14.5 Limitations and Future Plans

We hope you find dgawk useful and enjoyable to work with, but as with any program, especially in its early releases, it still has some limitations. A few which are worth being aware of are:

• At this point, dgawk does not give a detailed explanation of what you did wrong when you type in something it doesn’t like. Rather, it just responds ‘syntax error’. When you do figure out what your mistake was, though, you’ll feel like a real guru.
• If you perused the dump of opcodes in Miscellaneous Commands, (or if you are already familiar with gawk internals), you will realize that much of the internal manipulation of data in gawk, as in many interpreters, is done on a stack. Op_push, Op_pop, etc., are the “bread and butter” of most gawk code. Unfortunately, as of now, dgawk does not allow you to examine the stack’s contents.

  That is, the intermediate results of expression evaluation are on the stack, but cannot be printed. Rather, only variables which are defined in the program can be printed. Of course, a workaround for this is to use more explicit variables at the debugging stage and then change back to obscure, perhaps more optimal code later.

• There is no way to look “inside” the process of compiling regular expressions to see if you got it right. As an awk programmer, you are expected to know what /[^[:alnum:][:blank:]]/ means.
• dgawk is designed to be used by running a program (with all its parameters) on the command line, as described in dgawk Invocation. There is no way (as of now) to attach or “break in” to a running program. This seems reasonable for a language which is used mainly for quickly executing, short programs.
• dgawk only accepts source supplied with the ‘-f’ option.

Look forward to a future release when these and other missing features may be added, and of course feel free to try to add them yourself!