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https://github.com/elliottt/easy-smt
Easy SMT solver interaction
https://github.com/elliottt/easy-smt
Last synced: 20 days ago
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Easy SMT solver interaction
- Host: GitHub
- URL: https://github.com/elliottt/easy-smt
- Owner: elliottt
- License: apache-2.0
- Created: 2022-12-29T00:02:01.000Z (almost 2 years ago)
- Default Branch: main
- Last Pushed: 2023-09-05T06:17:43.000Z (about 1 year ago)
- Last Synced: 2024-05-22T21:33:31.207Z (6 months ago)
- Language: Rust
- Size: 51.8 KB
- Stars: 21
- Watchers: 4
- Forks: 3
- Open Issues: 2
-
Metadata Files:
- Readme: README.md
- License: LICENSE-APACHE
Awesome Lists containing this project
- awesome-rust-formalized-reasoning - easy-smt - smt):star: - easy SMT solver interaction (Inspired by the [simple-smt haskell](https://hackage.haskell.org/package/simple-smt) package.). (Projects / Libraries)
README
easy-smt
An easy way to interact with an SMT solver!
## About
`easy-smt` is a crate for interacting with an SMT solver subprocess. This crate
provides APIs for
* building up expressions and assertions using [the SMT-LIB 2
language](https://smtlib.cs.uiowa.edu/),
* querying an SMT solver for solutions to those assertions,
* and inspecting the solver's results.
`easy-smt` works with any solver, as long as the solver has an interactive REPL
mode. You just tell `easy-smt` how to spawn the subprocess.
## Example
```rust
use easy_smt::{ContextBuilder, Response};
fn main() -> std::io::Result<()> {
// Create a new context, backed by a Z3 subprocess.
let mut ctx = ContextBuilder::new()
.solver("z3", ["-smt2", "-in"])
.build()?;
// Declare `x` and `y` variables that are bitvectors of width 32.
let bv32 = ctx.bit_vec_sort(ctx.numeral(32));
let x = ctx.declare_const("x", bv32)?;
let y = ctx.declare_const("y", bv32)?;
// Assert that `x * y = 18`.
ctx.assert(ctx.eq(
ctx.bvmul(x, y),
ctx.binary(32, 18),
))?;
// And assert that neither `x` nor `y` is 1.
ctx.assert(ctx.not(ctx.eq(x, ctx.binary(32, 1))))?;
ctx.assert(ctx.not(ctx.eq(y, ctx.binary(32, 1))))?;
// Check whether the assertions are satisfiable. They should be in this example.
assert_eq!(ctx.check()?, Response::Sat);
// Print the solution!
let solution = ctx.get_value(vec![x, y])?;
for (variable, value) in solution {
println!("{} = {}", ctx.display(variable), ctx.display(value));
}
// There are many solutions, but the one I get from Z3 is:
//
// x = #x10000012
// y = #x38000001
//
// Solvers are great at finding edge cases and surprising-to-humans results! In
// this case, I would have naively expected something like `x = 2, y = 9` or
// `x = 3, y = 6`, but the solver found a solution where the multiplication
// wraps around. Neat!
Ok(())
}
```
## Debugging
### Displaying S-Expressions
Want to display an S-Expression that you've built up to make sure it is what you
expect? You can use the `easy_smt::Context::display` method:
```rust
use easy_smt::ContextBuilder;
let ctx = ContextBuilder::new().build().unwrap();
let my_s_expr = ctx.list(vec![
ctx.atom("hi"),
ctx.atom("hello"),
ctx.numeral(42),
]);
let string = format!("{}", ctx.display(my_s_expr));
assert_eq!(string, "(hi hello 42)");
```
### Logging Solver Interactions
Need to debug exactly what is being sent to and received from the underlying
solver? `easy-smt` uses the `log` crate and logs all communication with the
solver at the `TRACE` log level.
For example, you can use `env_logger` to see the log messages. Initialize the
logger at the start of `main`:
```rust
fn main() {
env_logger::init();
// ...
}
```
And then run your program with the `RUST_LOG="easy_smt=trace"` environment
variable set to see the `TRACE` logs:
```shell
$ RUST_LOG="easy_smt=trace" cargo run --example sudoku
[2023-01-09T23:41:05Z TRACE easy_smt::solver] -> (set-option :print-success true)
[2023-01-09T23:41:05Z TRACE easy_smt::solver] <- success
[2023-01-09T23:41:05Z TRACE easy_smt::solver] -> (set-option :produce-models true)
[2023-01-09T23:41:05Z TRACE easy_smt::solver] <- success
[2023-01-09T23:41:05Z TRACE easy_smt::solver] -> (set-option :produce-unsat-cores true)
[2023-01-09T23:41:05Z TRACE easy_smt::solver] <- success
[2023-01-09T23:41:05Z TRACE easy_smt::solver] -> (declare-fun cell_0_0 () Int)
[2023-01-09T23:41:05Z TRACE easy_smt::solver] <- success
[2023-01-09T23:41:05Z TRACE easy_smt::solver] -> (assert (and (> cell_0_0 0) (<= cell_0_0 9)))
[2023-01-09T23:41:05Z TRACE easy_smt::solver] <- success
[2023-01-09T23:41:05Z TRACE easy_smt::solver] -> (declare-fun cell_0_1 () Int)
[2023-01-09T23:41:05Z TRACE easy_smt::solver] <- success
[2023-01-09T23:41:05Z TRACE easy_smt::solver] -> (assert (and (> cell_0_1 0) (<= cell_0_1 9)))
[2023-01-09T23:41:05Z TRACE easy_smt::solver] <- success
...
```
### Replaying Solver Interactions
You can save all commands that are being sent to the solver to a file that you
can replay without needing to dynamically rebuild your expressions, assertions,
and commands.
```rust
use easy_smt::ContextBuilder;
fn main() -> std::io::Result<()> {
let ctx = ContextBuilder::new()
// Everything needed to replay the solver session will be written
// to `replay.smt2`.
.replay_file(Some(std::fs::File::create("replay.smt2")?))
.solver("z3", ["-smt2", "-in"])
.build()?;
// ...
Ok(())
}
```
## Inspiration
Inspired by the [`simple-smt`](https://hackage.haskell.org/package/simple-smt)
haskell package.