From 12cb48af2c1eedec9ddfe4fb09eecc20ccfdaa5f Mon Sep 17 00:00:00 2001
From: gptsarthak <sarthakgpt95@gmail.com>
Date: Thu, 30 Mar 2023 00:01:27 +0530
Subject: [PATCH] Implement list.count() method

---
 src/lpython/semantics/python_ast_to_asr.cpp  | 38 +++++++++++++++++++-
 src/lpython/semantics/python_comptime_eval.h |  2 ++
 src/runtime/lpython_builtin.py               | 11 ++++++
 3 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/src/lpython/semantics/python_ast_to_asr.cpp b/src/lpython/semantics/python_ast_to_asr.cpp
index f71b9341b0..f9d0a7fd2c 100644
--- a/src/lpython/semantics/python_ast_to_asr.cpp
+++ b/src/lpython/semantics/python_ast_to_asr.cpp
@@ -5883,6 +5883,39 @@ class BodyVisitor : public CommonVisitor<BodyVisitor> {
         tmp = ASR::make_StringConstant_t(al, loc, s2c(al, s_var), str_type);
     }
 
+    void handle_list_attributes(ASR::expr_t *s_var,
+                Vec<ASR::call_arg_t> &args, std::string attr_name, const Location &loc) {
+        std::string fn_call_name = "";
+        Vec<ASR::call_arg_t> fn_args;
+        fn_args.reserve(al, 1);
+        if (attr_name == "count" ) {
+            if(args.size() != 1) {
+                throw SemanticError("list.count() 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("list.count() takes one argument of type: integer",
+                        loc);
+            }
+            fn_call_name = "_lpython_list_count";
+            ASR::call_arg_t str;
+            str.loc = loc;
+            str.m_value = s_var;
+            ASR::call_arg_t sub;
+            sub.loc = loc;
+            sub.m_value = args[0].m_value;
+            fn_args.push_back(al, str);
+            fn_args.push_back(al, sub);
+
+        } else {
+            throw SemanticError("List method not implemented: " + attr_name, loc);
+        }
+        ASR::symbol_t *fn_call = resolve_intrinsic_function(loc, fn_call_name);
+        tmp = make_call_helper(al, fn_call, current_scope, fn_args, fn_call_name, loc);
+    }
+
     void visit_Call(const AST::Call_t &x) {
         std::string call_name = "";
         Vec<ASR::call_arg_t> args;
@@ -5930,6 +5963,10 @@ class BodyVisitor : public CommonVisitor<BodyVisitor> {
                                 handle_string_attributes(se, args, at->m_attr, x.base.base.loc);
                                 return;
                             }
+                            if (ASR::is_a<ASR::List_t>(*(ASRUtils::expr_type(se)))) {
+                                handle_list_attributes(se, args, at->m_attr, x.base.base.loc);
+                                return;
+                            }
                             handle_attribute(se, at->m_attr, x.base.base.loc, eles);
                             return;
                         }
@@ -6010,7 +6047,6 @@ class BodyVisitor : public CommonVisitor<BodyVisitor> {
             throw SemanticError("Only Name or Attribute type supported in Call",
                 x.base.base.loc);
         }
-
         ASR::symbol_t *s = current_scope->resolve_symbol(call_name);
         if( s && ASR::is_a<ASR::Module_t>(*s) ) {
             std::string mangled_name = ASRUtils::get_mangled_name(ASR::down_cast<ASR::Module_t>(s), call_name);
diff --git a/src/lpython/semantics/python_comptime_eval.h b/src/lpython/semantics/python_comptime_eval.h
index 0e6e38b85f..99d12da9bf 100644
--- a/src/lpython/semantics/python_comptime_eval.h
+++ b/src/lpython/semantics/python_comptime_eval.h
@@ -68,6 +68,8 @@ struct PythonIntrinsicProcedures {
             {"max" , {m_builtin , &eval_max}},
             {"min" , {m_builtin , &eval_min}},
             {"sum" , {m_builtin , &not_implemented}},
+            // List methods
+            {"_lpython_list_count", {m_builtin, &not_implemented}},
             // The following functions for string methods are not used
             // for evaluation.
             {"_lpython_str_capitalize", {m_builtin, &not_implemented}},
diff --git a/src/runtime/lpython_builtin.py b/src/runtime/lpython_builtin.py
index 1e5449a7ce..5480b9d0d7 100644
--- a/src/runtime/lpython_builtin.py
+++ b/src/runtime/lpython_builtin.py
@@ -727,6 +727,17 @@ def _lpython_str_find(s: str, sub: str) -> i32:
 
     return res
 
+@overload
+def _lpython_list_count(l: list[i32], x: i32) -> i32:
+    count : i32
+    count = 0
+    i : i32
+    i = 0
+    for i in l:
+        if(i == x):
+            count = count + 1
+    return count
+        
 def _lpython_str_rstrip(x: str) -> str:
     ind: i32
     ind = len(x) - 1