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Release Notes

Migrating from the old prototype

Below we summarize language changes in Spicy compared to the original research prototype. Note that some of the prototype's more advanced functionality has not yet been ported to the new code base; see the corresponding list on GitHub for what's still missing.

Changes:

  • Renamed export linkage to public.
  • Renamed %byteorder property to %byte-order.
  • Renamed &byteorder attribute to &byte-order.
  • Renamed &bitorder attribute to &bit-order.
  • All unit-level properties now need to conclude with a semicolon (e.g., %filter;).
  • Renamed &length attribute to &size.
  • Renamed &until_including attribute to &until-including.
  • Replaced &parse with separate &parse-from (taking a "bytes" instance) and &parse-at (taking a stream iterator) attributes.
  • Attributes no longer accept their arguments in parentheses, it now must <attr>=expr. (Before, both versions were accepted.)
  • uint<N> and int<N> are no longer accepted, use uintN/intN instead (which worked before already as well)
  • list<T> is no longer supported, use vector<T> instead.
  • New syntax for parsing sequences: Use x: int8[5] instead of x: vector<int8> &length=5. For lists of unknown size, use x: int8[]. When parsing sequences sub-units, use: x: Item[]; or, if further arguments/attributes are required, x: (Item(1,2,3))[]. (The latter syntax isn't great, but the old syntax was ambiguous.)
  • New syntax for functions: function f(<params>) [: <result>] instead of <result> f(<params>)
  • Renamed runtime support module from Spicy to spicy (so use import spicy)
  • In units, variables are now initialized to default values by default. Previously, that was (inconsistently) happening only for variables of type sink. To revert to the old behaviour, add "&optional" to the variable.
  • Renamed type double to real.
  • Generally, types don't coerce implicitly to bool anymore except in specific language contexts, such as in statements with boolean conditions.
  • Filters can now be implemented in Spicy itself. The pre-built filter::Base64Decode and filter::Zlib provide the base64 and zlib functionality of the previously built-in filters.
  • {unit,sink}::add_filter are renamed to {unit,sink}::connect_filter.
  • Enums don't coerce to bool anymore, need to manually compare to Undef.
  • Coercion to bool now happens only in certain contexts, like if-conditions (similar to C++).
  • The sink method sequence has been renamed to sequence_number.
  • The effect of the sink method set_initial_sequence_number no longer persists when reconnecting a different unit to a sink.
  • &transient is no longer a supported unit field attribute. The same effect can now be achieved through an anonymous field (also see next point).
  • $$ can now be generally used in hooks to refer to the just parsed value. That's particularly useful inside hooks for anonymous fields, including fields that previously were &transient (see above). Previously, "$$" worked only for container elements in foreach hooks (which still operates the same way).
  • Fields of type real are parsed with &type attribute (e.g., &type=Spicy::RealType::IEEE754_Double). They used to &precision attributes with a different enum type.
  • Assigning to unit fields and variables no longer triggers any hooks. That also means that hooks are generally no longer supported for variables (This is tricky to implement, not clear it's worth the effort.)
  • When importing modules, module names are now case-sensitive.
  • When parsing vectors/lists of integers of a given length, use &count instead of &length.

  • Zeek plugin:

    • Bro::dpd_confirm() has been renamed to zeek::confirm_protocol(). There's also a corresponding zeek::reject_protocol().
    • To auto-export enums to Zeek, they need to be declared public.