Basically, a Tokay program is made of

  • Items
  • Sequences
  • Blocks

All these belong together and depend on each other in some way.

The following program demonstrates the usage of items, sequences and blocks in action:

{ # A block...
    # ... is made of sequences
    'Hello' _ Name \
        count_hello++   # ... which are made of items (4 items here).

    'Goodbye' _ {  # an item of a sequence can be a block again
        'Max'  count_bye_max++  # ... which contains other sequences...
        Name   count_bye++      # ... made of items again.

    {}  # a sequence with an empty block as its item

This program is a little parser, which looks for greetings in some input.

  • The occurence of e.g. Hello Jan and Hello Max causes the variablecount_hello to be incremented
  • The occurence of e.g. Goodbye Jan increments the counter count_bye, but
  • An occurence of Goodbye Max, which is a special case here, counts on count_bye_max.

If you are familiar with the AWK programming language, you might see some similarities to the PATTERN { action }-syntax here.

In Tokay, PATTERN can be any sequence of items that need to match before, and { action } can hold further PATTERN { action }-components.