New feature: sc shows composers, and c noc shows pieces by composer

README.md

@@ -18,7 +18,7 @@ At the moment, an alpha version is undertaken, with these features:
 - Set an active user (`a number_of_user`)
 - Show the pieces stored in the database (`s`)
 - Mark pieces as mastered for the active user (`m number_of_work`)
-- (planned) Show pieces by composer
+- Show pieces by composer (`sc` shows composers, `c number_of_composer` shows pieces)
 - (planned) Show movements through pieces
 
 ## Requirements

rep_cli.py

@@ -29,6 +29,8 @@ class Session:
         self.resultstring = ''
         if command == 'a':
             self.resultstring += self.set_user(arguments[0])
+        elif command == 'c':
+            self.resultstring += self.show_composers()
         elif command == 'm':
             self.resultstring += self.mark_work_as_mastered(arguments[0])
         elif command == 'n':
@@ -36,6 +38,8 @@ class Session:
             self.resultstring += f'Created new user {arguments[0]} {arguments[1]}.'
         elif command == 's':
             self.resultstring += self.show_works()
+        elif command == 'sc':
+            self.resultstring += self.show_works(restraint=f'comp_id = {arguments[0]}')
         elif command == 'su':
             self.resultstring += self.show_users()
         elif command == 'q':
@@ -53,6 +57,18 @@ class Session:
                       '''
         self.db_agent.execute(sql_command)
 
+    def show_composers(self):
+        sql_command = '''
+                      SELECT id, first_name, name
+                      FROM composer
+                      ORDER BY name
+                      '''
+        result_list = self.db_agent.execute(sql_command).fetchall()
+        fun_resultstring = ''
+        for item in result_list:
+            fun_resultstring += f'{item[0]}: {item[2]}, {item[1]}\n'
+        return fun_resultstring
+
     def show_users(self):
         sql_command = '''
                       SELECT * FROM pianist;
@@ -63,10 +79,11 @@ class Session:
             fun_resultstring += f'{item[0]}: {item[1]} {item[2]}\n'
         return fun_resultstring
 
-    def show_works(self):
+    def show_works(self, restraint='1=1'):
-        sql_command = '''
+        sql_command = f'''
                       SELECT id
                       FROM work
+                      WHERE {restraint} 
                       '''
         list_of_work_ids = self.db_agent.execute(sql_command).fetchall()
         # GET WORKS OUT!
@@ -203,7 +220,7 @@ class work_under_id:
 def parse_user_input(user_in):
     split_user_in = user_in.split()
     command = split_user_in[0]
-    if command in ('a', 'm', 'n', 'q', 's', 'su'):
+    if command in ('a', 'c', 'm', 'n', 'q', 's', 'sc', 'su'):
         arguments = split_user_in[1:]
         return (command, arguments)
     else: