Command-Line Arguments

There are five possible command-line arguments:

-t

Suppresses generation of the .tex file.

-o

Suppresses generation of the output files.

-c

Forces output files to overwrite old files of the same name without comparing for equality first.

-v

The verbose flag. Forces output of progress reports.

-n

Forces sequential numbering of scraps (instead of page numbers).

Global flags are declared for each of the arguments. @d Global variable dec... @extern int tex_flag; /* if FALSE, don't emit the .tex file */ extern int output_flag; /* if FALSE, don't emit the output files */ extern int compare_flag; /* if FALSE, overwrite without comparison */ extern int verbose_flag; /* if TRUE, write progress information */ extern int number_flag; /* if TRUE, use a sequential numbering scheme */ @| tex_flag output_flag compare_flag verbose_flag number_flag @

The flags are all initialized for correct default behavior.

@d Global variable def... @int tex_flag = TRUE; int output_flag = TRUE; int compare_flag = TRUE; int verbose_flag = FALSE; int number_flag = FALSE; @

We save the invocation name of the command in a global variable command_name for use in error messages. @d Global variable dec... @extern char *command_name; @| command_name @

@d Global variable def... @char *command_name = NULL; @

The invocation name is conventionally passed in argv[0]. @d Interpret com... @command_name = argv[0]; @

We need to examine the remaining entries in argv, looking for command-line arguments. @d Interpret com... @while (arg < argc) char *s = argv[arg]; if (*s++ == '-') @<Interpret the argument string s@> arg++; else break; @

Several flags can be stacked behind a single minus sign; therefore, we've got to loop through the string, handling them all. @d Interpret the... @ char c = *s++; while (c) switch (c) case 'c': compare_flag = FALSE; break; case 'n': number_flag = TRUE; break; case 'o': output_flag = FALSE; break; case 't': tex_flag = FALSE; break; case 'v': verbose_flag = TRUE; break; default: fprintf(stderr, "command_name); fprintf(stderr, "Usage is: command_name); break; c = *s++; @