metaborg-ministratego
This repository contains an implementation of core subset of Stratego transformation language. The implementation is written using version 3 of the Spoofax language workbench. This project was written as part as a case-study for Dynamix: A Domain-Specific Language for Dynamic Semantics.
You can import this repository in your Spoofax 3 eclipse instance by following the steps here.
Supported Constructs
The following constructs are supported by this version of miniStratego:
Terms:
- Integers
- Strings
- Lists
Strategies:
- fail
- id
- Match (
?<pattern>) - Build (
!<pattern>) - Seq (
s1; s2) - Guarded choice (
s1 < s2 + s3) - some, one, all
- let bindings (
let <decl*> in s end)
These features should support complete enough to express all Stratego programs. You will likely need to desugar various things though. For example:
foo: a -> b
where c := d
will need to be desugared to
foo(|) = ?tmp0; !d; ?c; !tmp0; ?a; !b
miniStratego is fully compliant with core Stratego, except for one crucial difference: variables are deterministically bound. This means that variables bound in an invocation to a strategy will not persist on the next invocation to that strategy, nor can they escape "outside" of the strategy. To illustrate:
where(s|) = ?x; s; !x
// in Stratego, this works fine and prints "foo"
test(|) = !"foo"; where(?y|); !y; debug
// in miniStratego, this is an error
// the binding of `y` cannot escape the `y`
test(|) = !"foo"; where(?y|); !y; debug
// Undefined variable 'y' ^^
miniStratego ships with various "prim"s: strategies implemented directly in Tim source. Their implementations can be found in ministratego/src/dynamics/native.dx. See ministratego/test.mstr for an example on how to declare and access them.
Contents
This language project contains the following parts:
ministratego/src/syntax: The SDF3 grammar definition for miniStratego, based on the core Stratego syntax from the Stratego repository.chocopy/src/statics: A simple Statix specification for miniStratego, that additionally keeps track of whether a pattern will bind or match on a value.chocopy/src/dynamics: The Dynamix specification for miniStratego.
License
The files in this repository are licensed under the Apache License, Version 2.0. You may use the files in this repository in compliance with the license.