bank.m

:- module bank.                                                                                                                                                                                                   
:- interface.                                                                                                                                                                                                      
:- import_module io.                                                                                                                                                                                               
                                                                                                                                                                                                                   
:- pred main(io::di, io::uo) is det.                                                                                                                                                                               
                                                                                                                                                                                                                   
:- implementation.                                                                                                                                                                                                 
:- import_module int, string, list.                                                                                                                                                                                
                                                                                                                                                                                                                   
/*                                                                                                                                                                                                                 
:- pred fib(int::in, int::out) is det.                                                                                                                                                                             
fib(N, X) :-                                                                                                                                                                                                       
    (   if      N =< 2                                                                                                                                                                                             
        then    X = 1                                                                                                                                                                                              
        else    fib(N - 1, A), fib(N - 2, B), X = A + B                                                                                                                                                            
    ).                                                                                                                                                                                                             
*/                                                                                                                                                                                                                 
                                                                                                                                                                                                                   
:- type bank_account ---> account( name        :: string,                                                                                                                                                          
                                   account_no  :: int,                                                                                                                                                             
                                   funds       :: float  ).                                                                                                                                                        
                                                                                                                                                                                                                   
                                                                                                                                                                                                                   
:- pred get_arguments(io::di, io::uo, string::out) is det.                                                                                                                                                         
get_arguments(!IO, X) :-                                                                                                                                                                                           
    io.read_line_as_string(Result, !IO),                                                                                                                                                                           
    (                                                                                                                                                                                                              
        Result = eof,                                                                                                                                                                                              
        io.format("Goodbye!\n", [], !IO),                                                                                                                                                                          
        X = "null"                                                                                                                                                                                                 
    ;                                                                                                                                                                                                              
        Result = ok(String),                                                                                                                                                                                       
        X = String                                                                                                                                                                                                 
    ;                                                                                                                                                                                                              
        Result = error(ErrorCode),                                                                                                                                                                                 
        io.format("%s\n", [s(io.error_message(ErrorCode))], !IO),                                                                                                                                                  
        X = "null"                                                                                                                                                                                                 
    ).                                                                                                                                                                                                             
                                                                                                                                                                                                                   
main(!IO) :-                                                                                                                                                                                                       
        get_arguments(!IO, X),                                                                                                                                                                                     
        io.format("echo: %s", [s(X)], !IO),                                                                                                                                                                        
        main(!IO).