ASR -> CPython: Add list method visitors (#2694)

* Add visitors for `append`, `count`, `remove`, `clear` and `insert`

* Tests: Add tests and create references

* Fix codegen considering whether the method has a return value

* Tests: Update test references

* Tests: Update test references pertaining to fix related to `__main__global_stmts`

src/libasr/codegen/asr_to_python.cpp

@@ -636,6 +636,56 @@ class ASRToLpythonVisitor : public ASR::BaseVisitor<ASRToLpythonVisitor>
     void visit_SetConstant(const ASR::SetConstant_t &x) {
         visit_AggregateConstant(x.n_elements, x.m_elements, "{", "}");
     }
+
+    // An aggregate visitor for list methods with 0 or 1 argument
+    void visit_UnaryListMethods(ASR::expr_t* list, std::string method_name,
+                ASR::expr_t* arg=nullptr, bool has_return_value=false) {
+        std::string r = "";
+        visit_expr(*list);
+        r += s;
+        r += "." + method_name + "(";
+        if (arg != nullptr) {
+            visit_expr(*arg);
+            r += s;
+        }
+        r += ")";
+        if (!has_return_value) {
+            r = indent + r + "\n";
+        }
+
+        s = r;
+    }
+
+    void visit_ListAppend(const ASR::ListAppend_t &x) {
+       visit_UnaryListMethods(x.m_a, "append", x.m_ele);
+    }
+
+    void visit_ListCount(const ASR::ListCount_t &x) {
+        visit_UnaryListMethods(x.m_arg, "count", x.m_ele, true);
+    }
+
+    void visit_ListRemove(const ASR::ListRemove_t &x) {
+        visit_UnaryListMethods(x.m_a, "remove", x.m_ele);
+    }
+
+    void visit_ListClear(const ASR::ListClear_t &x) {
+        visit_UnaryListMethods(x.m_a, "clear");
+    }
+
+    void visit_ListInsert(const ASR::ListInsert_t &x) {
+        std::string r = indent;
+        visit_expr(*x.m_a);
+        r += s;
+        r += ".insert(";
+        visit_expr(*x.m_pos);
+        r += s + ", ";
+        visit_expr(*x.m_ele);
+        r += s;
+        r += ")\n";
+
+        s = r;
+    }
+
 };
 
 Result<std::string> asr_to_python(Allocator& al, ASR::TranslationUnit_t &asr,

tests/reference/python-test_list_methods-ceccf6b.json

@@ -0,0 +1,13 @@
+{
+    "basename": "python-test_list_methods-ceccf6b",
+    "cmd": "lpython --no-color --show-python {infile}",
+    "infile": "tests/test_list_methods.py",
+    "infile_hash": "8fe6f0b490e63a1b86d4964ede9d5410d421e0251bd692d36a4b79c6",
+    "outfile": null,
+    "outfile_hash": null,
+    "stdout": "python-test_list_methods-ceccf6b.stdout",
+    "stdout_hash": "888c041c38f4a7c2ea49df884a2caae10cc223b746227de97f9abf25",
+    "stderr": null,
+    "stderr_hash": null,
+    "returncode": 0
+}

tests/reference/python-test_list_methods-ceccf6b.stdout

@@ -0,0 +1,63 @@
+def __main__global_stmts():
+    my_first_list = [1, 2, 3, 4, 5]
+    print(my_first_list)
+    my_first_list.append(4)
+    my_first_list.remove(2)
+    print(my_first_list.count(4))
+    my_first_list.insert(0, 1)
+    my_first_list.clear()
+    my_second_list = [1.200000, 4.300000, 2.800000]
+    print(my_second_list)
+    my_second_list.append(4.300000)
+    my_second_list.remove(2.800000)
+    print(my_second_list.count(4.300000))
+    my_second_list.insert(0, 3.300000)
+    my_second_list.clear()
+    my_third_list = ["hello", "world", "lpython"]
+    print(my_third_list)
+    my_third_list.append("hello")
+    my_third_list.remove("world")
+    print(my_third_list.count("hello"))
+    my_third_list.insert(0, "hi")
+    my_third_list.clear()
+    my_fourth_list = [(1.200000, 4.300000), (2.800000, 3.300000)]
+    print(my_fourth_list)
+    my_fourth_list.append((1.600000, 2.200000))
+    my_fourth_list.remove((1.200000, 4.300000))
+    print(my_fourth_list.count((2.800000, 3.300000)))
+    my_fourth_list.insert(0, (1.000000, 0.000000))
+    my_fourth_list.clear()
+    f()
+def f():
+    my_first_list: list[i32]
+    my_fourth_list: list[tuple[f64, f64]]
+    my_second_list: list[f64]
+    my_third_list: list[str]
+    my_first_list = [1, 2, 3, 4, 5]
+    print(my_first_list)
+    my_first_list.append(4)
+    my_first_list.remove(2)
+    print(my_first_list.count(4))
+    my_first_list.insert(0, 1)
+    my_first_list.clear()
+    my_second_list = [1.200000, 4.300000, 2.800000]
+    print(my_second_list)
+    my_second_list.append(4.300000)
+    my_second_list.remove(2.800000)
+    print(my_second_list.count(4.300000))
+    my_second_list.insert(0, 3.300000)
+    my_second_list.clear()
+    my_third_list = ["hello", "world", "lpython"]
+    print(my_third_list)
+    my_third_list.append("hello")
+    my_third_list.remove("world")
+    print(my_third_list.count("hello"))
+    my_third_list.insert(0, "hi")
+    my_third_list.clear()
+    my_fourth_list = [(1.200000, 4.300000), (2.800000, 3.300000)]
+    print(my_fourth_list)
+    my_fourth_list.append((1.600000, 2.200000))
+    my_fourth_list.remove((1.200000, 4.300000))
+    print(my_fourth_list.count((2.800000, 3.300000)))
+    my_fourth_list.insert(0, (1.000000, 0.000000))
+    my_fourth_list.clear()

tests/test_list_methods.py

@@ -0,0 +1,79 @@
+from lpython import i32, f64
+
+# Global scope
+my_first_list: list[i32] = [1, 2, 3, 4, 5]
+print(my_first_list)
+
+my_first_list.append(4)
+my_first_list.remove(2)
+print(my_first_list.count(4))
+my_first_list.insert(0, 1)
+my_first_list.clear()
+
+my_second_list: list[f64] = [1.2, 4.3, 2.8]
+print(my_second_list)
+
+my_second_list.append(4.3)
+my_second_list.remove(2.8)
+print(my_second_list.count(4.3))
+my_second_list.insert(0, 3.3)
+my_second_list.clear()
+
+my_third_list: list[str] = ["hello", "world", "lpython"]
+print(my_third_list)
+
+my_third_list.append("hello")
+my_third_list.remove("world")
+print(my_third_list.count("hello"))
+my_third_list.insert(0, "hi")
+my_third_list.clear()
+
+my_fourth_list: list[tuple[f64, f64]] = [(1.2, 4.3), (2.8, 3.3)]
+print(my_fourth_list)
+
+my_fourth_list.append((1.6, 2.2))
+my_fourth_list.remove((1.2, 4.3))
+print(my_fourth_list.count((2.8, 3.3)))
+my_fourth_list.insert(0, (1.0, 0.0))
+my_fourth_list.clear()
+
+# Local scope
+def f():
+    my_first_list: list[i32] = [1, 2, 3, 4, 5]
+    print(my_first_list)
+
+    my_first_list.append(4)
+    my_first_list.remove(2)
+    print(my_first_list.count(4))
+    my_first_list.insert(0, 1)
+    my_first_list.clear()
+
+    my_second_list: list[f64] = [1.2, 4.3, 2.8]
+    print(my_second_list)
+
+    my_second_list.append(4.3)
+    my_second_list.remove(2.8)
+    print(my_second_list.count(4.3))
+    my_second_list.insert(0, 3.3)
+    my_second_list.clear()
+
+    my_third_list: list[str] = ["hello", "world", "lpython"]
+    print(my_third_list)
+
+    my_third_list.append("hello")
+    my_third_list.remove("world")
+    print(my_third_list.count("hello"))
+    my_third_list.insert(0, "hi")
+    my_third_list.clear()
+
+    my_fourth_list: list[tuple[f64, f64]] = [(1.2, 4.3), (2.8, 3.3)]
+    print(my_fourth_list)
+
+    my_fourth_list.append((1.6, 2.2))
+    my_fourth_list.remove((1.2, 4.3))
+    print(my_fourth_list.count((2.8, 3.3)))
+    my_fourth_list.insert(0, (1.0, 0.0))
+    my_fourth_list.clear()
+
+
+f()

tests/tests.toml

@@ -55,6 +55,10 @@ asr = true
 filename = "test_aggregate_constants.py"
 python = true
 
+[[test]]
+filename = "test_list_methods.py"
+python = true
+
 [[test]]
 filename = "expr1.py"
 ast = true