Merge pull request lcompilers#2342 from SudhanshuJoshi09/str-count

Implemented Str.Count() method

integration_tests/CMakeLists.txt

@@ -519,6 +519,7 @@ RUN(NAME test_str_01         LABELS cpython llvm c)
 RUN(NAME test_str_02         LABELS cpython llvm c)
 RUN(NAME test_str_03         LABELS cpython llvm c)
 RUN(NAME test_str_04         LABELS cpython llvm c wasm)
+RUN(NAME test_str_05         LABELS cpython llvm c)
 RUN(NAME test_list_01        LABELS cpython llvm c)
 RUN(NAME test_list_02        LABELS cpython llvm c)
 RUN(NAME test_list_03        LABELS cpython llvm c NOFAST)

integration_tests/test_str_05.py

@@ -0,0 +1,12 @@
+def main0():
+    x: str
+    x = "Hello, World"
+    y: str
+    y = "o"
+    assert x.count(y) == 2
+    y = ""
+    assert x.count(y) == len(x) + 1
+    y = "Hello,"
+    assert x.count(y) == 1
+
+main0()

src/lpython/semantics/python_ast_to_asr.cpp

@@ -6791,6 +6791,28 @@ class BodyVisitor : public CommonVisitor<BodyVisitor> {
                 [&](const std::string &msg, const Location &loc) {
                 throw SemanticError(msg, loc); });
             return;
+        } else if(attr_name == "count") {
+            if(args.size() != 1) {
+                throw SemanticError("str.count() takes one argument for now.", 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.count() takes one argument of type: str", loc);
+            }
+
+            fn_call_name = "_lpython_str_count";
+            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;
+
+            // Push string and substring argument on top of Vector (or Function Arguments Stack basically)
+            fn_args.push_back(al, str);
+            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

@@ -77,6 +77,7 @@ struct PythonIntrinsicProcedures {
             // The following functions for string methods are not used
             // for evaluation.
             {"_lpython_str_capitalize", {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_find", {m_builtin, &not_implemented}},

src/runtime/lpython_builtin.py

@@ -722,6 +722,23 @@ def _lpython_str_capitalize(x: str) -> str:
     res = chr(val) + res[1:]
     return res
 
+
+@overload
+def _lpython_str_count(x: str, y: str) -> i32:
+    if(len(y) == 0): return len(x) + 1
+
+    count: i32 = 0
+    curr_char: str
+    i: i32
+
+    for i in range(len(x)):
+        curr_char = x[i]
+        if curr_char == y[0]:
+            count += i32(x[i:i+len(y)] == y)
+
+    return count
+
+
 @overload
 def _lpython_str_lower(x: 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": "b0dc16e057dc08b7ec8adac23b2d98fa29d536fca17934c2689425d8",
+    "stdout_hash": "960bc68922ceaabf957cbdc2cfc76c1f4a4758856072d6be3ae9ed18",
     "stderr": null,
     "stderr_hash": null,
     "returncode": 0