Args.md

Args

Access command-line arguments passed to the program. This module is compiled into the compiler -- just import it directly with no dependency setup.

Available in PIM4 mode (the default). No special flags needed.

Procedures

PROCEDURE ArgCount(): CARDINAL;

Return the total number of command-line arguments, including the program name itself. A program run as ./myapp foo bar has ArgCount() = 3 (the program name plus two arguments).

PROCEDURE GetArg(n: CARDINAL; VAR buf: ARRAY OF CHAR);

Copy argument number n into buf. Arguments are numbered starting from 0:

Index	Content
0	Program name (e.g., "./myapp")
1	First argument
2	Second argument
...	...

The result is NUL-terminated. If the argument is longer than buf can hold, it is truncated. If n is out of range, buf receives an empty string.

Example

MODULE ArgsDemo;
FROM InOut IMPORT WriteString, WriteInt, WriteLn;
FROM Args IMPORT ArgCount, GetArg;

VAR
  arg: ARRAY [0..255] OF CHAR;
  i: CARDINAL;

BEGIN
  WriteString("Program received ");
  WriteInt(INTEGER(ArgCount()), 1);
  WriteString(" argument(s):"); WriteLn;

  FOR i := 0 TO ArgCount() - 1 DO
    GetArg(i, arg);
    WriteString("  argv[");
    WriteInt(INTEGER(i), 1);
    WriteString("] = ");
    WriteString(arg); WriteLn
  END
END ArgsDemo.

Running mx ArgsDemo.mod -o demo && ./demo hello world prints:

Program received 3 argument(s):
  argv[0] = ./demo
  argv[1] = hello
  argv[2] = world