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gawk: Limitations

 
 14.5 Limitations
 ================
 
 We hope you find the 'gawk' debugger useful and enjoyable to work with,
 but as with any program, especially in its early releases, it still has
 some limitations.  A few that it's worth being aware of are:
 
    * At this point, the debugger 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 Debugger
      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', and the like are the "bread and butter" of most 'gawk'
      code.
 
      Unfortunately, as of now, the 'gawk' debugger 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 that 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 the meaning of '/[^[:alnum:][:blank:]]/'.
 
    * The 'gawk' debugger is designed to be used by running a program
      (with all its parameters) on the command line, as described in
      ⇒Debugger Invocation.  There is no way (as of now) to attach
      or "break into" a running program.  This seems reasonable for a
      language that is used mainly for quickly executing, short programs.
 
    * The 'gawk' debugger only accepts source code supplied with the '-f'
      option.
 
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