String attribute methods

integration_tests/test_str_attributes.py

@@ -497,6 +497,17 @@ def expandtabs():
     assert s.expandtabs(0) == "testtest"
     assert s.expandtabs(-5) == "testtest"
 
+def zfill():
+    s1: str = "Teststr"
+    s2: str = "+12T8tr"
+    s3: str = "-!@)21"
+    assert s1.zfill(4) == "Teststr"
+    assert s1.zfill(-3) == "Teststr"
+    assert s1.zfill(10) == "000Teststr"
+
+    assert s2.zfill(9) == "+0012T8tr"
+    assert s3.zfill(11) == "-00000!@)21"
+
 def check():
     capitalize()
     lower()
@@ -519,6 +530,7 @@ def check():
     is_numeric()
     center()
     expandtabs()
+    zfill()
 
 
 check()

src/lpython/semantics/python_ast_to_asr.cpp

@@ -7598,6 +7598,25 @@ class BodyVisitor : public CommonVisitor<BodyVisitor> {
                 value.m_value = args[0].m_value;
                 fn_args.push_back(al, value);
             }
+        } else if (attr_name == "zfill") {
+            if (args.size() != 1) {
+                throw SemanticError("str.zfill() takes one argument", loc);
+            }
+            ASR::expr_t *arg_sub = args[0].m_value;
+            ASR::ttype_t *arg_sub_type = ASRUtils::expr_type(arg_sub);
+            if (!ASRUtils::is_integer(*arg_sub_type)) {
+                throw SemanticError("str.zfill() argument must be integer", loc);
+            }
+            fn_call_name = "_lpython_str_zfill";
+            ASR::call_arg_t str;
+            str.loc = loc;
+            str.m_value = s_var;
+
+            ASR::call_arg_t width;
+            width.loc = loc;
+            width.m_value = args[0].m_value;
+            fn_args.push_back(al, str);
+            fn_args.push_back(al, width);
         } 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

@@ -77,32 +77,33 @@ struct PythonIntrinsicProcedures {
             // The following functions for string methods are not used
             // for evaluation.
             {"_lpython_str_capitalize", {m_builtin, &not_implemented}},
+            {"_lpython_str_center", {m_builtin, &not_implemented}},
             {"_lpython_str_count", {m_builtin, &not_implemented}},
-            {"_lpython_str_lower", {m_builtin, &not_implemented}},
-            {"_lpython_str_upper", {m_builtin, &not_implemented}},
-            {"_lpython_str_join", {m_builtin, &not_implemented}},
+            {"_lpython_str_endswith", {m_builtin, &not_implemented}},
+            {"_lpython_str_expandtabs", {m_builtin, &not_implemented}},
             {"_lpython_str_find", {m_builtin, &not_implemented}},
-            {"_lpython_str_isalpha", {m_builtin, &not_implemented}},
             {"_lpython_str_isalnum", {m_builtin, &not_implemented}},
+            {"_lpython_str_isalpha", {m_builtin, &not_implemented}},
+            {"_lpython_str_isascii", {m_builtin, &not_implemented}},
+            {"_lpython_str_isdecimal", {m_builtin, &not_implemented}},
+            {"_lpython_str_islower", {m_builtin, &not_implemented}},
             {"_lpython_str_isnumeric", {m_builtin, &not_implemented}},
-            {"_lpython_str_title", {m_builtin, &not_implemented}},
+            {"_lpython_str_isspace", {m_builtin, &not_implemented}},
             {"_lpython_str_istitle", {m_builtin, &not_implemented}},
-            {"_lpython_str_rstrip", {m_builtin, &not_implemented}},
+            {"_lpython_str_isupper", {m_builtin, &not_implemented}},
+            {"_lpython_str_join", {m_builtin, &not_implemented}},
+            {"_lpython_str_lower", {m_builtin, &not_implemented}},
             {"_lpython_str_lstrip", {m_builtin, &not_implemented}},
-            {"_lpython_str_strip", {m_builtin, &not_implemented}},
-            {"_lpython_str_split", {m_builtin, &not_implemented}},
+            {"_lpython_str_partition", {m_builtin, &not_implemented}},
             {"_lpython_str_replace", {m_builtin, &not_implemented}},
-            {"_lpython_str_swapcase", {m_builtin, &not_implemented}},
+            {"_lpython_str_rstrip", {m_builtin, &not_implemented}},
+            {"_lpython_str_split", {m_builtin, &not_implemented}},
             {"_lpython_str_startswith", {m_builtin, &not_implemented}},
-            {"_lpython_str_endswith", {m_builtin, &not_implemented}},
-            {"_lpython_str_partition", {m_builtin, &not_implemented}},
-            {"_lpython_str_islower", {m_builtin, &not_implemented}},
-            {"_lpython_str_isupper", {m_builtin, &not_implemented}},
-            {"_lpython_str_isdecimal", {m_builtin, &not_implemented}},
-            {"_lpython_str_isascii", {m_builtin, &not_implemented}},
-            {"_lpython_str_isspace", {m_builtin, &not_implemented}},
-            {"_lpython_str_center", {m_builtin, &not_implemented}},
-            {"_lpython_str_expandtabs", {m_builtin, &not_implemented}}
+            {"_lpython_str_strip", {m_builtin, &not_implemented}},
+            {"_lpython_str_swapcase", {m_builtin, &not_implemented}},
+            {"_lpython_str_title", {m_builtin, &not_implemented}},
+            {"_lpython_str_upper", {m_builtin, &not_implemented}},
+            {"_lpython_str_zfill", {m_builtin, &not_implemented}}
         };
     }
 

src/runtime/lpython_builtin.py

@@ -1,5 +1,6 @@
-from lpython import (i8, i16, i32, i64, f32, f64, c32, c64, overload, u8,
-                     u16, u32, u64)
+from lpython import (c32, c64, f32, f64, i8, i16, i32, i64, overload, u8, u16,
+                     u32, u64)
+
 #from sys import exit
 
 #: abs() as a generic procedure.
@@ -1135,6 +1136,19 @@ def _lpython_str_expandtabs(s: str, tabsize: i32) -> str:
 def _lpython_str_expandtabs(s: str) -> str:
     return _lpython_str_expandtabs(s, 8)
 
+def _lpython_str_zfill(s: str, width: i32) -> str:
+    if (width <= len(s) ):
+        return s
+    ret: str 
+    ret = "0"*(width-len(s))
+
+    if (s[0] == '+' or s[0] == '-'):
+        ret = s[0] + ret + s[1:]
+    else:
+        ret = ret + s
+
+    return ret
+
 def list(s: str) -> list[str]:
     l: list[str] = []
     i: i32

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": "3a65f3ea0a230ad60dcabd62518f2ee3d52a8aa788fc1f7d3835ad72",
+    "stdout_hash": "b4be50651f899e04a031b4dfd46d34206ad554a8dbfd7699a1076f03",
     "stderr": null,
     "stderr_hash": null,
     "returncode": 0