } else if(attr_name.size() > 2 && attr_name[0] == 'i' && attr_name[1] == 's') {
             /*
                 String Validation Methods i.e all "is" based functions are handled here

src/lpython/semantics/python_comptime_eval.h

@@ -91,6 +91,7 @@ struct PythonIntrinsicProcedures {
             {"_lpython_str_lstrip", {m_builtin, &not_implemented}},
             {"_lpython_str_strip", {m_builtin, &not_implemented}},
             {"_lpython_str_split", {m_builtin, &not_implemented}},
+            {"_lpython_str_replace", {m_builtin, &not_implemented}},
             {"_lpython_str_swapcase", {m_builtin, &not_implemented}},
             {"_lpython_str_startswith", {m_builtin, &not_implemented}},
             {"_lpython_str_endswith", {m_builtin, &not_implemented}},

src/runtime/lpython_builtin.py

@@ -915,6 +915,39 @@ def _lpython_str_split(x: str, sep:str) -> list[str]:
             start += ind + len(sep)
     return res
 
+@overload
+def _lpython_str_replace(x: str, old:str, new:str) -> str:
+    return _lpython_str_replace(x, old, new, len(x))
+    
+
+@overload
+def _lpython_str_replace(x: str, old:str, new:str, count: i32) -> str:
+    if (old == ""):
+        res1: str = ""
+        s: str
+        for s in x:
+            res1 += new + s
+        return res1 + new
+    res: str = ""
+    i: i32 = 0
+    ind: i32 = -1
+    l: i32 = len(new)
+    lo: i32 = len(old)
+    lx: i32 = len(x)
+    c: i32 = 0
+    t: i32 = -1
+
+    while(c<count):
+        t = _lpython_str_find(x[i:lx], old)
+        if(t==-1):
+            break
+        ind = i + t
+        res = res + x[i:ind] + new
+        i = ind + lo
+        c = c + 1
+    res = res + x[i:lx]
+    return res
+
 @overload
 def _lpython_str_swapcase(s: str) -> str:
     res :str = ""

tests/reference/asr-array_01_decl-39cf894.json

@@ -6,7 +6,7 @@
     "outfile": null,
     "outfile_hash": null,
     "stdout": "asr-array_01_decl-39cf894.stdout",
-    "stdout_hash": "7e3c68aa6acba27674e544f894bb141357db82f8840c756af448f5bb",
+    "stdout_hash": "f14010ffcf7d42b89e54c88ebecc7ca51d67b204825e07f4f708875e",
     "stderr": null,
     "stderr_hash": null,
     "returncode": 0