Add A command line parsing procedure

source/Compiler.mod

@@ -1,18 +1,50 @@
 MODULE Compiler;
 
-FROM FIO IMPORT StdIn;
+FROM FIO IMPORT Close, IsNoError, File, OpenToRead, StdErr, StdOut, WriteLine, WriteString;
 FROM SYSTEM IMPORT ADR;
+FROM M2RTS IMPORT HALT, ExitOnHalt;
 
 FROM Lexer IMPORT Lexer, lexer_destroy, lexer_initialize;
 FROM Transpiler IMPORT transpile;
+FROM CommandLineInterface IMPORT PCommandLine, parse_command_line;
 
+VAR
+  command_line: PCommandLine;
+
+PROCEDURE compile_from_stream();
 VAR
   lexer: Lexer;
-
+  source_input: File;
 BEGIN
-  lexer_initialize(ADR(lexer), StdIn);
+  source_input := OpenToRead(command_line^.input);
 
-  transpile(ADR(lexer));
+  IF IsNoError(source_input) = FALSE THEN
+    WriteString(StdErr, 'Fatal error: failed to read the input file "');
+    WriteString(StdErr, command_line^.input);
+    WriteString(StdErr, '".');
+    WriteLine(StdErr);
 
-  lexer_destroy(ADR(lexer))
+    ExitOnHalt(2)
+  END;
+  IF IsNoError(source_input) THEN
+    lexer_initialize(ADR(lexer), source_input);
+
+    transpile(ADR(lexer), StdOut);
+
+    lexer_destroy(ADR(lexer));
+
+    Close(source_input)
+  END
+END compile_from_stream;
+BEGIN
+  ExitOnHalt(0);
+  command_line := parse_command_line();
+
+  IF command_line <> NIL THEN
+    compile_from_stream()
+  END;
+  IF command_line = NIL THEN
+    ExitOnHalt(1)
+  END;
+  HALT()
 END Compiler.