Commit Graph

6 Commits

Author SHA1 Message Date
James Shubin
b8f8ec8aa3 lang: parser, funcs: Take out the built-in history function
It's a normally named function for now, until we think of a common
package to move it into.

Hopefully this makes improving the lexer and parser easier for now. We
can consider bringing it back if needed.
2023-10-09 17:19:08 -04:00
James Shubin
90fd8023dd lang, engine: Add a facility for resources to export constants
Since we focus on safety, it would be nice to reduce the chance of any
runtime errors if we made a typo for a resource parameter. With this
patch, each resource can export constants into the global namespace so
that typos would cause a compile error.

Of course in the future if we had a more advanced type system, then we
could support precise types for each individual resource param, but in
an attempt to keep things simple, we'll leave that for another day. It
would add complexity too if we ever wanted to store a parameter
externally.

Lastly, we might consider adding "special case" parsing so that directly
specified fields would parse intelligently. For example, we could allow:

	file "/tmp/hello" {
		state => exists,	# magic sugar!
	}

This isn't supported for now, but if it works after all the other parser
changes have been made, it might be something to consider.
2020-01-29 11:16:04 -05:00
James Shubin
9dae5ef83b engine: resources: Improve the file res and add strict state
This might be slightly controversial, in that you must specify the state
if a file would need to be created to perform the action. We no longer
implicitly assume that just specifying content is enough. As it turns
out, I believe this is safer and more correct. The code to implement
this turns out to be much more logical and simplified, and does this
removes an ambiguous corner case from the reversed resource code.

Some discussion in: https://github.com/purpleidea/mgmt/issues/540

This patch also does a bit of related cleanup.
2019-09-14 16:07:53 -04:00
James Shubin
046b21b907 lang: Refactor most functions to support modules
This is a giant refactor to move functions into a hierarchial module
layout. While this isn't entirely implemented yet, it should work
correctly once all the import bits have landed. What's broken at the
moment is the template function, which currently doesn't understand the
period separator.
2018-12-20 21:21:30 -05:00
James Shubin
837388ae4e lang: types, funcs: Add simple function API
This patch adds a simple function API for writing simple, pure
functions. This should reduce the amount of boilerplate required for
most functions, and make growing a stdlib significantly easier. If you
need to build more complex, event-generating functions, or statically
polymorphic functions, then you'll still need to use the normal API for
now.

This also makes all of these pure functions available automatically
within templates. It might make sense to group these functions into
packages to make their logical organization easier, but this is a good
enough start for now.

Lastly, this added some missing pieces to our types library. You can now
use `ValueOf` to convert from a `reflect.Value` to the corresponding
`Value` in our type system, if an equivalent exists.

Unfortunately, we're severely lacking in tests for these new types
library additions, but look forward to growing some in the future!
2018-02-21 21:32:31 -05:00
James Shubin
b19583e7d3 lang: Initial implementation of the mgmt language
This is an initial implementation of the mgmt language. It is a
declarative (immutable) functional, reactive, domain specific
programming language. It is intended to be a language that is:

* safe
* powerful
* easy to reason about

With these properties, we hope this language, and the mgmt engine will
allow you to model the real-time systems that you'd like to automate.

This also includes a number of other associated changes. Sorry for the
large size of this patch.
2018-01-20 08:09:29 -05:00