Handle Class Constructor with arguments using __init__ method (#2775)

Author: tanay-man

integration_tests/CMakeLists.txt

@@ -834,6 +834,7 @@ RUN(NAME lambda_01         LABELS cpython llvm llvm_jit)
 
 RUN(NAME c_mangling        LABELS cpython llvm llvm_jit c)
 RUN(NAME class_01          LABELS cpython llvm llvm_jit)
+RUN(NAME class_02          LABELS cpython llvm llvm_jit)
 
 # callback_04 is to test emulation. So just run with cpython
 RUN(NAME callback_04       IMPORT_PATH .. LABELS cpython)

integration_tests/class_02.py

@@ -0,0 +1,44 @@
+from lpython import i32
+class Character:
+    def __init__(self:"Character", name:str, health:i32, attack_power:i32):
+        self.name :str = name
+        self.health :i32 = health
+        self.attack_power : i32 = attack_power
+        self.is_immortal : bool = False
+    
+    def attack(self:"Character", other:"Character") -> str:
+        other.health -= self.attack_power
+        return self.name+" attacks "+ other.name+" for "+str(self.attack_power)+" damage."
+
+    def is_alive(self:"Character")->bool:
+        if self.is_immortal:
+            return True
+        else:
+            return self.health > 0
+
+def main():
+    hero : Character = Character("Hero", 10, 20)
+    monster : Character = Character("Monster", 50, 15)
+    print(hero.attack(monster))
+    print(monster.health)  
+    assert monster.health == 30
+    print(monster.is_alive())  
+    assert monster.is_alive() == True
+    print("Hero gains temporary immortality")
+    hero.is_immortal = True
+    print(monster.attack(hero))
+    print(hero.health)
+    assert hero. health == -5
+    print(hero.is_alive())
+    assert hero.is_alive() == True
+    print("Hero's immortality runs out")
+    hero.is_immortal = False
+    print(hero.is_alive())
+    assert hero.is_alive() == False
+    print("Restarting")
+    hero = Character("Hero", 10, 20)
+    print(hero.is_alive())
+    assert hero.is_alive() == True
+
+main()
+ 

src/libasr/codegen/asr_to_llvm.cpp

@@ -3087,6 +3087,30 @@ class ASRToLLVMVisitor : public ASR::BaseVisitor<ASRToLLVMVisitor>
         }
     }
 
+    void instantiate_methods(const ASR::Struct_t &x) {
+        SymbolTable *current_scope_copy = current_scope;
+        current_scope = x.m_symtab;
+        for ( auto &item : x.m_symtab->get_scope() ) {
+            if ( is_a<ASR::Function_t>(*item.second) ) {
+                ASR::Function_t *v = down_cast<ASR::Function_t>(item.second);
+                instantiate_function(*v);
+            }
+        }
+        current_scope = current_scope_copy;
+    }
+
+    void visit_methods (const ASR::Struct_t &x) {
+        SymbolTable *current_scope_copy = current_scope;
+        current_scope = x.m_symtab;
+        for ( auto &item : x.m_symtab->get_scope() ) {
+            if ( is_a<ASR::Function_t>(*item.second) ) {
+                ASR::Function_t *v = down_cast<ASR::Function_t>(item.second);
+                visit_Function(*v);
+            }
+        }
+        current_scope = current_scope_copy;
+    }
+
     void start_module_init_function_prototype(const ASR::Module_t &x) {
         uint32_t h = get_hash((ASR::asr_t*)&x);
         llvm::FunctionType *function_type = llvm::FunctionType::get(
@@ -3128,6 +3152,9 @@ class ASRToLLVMVisitor : public ASR::BaseVisitor<ASRToLLVMVisitor>
             } else if (is_a<ASR::EnumType_t>(*item.second)) {
                 ASR::EnumType_t *et = down_cast<ASR::EnumType_t>(item.second);
                 visit_EnumType(*et);
+            } else if (is_a<ASR::Struct_t>(*item.second)) {
+                ASR::Struct_t *st = down_cast<ASR::Struct_t>(item.second);
+                instantiate_methods(*st);
             }
         }
         finish_module_init_function_prototype(x);
@@ -4179,6 +4206,9 @@ class ASRToLLVMVisitor : public ASR::BaseVisitor<ASRToLLVMVisitor>
             if (is_a<ASR::Function_t>(*item.second)) {
                 ASR::Function_t *s = ASR::down_cast<ASR::Function_t>(item.second);
                 visit_Function(*s);
+            } else if ( is_a<ASR::Struct_t>(*item.second) ) {
+                ASR::Struct_t *st = down_cast<ASR::Struct_t>(item.second);
+                visit_methods(*st); 
             }
         }
     }