ASR -> CPython: Add DictConstant visitor (#2693)

* Add `DictConstant` visitor

* Remove check for `Dict`

The function is not required due to ad404f9

* Improve visitor

* Remove stray newline

* Tests: Add tests and update references

src/libasr/codegen/asr_to_python.cpp

@@ -590,6 +590,25 @@ class ASRToLpythonVisitor : public ASR::BaseVisitor<ASRToLpythonVisitor>
         s = r;
     }
 
+    void visit_DictConstant(const ASR::DictConstant_t &x) {
+        LCOMPILERS_ASSERT(x.n_keys == x.n_values);
+        std::string r = "";
+        r += "{";
+        for (size_t i = 0; i < x.n_keys; i++) {
+            visit_expr(*x.m_keys[i]);
+            r += s;
+            r += ": ";
+            visit_expr(*x.m_values[i]);
+            r += s; 
+            if (i < x.n_keys - 1) {
+                r += ", ";
+            }
+        }
+        r += "}";
+
+        s = r;
+    }
+
     // An aggregate visitor for `ListConstant`, `TupleConstant` & `SetConstant`
     void visit_AggregateConstant(size_t n_args, ASR::expr_t** m_args,
             std::string opening_braces, std::string closing_braces) {
@@ -617,7 +636,6 @@ class ASRToLpythonVisitor : public ASR::BaseVisitor<ASRToLpythonVisitor>
     void visit_SetConstant(const ASR::SetConstant_t &x) {
         visit_AggregateConstant(x.n_elements, x.m_elements, "{", "}");
     }
-
 };
 
 Result<std::string> asr_to_python(Allocator& al, ASR::TranslationUnit_t &asr,

tests/reference/python-test_aggregate_constants-26c89d6.json

@@ -2,11 +2,11 @@
     "basename": "python-test_aggregate_constants-26c89d6",
     "cmd": "lpython --no-color --show-python {infile}",
     "infile": "tests/test_aggregate_constants.py",
-    "infile_hash": "e4f25c9787536c0ecc60a1d53b4bca5f250e2a4f3646b45565867e86",
+    "infile_hash": "6e225037304a9a1222b4c356b8cd1ffc5ed4a58bb7d6916c242c7b53",
     "outfile": null,
     "outfile_hash": null,
     "stdout": "python-test_aggregate_constants-26c89d6.stdout",
-    "stdout_hash": "813b11b4ee92df0eebccb3031a1b73355957795a72b487115093c3ce",
+    "stdout_hash": "3d5fa791404534643f6f2a096b2bc1561cf6c03a78d060b79df4f17b",
     "stderr": null,
     "stderr_hash": null,
     "returncode": 0

tests/reference/python-test_aggregate_constants-26c89d6.stdout

@@ -13,6 +13,12 @@ def __main__global_init():
     my_second_set = {1.100000, 2.500000, 6.800000}
     my_third_set = {"a", "b", "a", "c"}
     my_fourth_set = {(1, "a"), (2, "b"), (3, "c")}
+    my_first_dict = {"a": 1, "b": 2, "c": 3}
+    my_second_dict = {1: 1.330000, 2: 2.330000, 3: 3.330000}
+    my_third_dict = {"a": "A", "b": "B", "c": "C"}
+    my_fourth_dict = {1: (1.200000, 4.500000), 2: (3.600000, 9.200000)}
+    my_fifth_dict = {"list1": [1, 2, 3], "list2": [4, 5, 6]}
+    my_sixth_dict = {"set1": {1, 2, 1}, "set2": {4, 1, 2}}
 def __main__global_stmts():
     print(my_first_list)
     print(my_second_list)
@@ -28,19 +34,31 @@ def __main__global_stmts():
     print(my_second_set)
     print(my_third_set)
     print(my_fourth_set)
+    print(my_first_dict)
+    print(my_second_dict)
+    print(my_third_dict)
+    print(my_fourth_dict)
+    print(my_fifth_dict)
+    print(my_sixth_dict)
     fn()
 def fn():
+    my_fifth_dict: dict[str, list[i32]]
     my_fifth_list: list[set[str]]
+    my_first_dict: dict[str, i32]
     my_first_list: list[i32]
     my_first_set: set[i32]
     my_first_tuple: tuple[i32, str, f64]
+    my_fourth_dict: dict[i32, tuple[f64, f64]]
     my_fourth_list: list[list[f64]]
     my_fourth_set: set[tuple[i32, str]]
     my_fourth_tuple: tuple[set[str], str]
+    my_second_dict: dict[i32, f64]
     my_second_list: list[str]
     my_second_set: set[f64]
     my_second_tuple: tuple[tuple[i32, str], str]
+    my_sixth_dict: dict[str, set[i32]]
     my_sixth_list: list[tuple[i32, str]]
+    my_third_dict: dict[str, str]
     my_third_list: list[list[i32]]
     my_third_set: set[str]
     my_third_tuple: tuple[list[str], str]
@@ -72,3 +90,15 @@ def fn():
     print(my_third_set)
     my_fourth_set = {(1, "a"), (2, "b"), (3, "c")}
     print(my_fourth_set)
+    my_first_dict = {"a": 1, "b": 2, "c": 3}
+    print(my_first_dict)
+    my_second_dict = {1: 1.330000, 2: 2.330000, 3: 3.330000}
+    print(my_second_dict)
+    my_third_dict = {"a": "A", "b": "B", "c": "C"}
+    print(my_third_dict)
+    my_fourth_dict = {1: (1.200000, 4.500000), 2: (3.600000, 9.200000)}
+    print(my_fourth_dict)
+    my_fifth_dict = {"list1": [1, 2, 3], "list2": [4, 5, 6]}
+    print(my_fifth_dict)
+    my_sixth_dict = {"set1": {1, 2, 1}, "set2": {4, 1, 2}}
+    print(my_sixth_dict)

tests/test_aggregate_constants.py

@@ -47,6 +47,25 @@
 my_fourth_set: set[tuple[i32, str]] = {(1, "a"), (2, "b"), (3, "c")}
 print(my_fourth_set)
 
+# Dictionary
+my_first_dict: dict[str, i32] = {"a": 1, "b": 2, "c": 3}
+print(my_first_dict)
+
+my_second_dict: dict[i32, f64] = {1: 1.33, 2: 2.33, 3: 3.33}
+print(my_second_dict)
+
+my_third_dict: dict[str, str] = {"a": "A", "b": "B", "c": "C"}
+print(my_third_dict)
+
+my_fourth_dict: dict[i32, tuple[f64, f64]] = {1: (1.2, 4.5), 2: (3.6, 9.2)}
+print(my_fourth_dict)
+
+my_fifth_dict: dict[str, list[i32]] = {"list1": [1, 2, 3], "list2": [4, 5, 6]}
+print(my_fifth_dict)
+
+my_sixth_dict: dict[str, set[i32]] = {"set1": {1, 2, 1}, "set2": {4, 1, 2}}
+print(my_sixth_dict)
+
 # Test codegen for local scope
 def fn():
     # List
@@ -94,4 +113,23 @@ def fn():
     my_fourth_set: set[tuple[i32, str]] = {(1, "a"), (2, "b"), (3, "c")}
     print(my_fourth_set)
 
+    # Dictionary
+    my_first_dict: dict[str, i32] = {"a": 1, "b": 2, "c": 3}
+    print(my_first_dict)
+
+    my_second_dict: dict[i32, f64] = {1: 1.33, 2: 2.33, 3: 3.33}
+    print(my_second_dict)
+
+    my_third_dict: dict[str, str] = {"a": "A", "b": "B", "c": "C"}
+    print(my_third_dict)
+
+    my_fourth_dict: dict[i32, tuple[f64, f64]] = {1: (1.2, 4.5), 2: (3.6, 9.2)}
+    print(my_fourth_dict)
+
+    my_fifth_dict: dict[str, list[i32]] = {"list1": [1, 2, 3], "list2": [4, 5, 6]}
+    print(my_fifth_dict)
+
+    my_sixth_dict: dict[str, set[i32]] = {"set1": {1, 2, 1}, "set2": {4, 1, 2}}
+    print(my_sixth_dict)
+
 fn()