Address listed flaws in implementation

code/compiler/02/parser.y

@@ -35,10 +35,12 @@ extern yy::parser::symbol_type yylex();
 %type <std::vector<std::string>> lowercaseParams
 %type <std::vector<definition_ptr>> program definitions
 %type <std::vector<branch_ptr>> branches
+%type <std::vector<constructor_ptr>> constructors
 %type <ast_ptr> aAdd aMul case app appBase
-%type <definition_ptr> definition
+%type <definition_ptr> definition defn data 
 %type <branch_ptr> branch
 %type <pattern_ptr> pattern
+%type <constructor_ptr> constructor
 
 %start program
 
@@ -54,6 +56,11 @@ definitions
     ;
 
 definition
+    : defn { $$ = std::move($1); }
+    | data { $$ = std::move($1); }
+    ;
+
+defn
     : DEFN LID lowercaseParams EQUAL OCURLY aAdd CCURLY
         { $$ = definition_ptr(
             new definition_defn(std::move($2), std::move($3), std::move($6))); }
@@ -109,3 +116,20 @@ pattern
     | UID lowercaseParams
         { $$ = pattern_ptr(new pattern_constr(std::move($1), std::move($2))); }
     ;
+
+data
+    : DATA UID EQUAL OCURLY constructors CCURLY
+        { $$ = definition_ptr(new definition_data(std::move($2), std::move($5))); }
+    ;
+
+constructors
+    : constructors COMMA constructor { $$ = std::move($1); $$.push_back(std::move($3)); }
+    | constructor
+        { $$ = std::vector<constructor_ptr>(); $$.push_back(std::move($1)); }
+    ;
+
+constructor
+    : UID lowercaseParams
+        { $$ = constructor_ptr(new constructor(std::move($1), std::move($2))); }
+    ;
+