3. Frequently Asked Questions

3.1. Spicy Language

Are Spicy’s global variables really global?

Indeed, they are. Changes to global variables become visible to all Spicy code; their values are not associated with specific connections or other dynamic state. If they are public, they can even be accessed from other, unrelated modules as well. This all means that globals often won’t be the right tool for the job; it’s rare that a parser needs truly global state. Take a look at Contexts for a different mechanism tying state to the current connection, which is a much more common requirement.

What do the numbers in foo.spicy:37:1 or foo.spicy:37:1-42:19 in messages mean?

These are source locations or source ranges. You might encounter them in e.g., error messages from the Spicy compiler or in errors when parsing fails.

In this case foo.spicy:37:1 is a source location, in particular it refers to line 37, character 1 in the file foo.spicy; foo.spicy:37:1-42:19 is a source range in the file foo.spicy starting in line 37, character 1 and ending in line 42, character 19 in the same file.

I expect some code to throw an exception, but this does not always seem to happen. What is going on here?

Spicy performs checks for correct usage, e.g., undefined integer operations like 1/0 or MAX_INT + 1, or dereferencing an invalid iterator. At the same time, however, the Spicy compiler may perform some optimizations removing unneeded code, i.e., code without “useful” side effects. In the case of above examples a statement 1/0; could be removed while a statement like print 1/0; would not since it has a side effect (visible output).

These optimizations will never cause a parser which does not raise any exceptions to change behavior. If on the other hand a parser does raise exceptions, Spicy takes slightly more liberties and allows the final program to raise fewer exceptions. Explicit throw statements are always respected.

3.2. Toolchain

Is there a way to speed up compilation of Spicy code?

Please see Compilation Performance.

3.3. Zeek

See Zeek’s Spicy FAQ devel/spicy/faq.html.