ascent 0.8.0

Logic programming in Rust
Documentation 
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//! Context Sensitive Flow Graph with Records
//!
//! The following example demonstrates one way of integrating context information into a control flow graph.
//!
//! The type program point (`ProgPoint`) aggregates an instruction and an (abstract) context (`Context`) into a new entity
//! which is utilized as the node type of the flow graph. Note that in this version flow is a simpler,
//! binary relation and typos mixing up instructions and contexts of different program points are effectively prevented.
//!
//! Also, as we will see below, the flow relation could now be modelled utilizing a generalized graph component,
//! thereby inheriting a library of derived relations.
//!
//! (Adapted from https://souffle-lang.github.io/examples#context-sensitive-flow-graph-with-records)

use ascent::ascent;

#[derive(Clone, Eq, PartialEq, Hash, Debug)]
pub struct Instr(&'static str);

#[derive(Clone, Eq, PartialEq, Hash, Debug)]
pub struct Context(&'static str);

#[derive(Clone, Eq, PartialEq, Hash, Debug)]
pub struct ProgPoint(Instr, Context);

#[derive(Clone, Eq, PartialEq, Hash, Debug)]
pub enum Res {
   Ok,
   Err,
}

ascent! {
    // Facts:

    relation succ(ProgPoint, ProgPoint);

    // Rules:

    relation flow(ProgPoint, ProgPoint);

    flow(p1, p2) <-- succ(p1, p2);
    flow(p1, p3) <-- flow(p1, p2), flow(p2, p3);

    relation res(Res);

    res(Res::Ok) <-- flow(ProgPoint(Instr("w1"), Context("c1")), ProgPoint(Instr("r2"), Context("c1")));
    res(Res::Err) <-- flow(ProgPoint(Instr("w1"), Context("c1")), ProgPoint(Instr("r2"), Context("c2")));
}

fn main() {
   let mut prog = AscentProgram::default();

   prog.succ = vec![
      (ProgPoint(Instr("w1"), Context("c1")), ProgPoint(Instr("w2"), Context("c1"))),
      (ProgPoint(Instr("w2"), Context("c1")), ProgPoint(Instr("r1"), Context("c1"))),
      (ProgPoint(Instr("r1"), Context("c1")), ProgPoint(Instr("r2"), Context("c1"))),
      (ProgPoint(Instr("w1"), Context("c2")), ProgPoint(Instr("w2"), Context("c2"))),
      (ProgPoint(Instr("w2"), Context("c2")), ProgPoint(Instr("r1"), Context("c2"))),
      (ProgPoint(Instr("r1"), Context("c2")), ProgPoint(Instr("r2"), Context("c2"))),
   ];

   prog.run();

   let AscentProgram { res, .. } = prog;

   assert_eq!(res, vec![(Res::Ok,),]);
}